Mastering days of inventory on hand: A Guide to Profit for Woodworking Shops

Think about every piece of lumber, every sheet of plywood, and every box of hardware sitting on your shelves. Now, picture all of it as stacks of cash you can't touch. That's what inventory really is. And the most critical metric for getting a handle on this hidden cost is your days of inventory on hand. It tells you exactly how long it takes to turn those materials into money in the bank.

Why Your Inventory Is Your Biggest Hidden Cost

In a custom woodworking or millwork shop, raw materials aren't just supplies—they're one of your biggest investments, right up there with labor and machinery. Every single day that inventory sits idle, it's silently eating into your profits. This isn't just about the initial purchase price; it's about the cash flow that's frozen, trapped on a shelf instead of being used for payroll, new equipment, or growing your business.

For a shop that deals with fluctuating material costs and complex, one-of-a-kind projects, understanding your days of inventory on hand (DOH) is an absolute must. Think of it as a financial health check for your entire operation. It reveals precisely how many days your current stock will last based on how fast you're actually using it.

The Double-Edged Sword of Inventory Levels

Having a high DOH isn't just a sign of inefficiency; it’s a direct hit to your bottom line. It means your capital is gathering dust instead of working for you. But the opposite is just as dangerous. A DOH that’s too low can bring your shop to a screeching halt, leading to crippling production delays and angry clients when you run out of essential materials mid-job.

Striking the right balance is the key to:

• Improving Cash Flow: Unlocking the capital that was previously tied up in slow-moving stock.
• Increasing Efficiency: Making sure you have exactly what you need for upcoming projects without paying to store a mountain of excess.
• Boosting Profitability: Cutting down on waste from damaged or obsolete materials and avoiding those costly rush-order fees.

The concept is simple but incredibly powerful: inventory is working capital. The faster you convert materials into a finished product and then into cash, the healthier and more agile your business becomes.

This metric became a game-changer for businesses as global online sales shot past $7 trillion. While e-commerce giants might aim for a 30-60 day window, for a custom woodworking shop, anything higher can mean huge amounts of cash are tied up in raw timber or finished cabinets. DOH reveals the pulse of your cash flow—how many days inventory lingers before it's sold.

Mastering this one number gives you a surprising amount of control. It helps turn inventory from a necessary evil into a real strategic asset. By actively tracking and optimizing your days of inventory on hand, you can start making smarter purchasing decisions, fine-tune your production schedule, and ultimately protect your profits. The first step is properly understanding how to assign value to your stock, which you can learn more about by exploring different methods of valuing inventory.

How to Calculate Your Days of Inventory on Hand

Alright, now that we’ve established how much idle inventory can drain your cash flow, let's roll up our sleeves and get into the math. Don't worry, this isn't some complex accounting wizardry. Calculating your Days of Inventory on Hand (DOH) is a straightforward tool every shop owner should have in their back pocket to gauge the health and speed of their operation.

At its heart, the formula is simple.

The Days of Inventory on Hand Formula: (Average Inventory / Cost of Goods Sold) x Number of Days in Period

Think of this number as the fuel gauge for your business. It tells you exactly how many days you could operate, building and shipping products, before your current inventory completely runs out. It’s a powerful snapshot of your efficiency.

But before we can plug in numbers, we need to be crystal clear on what those terms actually mean for a real-world woodworking shop.

Defining The Core Components

Getting this right is all about using the correct inputs. Let's break down the two key pieces of the formula.

• Average Inventory: This isn't just a snapshot of what you have on the rack today. It’s a more honest look calculated over a specific period—like a month, quarter, or year. You find it by adding your Beginning Inventory value to your Ending Inventory value and then dividing that by two. This simple step smooths out the bumps from big material orders or when a massive project finally ships out the door.

• Cost of Goods Sold (COGS): For any custom millwork or cabinet shop, COGS is the sum of all direct costs that went into the products you actually sold during that period. We're talking more than just the price of lumber. This includes all your raw materials, hardware, fasteners, finishes, and the direct labor of the craftspeople who brought those designs to life. For a deeper dive, check out our guide on how to calculate your cost of goods manufactured.

This isn't just a metric for small shops, either. Retail giants use the same logic to manage their sprawling operations. The key takeaway is that DOH gives you a clear, honest number to track your shop's performance.

Putting The DOH Formula Into Practice

Let's walk through a tangible example to see how this works. We'll use the financials of a hypothetical custom cabinet shop over one quarter (90 days).

Below is a step-by-step breakdown that takes you from raw numbers to your final DOH figure.

Based on this calculation, our custom cabinet shop has 39.6 days of inventory on hand. This means it holds enough material and finished goods to sustain its current rate of sales for nearly 40 days without purchasing anything new. That's a powerful piece of information.

Knowing your DOH—also commonly referred to as Inventory turnover days—is the first step. You can calculate it for your raw materials and finished goods separately to get an even clearer picture.

For instance, if your raw materials DOH is 45 days, you know you have a month-and-a-half supply of lumber sitting there. If your finished goods DOH is 30 days, it means the average cabinet sits in your warehouse for a month before shipping.

Each number tells a story about where your cash is tied up and where you can find opportunities to improve. By running this calculation regularly, you stop guessing and start making data-driven decisions that directly impact your bottom line.

What a Good DOH Number Actually Looks Like

So you've calculated your shop's DOH. The first impulse is often to Google "what's a good days on hand number?" But here’s the honest truth from someone who’s been in the trenches: there's no magic number.

A healthy DOH for a high-volume shop cranking out standard cabinet boxes would be a five-alarm fire for a custom furniture maker working with rare, imported hardwoods. The "right" number is all about your specific business. It depends entirely on your model, your materials, and the promises you make to your clients. Think of it less like a fixed target and more like the oil pressure gauge on your truck—you need to know how to read it in the context of what you’re hauling and where you’re going.

For example, a shop that builds custom cabinetry from readily available maple might aim for a lean 30-45 days of inventory. Their supply chain is solid and predictable, so they can run lean without much risk. But what about a luthier who sources exotic koa from Hawaii with a six-month lead time? Their raw material DOH will be sky-high by comparison, and that’s not just okay—it’s essential for their business to even function.

The Dangers of Flying Too High or Too Low

Getting this number wrong in either direction can be a silent killer for a woodworking business. Understanding the risks on both ends is the first step to finding that sweet spot for your own operation.

A consistently high DOH, which for many shops starts to get uncomfortable over 90 days, is like a financial anchor. It drags you down in a few critical ways:

• Wasted Capital: Every board foot of walnut sitting on the rack is cash that could be used for a new CNC, a marketing campaign, or just making payroll.
• Storage Costs: More stuff needs more space. That means higher rent, bigger insurance bills, and the cost of keeping that space climate-controlled so your material doesn't warp or check.
• Risk of Obsolescence: That beautiful stack of ash can get damaged, discolored, or fall out of fashion. Suddenly, a valuable asset becomes a sunk cost you have to liquidate at a loss.

On the flip side, running too lean can be just as dangerous. An aggressively low DOH creates a fragile business that can shatter with the slightest disruption. The risks are just as real:

• Production Shutdowns: Your supplier has a surprise delay, and just like that, your entire shop floor grinds to a halt. Now you're paying your team to stand around.
• Missed Deadlines: Nothing craters a reputation faster than telling a client their project is delayed because you ran out of drawer slides. Cue the frantic phone calls, rush shipping fees, and angry customers.
• Lost Sales: A potential client walks in, ready to sign a contract, but you can't start for weeks because you don't have the materials. They'll just go down the street to someone who can.

The goal isn't to hit zero. It's to find the perfect balance that keeps your cash flowing freely without ever putting your production schedule and client commitments at risk.

Benchmarking Against the Broader Industry

While your own shop’s trends are what matter most, it helps to peek over the fence and see what’s happening in the wider manufacturing world. It gives you some much-needed context.

For instance, recent industry reports show that average lead times for production materials can stretch to 79 days. Many manufacturers are planning their inventory around 90-day cycles just to stay safe. Knowing this helps you see if your own numbers are in the right ballpark or if you’re an outlier. You can see more on these manufacturing trends at ismworld.org to get a better feel for the landscape.

Ultimately, your days of inventory on hand tells a story. When you learn to read that story—in the context of your lead times, your cash flow, and your goals—you stop just tracking a number. You start making smart, strategic decisions that put real, sustainable profit in your pocket.

How to Actually Lower Your Days of Inventory on Hand

Knowing your days of inventory on hand is one thing. Actually reducing it is where the magic happens and you start to see serious financial gains. Moving from just having the numbers to taking action requires a fundamental shift in how you run everything from purchasing to production.

This isn’t about guesswork or gut feelings. It's about pulling specific, tangible levers in your operations to make your business leaner, faster, and much more profitable. The real goal is to shrink that window between paying for materials and getting paid for a finished product. For woodworkers and millwork shops, this means adopting smarter strategies built for the real world of custom manufacturing.

Let Data Drive Your Purchasing, Not Fear

One of the biggest culprits behind a high DOH is buying based on the fear of running out. It’s an understandable impulse, but this "just-in-case" approach is a surefire way to end up with a mountain of slow-moving stock tying up your cash. The solution is to replace that fear with hard data.

Start by digging into your past sales and production history to find real, actionable patterns.

• Which materials show up again and again in your most popular projects?
• Do you see seasonal spikes you can plan for, like a rush on outdoor projects in the spring?
• What materials are essential for your bread-and-butter jobs?

When you can answer these questions, you stop ordering based on a hunch and start building a reliable forecast. This lets you order what you know you’ll need, not what you think you might need, which is a game-changer for cutting down raw material holding time.

Bring Just-In-Time Thinking to Your A-List Materials

The "Just-in-Time" (JIT) philosophy isn't just for massive auto plants. At its core, the principle is incredibly simple: hold as little inventory as you can get away with and have materials show up right as you need them.

While you probably can't do this for that rare slab of walnut with a 12-week lead time, you can absolutely apply it to your high-velocity items. Identify your "A-items"—the common materials like standard MDF, drawer slides, and fasteners that you burn through every single week.

By working with your suppliers to arrange smaller, more frequent deliveries, you can keep your shop running smoothly without sinking thousands of dollars into excess plywood or hardware. Your supplier’s warehouse effectively becomes an extension of your own.

This strategy requires solid communication and trust with your vendors, but the impact on your cash flow is immediate and significant. For more on this, check out our guide to effective stock and replenishment strategies.

Optimize Your Shop Floor to Speed Up Cash Flow

Your DOH isn't just about what's sitting on the racks; it’s also about how fast you can turn those raw materials into a finished, invoiced product. Every inefficiency on the shop floor inflates your work-in-process and finished goods inventory, keeping your cash trapped for longer than necessary.

Start hunting for the bottlenecks in your production cycle. Is one machine holding up three other jobs? Are people waiting around for materials or clear instructions? Streamlining your workflow is a massive lever for lowering your DOH.

Consider these high-impact optimizations:

• Smarter CNC Nesting: Use software to squeeze every last bit of usable material out of each sheet. This not only reduces your raw material consumption but also directly improves your Cost of Goods Sold.
• Real-Time Project Tracking: Put a system in place where anyone can see the exact status of a job at a glance. This clears up confusion, cuts down the dead time between process steps, and gets projects out the door faster.
• Standardize Common Tasks: Create simple, repeatable processes for the things you do every day. Consistency is the key to speed and reducing errors that lead to costly rework.

Each tiny improvement you make to your production velocity shaves time off your inventory cycle.

This shift from a traditional, "just-in-case" mindset to a modern, data-driven approach can feel like a big leap, but the differences are stark.

Comparing Inventory Management Strategies

Ultimately, a modern approach turns inventory management from a necessary evil into a strategic advantage.

When you combine intelligent forecasting with strategic purchasing and an efficient shop floor, you build a powerful system that consistently drives your DOH down. The result? More cash in your business where it belongs.

Let Technology Do the Heavy Lifting to Lower Your Inventory Days

Knowing which levers to pull is one thing. Actually pulling them consistently in a chaotic shop is another beast altogether. Let's be honest—manually tracking every board foot, every job status, and every cut sheet is a recipe for disaster. It's not just difficult; it's nearly impossible and leaves you wide open to expensive mistakes.

This is where the right technology stops being a "nice-to-have" and becomes your secret weapon. It can transform inventory management from a reactive headache into a proactive, profit-driving part of your business. A modern, integrated platform connects your sales team, your shop floor, and your purchasing into one seamless flow. It gets rid of the guesswork that bloats your inventory and ties up your cash.

Stop Over-Ordering with a Live Inventory Sync

What’s a classic reason for high inventory days? A massive disconnect between what you think you have, what you actually have, and what you’ve already sold. Without a live, accurate count, most shops fall into the trap of over-buying materials "just in case." That safety net gets real expensive, real fast.

When your e-commerce site, quoting tools, and shop floor all pull from the same live inventory data, your counts are always right. As a job moves through production and chews up materials, the system automatically deducts them. This means you only order what you truly need for the work ahead, preventing that slow, costly pile-up of raw materials.

A single source of truth for your inventory closes the information gap that leads to over-ordering. You can finally stop buying based on fear and start purchasing based on actual, real-time demand.

Take a look at this TimberCloud dashboard. You can see live inventory levels at a glance—what's on hand and what's available.

This isn't just data; it's clarity. It’s the kind of visibility that lets you make smarter, faster purchasing decisions.

Crush Bottlenecks with Real Production Tracking

Your inventory problem isn't just about the raw materials sitting on the rack. Your finished goods and work-in-process (WIP) play a huge part, too. Projects that get stuck somewhere in the production pipeline just sit there, trapping your capital and pushing out your cash flow. If you can't see where the logjams are, how can you possibly fix them?

Production tracking tools give you a crystal-clear map of every job as it moves through your shop. You can see exactly where a project is, how long it’s been stuck there, and what’s supposed to happen next. This unlocks the ability to:

• Spot the Holdups: Instantly see which machine or process is slowing everything down.
• Move Your People: Shift team members to the bottleneck to get jobs flowing smoothly again.
• Crank Up Throughput: Speed up the entire production cycle, turning raw materials into cash in the bank much faster.

When you increase your production velocity, you directly slash the time your money is tied up in half-finished work. This is one of the most effective ways to drive down your days of inventory on hand for finished goods.

Squeeze More out of Every Sheet with Automation

Waste is the silent killer of profit. It's also a direct hit to your Cost of Goods Sold, which throws your inventory day calculation way off. Manually planning cuts on a sheet of plywood or nesting parts for the CNC almost always leaves usable material on the floor. That scrap represents a sunk cost that inflates your inventory expenses.

Tools like automated cut sheets and nesting software take the human error and guesswork out of the equation. They analyze all the parts for a job and calculate the absolute most efficient layout to minimize waste. You simply get more finished parts from every single sheet you buy.

By boosting your yield, you cut your raw material consumption and lower your COGS. The result? A much healthier inventory number and better margins on every single project. It’s a straight line from smarter cutting to a stronger bottom line.

Building Your Inventory Reporting Workflow

Getting a handle on your days of inventory on hand isn't something you do once and forget about. It's a discipline. To see real, lasting change, you need a simple but powerful workflow that turns this number from a line on a spreadsheet into a tool that drives action. This creates a rhythm of review and adjustment, weaving efficiency right into your shop's DNA.

A great reporting system isn't about complexity. It’s about consistency, clear ownership, and a direct line to your business goals. The whole point is to shift from putting out inventory fires to proactively steering your cash flow.

Establishing Your Reporting Cadence

First things first, you need a schedule. Decide how often you'll review your inventory numbers. Different meetings serve different purposes, making sure everyone from the shop floor to the front office is on the same page.

• Monthly Operational Review: Think of this as your tactical huddle. The shop manager or operations lead should run this, calculating DOH for both raw materials and finished goods. The mission here is to catch short-term blips before they become big problems—like a sudden spike in how long you're holding a specific type of lumber or a bottleneck causing finished cabinets to stack up.
• Quarterly Strategic Review: This one’s for the leadership team. You’ll zoom out and look at the DOH trend over the last three months, putting it in the context of the company's overall health. This is where you connect the dots between inventory performance and your financial statements, setting bigger goals for the future.

Setting Actionable Goals and KPIs

Once you know your numbers, you can set targets that actually mean something. A goal like "lower our DOH" is just wishful thinking. Get specific. Aim for something like, "reduce raw material DOH by 10% over the next six months" by tightening up supplier lead times and getting better at forecasting.

Your DOH metric shouldn't be an island. It tells a much richer story when you look at it alongside other key performance indicators (KPIs).

Make sure you're tracking your inventory turnover rate right next to your DOH. They're two sides of the same coin. A higher turnover always means a lower DOH, and seeing them together drives home how much inventory speed impacts your bottom line.

This is where technology can become the backbone of your entire workflow, taking the manual grunt work out of collecting data for these critical metrics.

As you can see, features like real-time sync and production tracking feed directly into a smarter, data-driven approach to inventory. To get the most out of these systems, leaning on advanced tools for AI data analysis can reveal hidden patterns in your inventory, paving the way for better, more proactive decisions.

By building this simple reporting structure, you turn DOH from a passive number into an active management tool. It creates accountability and makes sure the insights you pull from your data lead to real-world actions that boost your efficiency and profitability.

Frequently Asked Questions

When you start digging into days of inventory on hand, a few common questions always seem to pop up. Let's tackle some of the ones we hear most often from custom woodworking shops so you can start using this metric with confidence.

How Often Should I Calculate DOH?

For keeping a tight grip on your day-to-day operations, running your DOH numbers monthly is a great rhythm to get into. This gives you a chance to spot and fix a problem—like a pile of walnut veneer that isn't moving—before it gets out of hand.

When you zoom out for strategic planning or financial reporting, a quarterly calculation usually does the trick. The real secret isn't the frequency, though; it's consistency. A single number doesn't tell you much, but tracking the trend over time is where the magic happens.

What’s The Difference Between DOH And Inventory Turnover?

Think of them as two sides of the same coin. Both metrics are measuring how efficiently you're managing your inventory, just from a slightly different perspective.

• Days of Inventory on Hand tells you how many days your current stock will last. It's a measure of time.
• Inventory Turnover tells you how many times you sell and replace your entire inventory over a set period, usually a year. It's a measure of frequency.

A high turnover rate goes hand-in-hand with a low DOH. Both are signs of a healthy, lean operation. But for day-to-day cash flow management, many shop owners find DOH more intuitive because it’s framed in days, not abstract "turns."

A DOH of 30 days is the same as an inventory turnover of roughly 12 times per year. Both tell a story of inventory that’s moving quickly and not gathering dust.

Can My DOH Be Too Low?

Yes, absolutely. While a low DOH is usually something to celebrate, a number that's too low can be a serious warning sign. It often means you're flirting with stockouts.

In a custom millwork shop, that could mean running out of a specific lumber species or a critical piece of hardware right in the middle of a high-stakes project. The resulting production delays can lead to blown deadlines and, even worse, a loss of customer trust. The goal isn't to get to zero; it's to find that sweet spot where you have just enough material to keep jobs flowing smoothly without tying up a fortune in capital.

---

Ready to stop guessing and start making data-driven decisions? See how TimberCloud gives you the real-time visibility and shop-floor control you need to optimize your inventory, reduce your DOH, and boost your bottom line.

Explore TimberCloud’s All-In-One Platform