Spreadsheets vs. Inventory Software for Woodworkers: The Rack Is Not One Row

The National Hardwood Lumber Association grading rules make a promise about your lumber, and it is a smaller promise than most people read it as. Per the American Hardwood Export Council's published summary of those rules, a board graded FAS is certified to yield 83-1/3% to 100% clear-wood cuttings. No. 1 Common yields from 66-2/3% up to, but not including, the FAS minimum. No. 2A Common starts at 50%. Those are certified clear-cutting minimums for the grade — a different measure from the total rough-to-finished yield you get after kerf and planing, which is lower again. Either way, they are not estimates of what a clumsy woodworker wastes. They are the definition of the grade.

The same rulebook measures hardwood in the rough, and surfacing takes 3/16 of an inch off nominal thickness on stock 1-1/2 inches and under — so the 4/4 you paid for arrives at your bench as 13/16.

The short answer: a spreadsheet is the right tool right up until it stops answering questions faster than walking to the rack and counting. Three things push a woodshop past that line, and the rest of this post works through each one — the same species sitting on your rack in several thicknesses and grades at different prices, a rough-to-finished conversion you have quietly stopped trusting, and commissions in progress with material already consumed. Any one of them is a nuisance you can absorb. Two of them means the sheet is costing you more than it saves.

That gap raises a question worth actually asking rather than assuming the answer to: if the industry that sells you lumber documents, in writing, that a third of a No. 1 Common board may not be usable clear stock and that an eighth of the thickness is coming off before you start — where does your spreadsheet record that? For most woodshops the honest answer is that it does not record it anywhere. There is one row per species, one price per board foot, and a quiet assumption that the number on the invoice is a number about your shop.

It is not. It is a number about the truck.

Problem 1: your rack is one row called "walnut"

Open the materials tab. There is almost certainly a row that says Walnut with a price next to it, and that price is doing an enormous amount of unearned work.

Here is what a working shop's walnut actually looks like after eighteen months of buying it:

Four materials. One row. And whatever single number sits in that row — the most recent price, the first one you ever entered, an average someone computed once — it describes none of the four. Quote a cutting board off the blended figure and you have priced it with lumber that does not exist.

This is not a discipline problem, and it is worth being precise about that, because the usual framing here is that people who still use spreadsheets are disorganized. Organization is not the differentiator. The problem is that the sheet's structure invites one row per species, because that is how you talk about lumber.

You say "I need walnut." You do not say "I need 4/4 kiln-dried No. 1 Common walnut from the sawyer at the May price." The row matches the sentence, not the rack.

The fix is structural, not clerical. Species, thickness, and grade are three attributes of one material, and each combination is its own item with its own cost. Split the row and the blended-average problem disappears on its own, because there is no longer anything to blend. The reason this is worth doing in software rather than by adding more rows to the sheet is what happens next — every one of those four lots also has a quantity, and quantities move every time you build something. Four rows you maintain by hand becomes forty rows in a shop that works in five species, and forty rows maintained by hand is where the sheet quietly stops being current.

Problem 2: the sheet stores a price, the shop performs a conversion

This is the expensive one, and the grading rules already explain why.

You buy in rough board feet. You build in finished dimensions. Between those two states, material leaves in four ways, and only one of them is your fault:

1. Thickness. Documented: 3/16 off nominal on 4/4 stock. That is 18.75% of the thickness, gone to the planer, before any decision you make.
2. Grade yield. Documented: No. 1 Common is certified to contain 66-2/3% clear cuttings at minimum. The defect is not a surprise. It is what you agreed to buy.
3. Kerf and trim. Shop-specific. Every rip takes a blade width; every crosscut takes the checked end.
4. The board that cracked. Occasional, unpredictable, real.

Say you need 3 board feet of finished, defect-free walnut for a cutting board, and you are working from 4/4 No. 1 Common at $9.40/bf.

Your spreadsheet does this:

3 bf × $9.40 = $28.20 of lumber in this board.

Your shop does this: to net 3 finished board feet out of that grade and thickness, you pull roughly 4.6 bf off the rack. Call it $43.24. (That 4.6 is illustrative — it is the compounded effect of the two documented losses above plus this hypothetical shop's kerf and trim. Yours will differ, and the only way to know it is to weigh or measure your own offcut bin against a few real builds. Do not borrow the number.)

The gap is $15.04 per board — a 53% understatement. At a hypothetical sixty boards a year — substitute your own volume — that is roughly $900 of material cost that never reaches a price tag. Not stolen, not wasted, not anybody's mistake. Just never written down.

The tell: the difference between a sheet that works and a sheet that lies is not formulas. It is whether anything in the workbook ever subtracts what you consumed from what you bought. Purchases live on one tab. Projects live on another. Nothing joins them, because joining them is a relationship rather than a formula.

The fix is to make a build consume material. When a project draws 4.6 bf of a specific lot out of stock, the rack goes down by 4.6 and the piece carries $43.24, and the two numbers stay married without you remembering to marry them. The per-project version of that math — how to measure your own yield ratio and set a price off it — is worked in full in Woodshop Math, and there is no point repeating it here.

Problem 3: five commissions in flight, and nowhere to put them

Candle makers and soap makers have a tidy inventory question because their products repeat. A woodshop's does not. On any given Tuesday you might be holding:

• A walnut bench, glued up, three weeks from delivery. Deposit taken and mostly spent. About $210 of lumber already consumed.
• Two end-grain cutting boards in finish, curing, unsellable for another 48 hours.
• A dining table where the lumber is bought and stickered but not yet milled.
• A repeat order of six coasters, done, boxed, waiting on the customer to confirm an address.
• A speculative piece for the fall show that you started in March and will finish in September, probably.

Now answer the question your accountant asks in January: what are you holding?

The spreadsheet's answer is whatever is left on the materials tab, which is wrong in both directions at once. It is too high, because the bench's $210 of walnut left the rack weeks ago and nobody decremented it. And it is too low, because that $210 has not vanished — it is standing in the corner under a moving blanket, and it is worth more now than it was as a plank.

There is no column for "milled, glued, and not yet a thing." Flat lists have two states: you have it or you do not. A commission shop lives almost entirely in the state between them.

The fix is a production run that stays open — material consumed and held against a specific build, so the value moves from the rack into the piece instead of falling off the edge of the workbook. It is the difference between an inventory list and an inventory system, and it is the single hardest thing to fake with tabs.

So which one should you actually use?

Here is the honest comparison, including the case for staying put.

The spreadsheet

Pros:

• Free, instant, and already built. There is no migration and no learning curve.
• Infinitely flexible. Your workbook fits your shop exactly because you shaped it that way, and no software will ever be that bespoke.
• Genuinely fast for a small, stable material list — nothing beats typing a number into a cell you already know the address of.
• Works offline, in a cold shop, on a laptop with sawdust in the keyboard.

Cons:

• Structure is voluntary. A workbook built correctly on Sunday can be three sources of truth by December, and there is no error message when it happens.
• No relationships. Purchases and projects can both be correct and still never speak to each other.
• No concept of work in progress, which is where a commission shop's money mostly lives.
• Maintenance scales with your material list, and material lists only ever grow.

Best for: one or two species, a handful of purchases a year, one build finished before the next begins, and a maker who genuinely enjoys keeping the sheet current.

Purpose-built inventory software

Pros:

• Structure is enforced rather than requested. Species-thickness-grade combinations stay distinct because the system will not let them collapse.
• Builds consume stock, so the rack and the cost sheet update from the same event.
• Work in progress has somewhere to live, and so does the value inside it.
• Cost history follows the lot, so a March quote and a July quote are built from the prices you actually paid.

Cons:

• A real setup evening, and a period of running two systems while you trust the new one.
• Opinionated. It will ask you to model your shop its way in places where the sheet let you improvise.
• Another login, another thing to keep current — the failure mode is a system that is structurally correct and six weeks stale.
• Overkill for a shop whose entire material holding fits on one wall and in one head.

Best for: several species across multiple thicknesses and grades, multiple commissions open at once, and a shop where somebody eventually needs to know what was consumed without going and looking.

The honest hybrid

Pros: keep the sheet for the things it is genuinely best at — a quick quote sketch, a cut list, a shopping list scribbled at the lumberyard — and put the material and build records where structure matters.

Cons: two places to look, and a discipline question about which one is authoritative. Answer that question once, out loud, or you will end up with the worst of both.

Best for: most shops in the middle, and most shops in the first year after switching.

What moving actually involves

Less than rebuilding the workbook a third time, which is the real alternative most people are choosing between.

Your species, thicknesses, grades, quantities, and the prices you paid export to CSV, which is exactly what inventory software imports. In Ardent Seller, the three problems above have three specific answers:

• Structured SKUs answer Problem 1. Species, thickness, and grade become attributes of one material rather than four unrelated rows that happen to start with the same word — so the rack stops collapsing into a row called "walnut."
• Cost lots answer Problem 2. Each purchase keeps the price you actually paid instead of dissolving into a blended average, so a build consumes the lumber it actually consumed at the price it actually cost.
• Production runs answer Problem 3. Material a build used is drawn from stock and held against that build, which is where the bench's $210 goes instead of falling off the edge of the workbook.

Test it the way you would test a new finish: on one piece, in parallel, before you commit the commission. Rebuild a single project end to end — buy the lumber, mill it, consume it, price it — and see whether the number that comes out the far end matches what the job actually cost you. That takes an evening on the free tier (plan details). For the same argument made without the woodworking specifics, the product-level comparison lives at spreadsheets vs. Ardent Seller.

And if the answer comes back "the sheet was fine," take that seriously. It is a legitimate result, and this is one of the few pieces of business advice where the do-nothing option is frequently correct.

You already know not to trust a board's nominal dimension. You mill a test piece, you set the calipers on it, you find out what it is rather than what the sticker said. The number in your materials tab deserves the same suspicion. It was written by somebody who has never been in your shop.

Start free, rebuild one commission, and check the number against the calipers.

Related reading

• Woodshop Math: Board Feet, Offcuts, and Pricing Custom Builds — The full board-foot method: measuring your own cutting yield, costing consumables, and building a project cost sheet you can quote from.
• A Day in a One-Person Woodshop — Where the hours go, hour by hour, including the clamp time and cure time nobody puts on an invoice.
• Spreadsheet Breakup — The signs any maker business, in any craft, has outgrown Excel — what switching genuinely costs and how to choose what replaces it.

Free resources

Free companion downloads if you want to put any of this into practice:

• Spreadsheet vs Inventory Software: The Decision Guide — A self-assessment scorecard and migration checklist, so the stay-or-switch call above gets made on evidence rather than on whichever tab annoyed you most this week.
• Monthly Inventory Count Sheet — A printable sheet with expected, actual, and variance columns. Walking the rack with it is how you find your own version of the 3-versus-4.6 board-foot number instead of borrowing this post's.
• Inventory Tracker Starter Kit — If the honest answer is that the sheet is still the right tool, use a better sheet: this one is already split by material rather than by product name.

This article is provided for educational purposes only and does not constitute financial, tax, or business advice. Lumber prices, yield ratios, and the per-board figures above are illustrative and will vary by species, grade, supplier, and your own milling practice. NHLA grade definitions are cited as published by the American Hardwood Export Council and may be superseded by the current edition of the NHLA rulebook. Consult a qualified accountant or small-business advisor before making financial decisions based on this content.