The short answer: a 20 percent markup is not a 20 percent margin. Markup is measured against your cost; margin is measured against the price you charge. Because price is always the bigger number, the margin percentage is always smaller than the markup percentage. Plan a year on the wrong one and the shortfall is real money that never existed.
A contractor sits down with his accountant in April. He knows his numbers, or thinks he does: he marks up every job 20 percent and he billed $410,000 last year, so there should be about $82,000 of gross profit in the pile. The accountant slides the statement across the desk. Gross profit: $68,000. Fourteen thousand dollars is just… not there.
Nothing was stolen. Nothing was wasted. The fourteen grand never existed, because a 20 percent markup was never a 20 percent margin, and he had been planning his year (his overhead, his own pay, his winter) on the wrong one.
This is probably the most expensive vocabulary mistake in the trades. It is pure arithmetic, it takes five minutes to understand permanently, and it is worth real money on every job you price from now on. Here is the whole thing.
Two words, two directions
Markup and margin describe the same gap (the difference between what a job costs you and what you charge), but they measure it from opposite ends.
Markup looks up from cost. It asks: how much did I add on top of what I spent?
Markup % = (price − cost) ÷ cost
Margin looks down from price. It asks: of the money the client paid me, how much did I keep?
Margin % = (price − cost) ÷ price
Same dollar gap, different denominator. And because price is always bigger than cost, the margin percentage is always smaller than the markup percentage on the same job. Always. That one-way relationship is the whole trap.
The markup and margin converter turns one into the other, in both directions, so you can check a number before you quote it.
The worked example, slowly
Say a job costs you $10,000 in materials, labor, and subs, and you apply your standard 20 percent markup.
- Cost: $10,000
- Markup: 20% of $10,000 = $2,000
- Price: $12,000
Now compute the margin on that same job:
- Gross profit: $12,000 − $10,000 = $2,000
- Margin: $2,000 ÷ $12,000 = 16.7%
Your "20 percent" job is a 16.7 percent job. On one job, that reads like pedantry. Across a year it is the accountant's missing $14,000: the contractor billing $410,000 at a true 16.7 percent margin keeps about $68,000 gross, not the $82,000 he budgeted around. He set his overhead, his draws, and his idea of a good year against a number that was never real.
The gap widens as the numbers grow. A few common markups, translated:
- 10% markup → 9.1% margin
- 15% markup → 13.0% margin
- 20% markup → 16.7% margin
- 25% markup → 20.0% margin
- 33.3% markup → 25.0% margin
- 50% markup → 33.3% margin
- 100% markup → 50.0% margin
Read that middle line again, because it is the fix for the most common case: if what you actually need is a 20 percent margin, you must apply a 25 percent markup. The contractor who needs 20 and applies 20 shorts himself 3.3 points of margin on every single job: invisibly, forever.
Where does the confusion cost you money?
The error is not academic. It shows up in specific, recurring places.
Setting prices against a margin target. Your overhead recovery and profit goals are naturally margin-shaped: "I need to keep 35 cents of every dollar billed." If you then implement that goal as a 35 percent markup, you are actually keeping 26 cents. The business plan and the pricing rule disagree, and the pricing rule wins.
Talking to your accountant or your banker. Financial statements speak margin, always: gross margin, net margin, as a share of revenue. If you speak markup in that room without translating, every number you say is inflated, and decisions get made on it. This conversation happens most dangerously at loan time.
Comparing yourself to benchmarks. When you hear that healthy residential remodelers run, say, a particular gross margin, that is a margin figure. Checking your markup against someone's margin benchmark tells you that you are doing better than you are.
Quoting from a sub's number. You get a plumbing sub's quote at $8,000 and add "your 15 percent" before it goes into the bid. If your business needs a 15 percent margin on subbed work, you just underpriced it: the $9,200 line carries only a 13 percent margin. Multiply across every sub on a large project and the general contracting fee you thought you built in has quietly shrunk by a tenth or more, on the portion of the job where your fee is the entire compensation for carrying the risk.
Discounting. This is the quiet killer. On the $12,000 job above, a client asks for "just 10 percent off." That $1,200 does not come off your costs. Those are fixed. It comes entirely out of your $2,000 gross profit. A 10 percent discount on the price destroyed 60 percent of the profit. Margin thinking makes that visible before you agree to it; markup thinking hides it until April.
Which one should you use, and when?
Neither word is wrong. Each has a home, and the skill is not mixing them.
Use markup when building a price. Markup is a construction tool: start from cost, multiply up, arrive at price. It is how you price materials on an invoice, how you add your fee to a sub's quote, how cost-plus contracts are written. It works from the numbers you actually have in hand at estimating time.
Use margin when judging a result. Margin is a measurement tool: it tells you what share of revenue survived the job. It is the language of your financial statements, your year-end review, and any honest answer to "was that job worth doing?"
The bridge between them is one formula worth taping inside your clipboard:
Markup needed = margin wanted ÷ (1 − margin wanted)
Want a 30 percent margin? 0.30 ÷ 0.70 = 42.9 percent markup. Want 40? 0.40 ÷ 0.60 = 66.7 percent markup. Going the other way: margin = markup ÷ (1 + markup), which is how you translate a competitor's bragged-about markup into what they actually keep.
Two sanity rails that fall out of the math: margin can never reach 100 percent no matter the price, and a markup of X percent never produces a margin of X percent. If your spreadsheet ever shows otherwise, the spreadsheet is wrong.
Estimated margin is not realized margin
There is a second layer to this once the vocabulary is fixed: the margin you priced is not the margin you made.
You priced the job at $12,000 against $10,000 of expected cost: 16.7 percent. Then the tile order needed a second batch, the demo found ductwork where the plans said none, and your best guy spent half a day waiting on an inspection. Actual cost: $10,900. Realized margin: $1,100 ÷ $12,000 = 9.2 percent. The estimate said one thing; the job did another, and the difference is where estimating actually improves, if you ever see it.
Most contractors never see it, because seeing it requires the job's real costs in one place: labor hours at loaded cost, every material receipt, every sub invoice, matched against what was billed. Kept in a head or a glovebox, that reconciliation never happens, and every future estimate inherits the same blind spots.
This is precisely what a job profitability report is for. In Zeus, time tracked against the job, receipts scanned to it, and the invoices billed from it roll up into realized margin per job. So "that bathroom made 9 percent, not 17" is a fact you learn in February of this year, not a mystery your accountant hands you in April. A few jobs of that feedback and your markups stop being folklore; they become corrections.
Making the fix stick
One habit locks it in: pick one language for internal use and translate at the border. Most contractors do best thinking in markup day to day (it matches how prices get built) while keeping a taped-up conversion table for the rooms where margin is spoken. What ruins businesses is not choosing the "wrong" word. It is drifting between the two without noticing, so that the number in the estimate, the number in the budget, and the number in the year-end review were never the same number.
The five-minute version of everything above:
- Decide the margin your business needs: from overhead, owner's pay, and profit, not from a rumor.
- Convert it once: markup = margin ÷ (1 − margin). Write that markup down.
- Price jobs with the markup. Judge jobs with the margin.
- Check realized margin per job, and adjust the markup when reality disagrees with the estimate.
The contractor from the April meeting did exactly this. His fix was one line: the 20 percent markup became 25. On his volume, that was the missing fourteen thousand dollars back: not from working harder, not from a single new client, but from finally charging the number he thought he was charging all along.
Frequently asked questions
Is a 20% markup ever enough?
For a pure pass-through (materials you resell with no handling, storage, or risk), possibly. As the whole-business number, almost never: a 20 percent markup is a 16.7 percent gross margin, and for most trades that will not cover overhead and leave a real profit. Most healthy small trade businesses need gross margins well north of that, which means markups of 40 percent and up on the work itself. Derive yours from your own costs rather than adopting anyone's rule of thumb, including that one.
Should I use the same markup on materials, labor, and subcontractors?
Many contractors run tiers: a higher markup on labor (where the risk and management burden lives), a moderate one on materials, and a lower one on subcontractor quotes (where the sub carries much of the risk but you still carry warranty and coordination). Tiers are fine. What matters is that the blended result hits your target margin. Check it on real jobs rather than assuming.
Do I tell clients my markup or margin?
On fixed-price work, neither: you quote a price for a scope, and the internals are yours. On cost-plus or time-and-materials contracts, the markup is part of the deal and must be stated precisely. Those contracts are exactly where writing "20% margin" while meaning "20% markup" turns into a genuine dispute, because on $100,000 of cost the two words differ by $5,000.
My gross margin looks fine but there is still no money at year end. Why?
Gross margin only covers what jobs earn above their direct costs. Below it sits overhead (truck, insurance, phone, software, the unbillable half of your week) and below that, net margin. Healthy gross with an empty account usually means overhead is eating the gross, or unbilled hours are hiding inside "labor cost." Split the two questions: are jobs priced right (gross), and is the business lean enough (net)? They have different fixes.
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