Business
ROI, profit margin, and business calculators — 14 free tools available. No signup required.
Margin, markup, ROI, break-even, payment processor fees and the marketing metrics that get quoted in meetings: mostly small calculations that are easy to get subtly wrong.
Two of them are wrong in the same way constantly. Margin and markup are different numbers computed from different denominators, and using one where the other belongs silently misprices a product. Processor fees have a fixed component that makes the effective rate on small transactions far higher than the headline percentage suggests.
Everything runs in your browser. Revenue figures, costs and customer numbers stay on your device.
Where to start
- Profit Margin Calculator — Margin on revenue, kept clearly distinct from markup on cost.
- Markup Calculator — The other direction, with the conversion between the two shown.
- Breakeven Point Calculator — Units and revenue needed to cover fixed costs, using contribution margin.
- Stripe Fee Calculator — Includes the fixed per-transaction component, which dominates on small payments.
- A/B Test Significance Calculator — Reports statistical significance rather than declaring a winner from a raw difference.
All business (14)
Profit Margin Calculator
A profit margin calculator for gross margin, markup, net profit and breakeven, plus the exact price that hits a…
Invoice Generator
Create invoices online with line items, tax and a currency symbol of your choice. Print or save to PDF.
Discount Calculator
A discount calculator for stacked "extra % off" deals that compound rather than add, sales tax, and both reverse…
UTM Campaign URL Builder
Build custom campaign tracking URLs with standard UTM parameters for Google Analytics, Meta Ads, TikTok, and…
Breakeven Point Calculator
A breakeven calculator for units and revenue from fixed costs and contribution margin, plus margin of safety and…
Return on Investment (ROI) Calculator
Calculate return on investment and the annualized rate that makes different holding periods comparable.
PayPal Fee Calculator
A PayPal fee calculator for goods and services (3.49% + $0.49) and friends and family, the 1.5% international and…
Stripe Fee Calculator
Calculate Stripe credit card processing deductions (2.9% + 30¢), international card fees, and net payout revenue.
Markup Calculator
Calculate retail selling price, dollar profit, and understand the difference between Markup % and Gross Profit…
CPM (Cost Per Mille) Calculator
A CPM calculator that solves all three ways: cost per thousand impressions from a bill, the budget for a reach…
A/B Test Significance Calculator
An AB test calculator for significance: p-value, Z-score, the confidence interval on the difference, observed…
Freelance Hourly Rate Calculator
A freelance rate calculator for hourly and day rates from your take-home target, overheads, tax and billable…
Time Card Calculator
A weekly time card calculator with clock in/out, unpaid breaks, overnight shifts, hourly pay, and FLSA overtime.
Conversion Rate Calculator
A conversion rate calculator that computes your rate from visitors and conversions, and works backwards to show…
Margin and markup are not the same number
Margin is profit as a share of the selling price; markup is profit as a share of the cost. An item costing 60 and selling for 100 carries a 40% margin and a 66.7% markup: the same 40 of profit measured against two different bases. Applying a 40% markup when you meant a 40% margin produces a selling price of 84 rather than 100, and the shortfall is invisible unless someone checks. In businesses that price on cost and report on revenue, both numbers are in use simultaneously, which is precisely how the confusion survives.
The fixed fee is what makes small transactions expensive
Payment processors typically charge a percentage plus a fixed amount per transaction. On a large payment the fixed component is negligible and the effective rate is close to the headline percentage. On a small one it dominates: a fixed fee of thirty cents on a two-dollar sale is fifteen percent before the percentage is applied at all. This is why micro-transactions are hard to make work, why minimum order values exist, and why batching several small charges into one is worth the friction where it is possible.
A difference is not a result
An A/B test showing 4.2% against 3.8% has produced a difference. Whether it has produced a finding depends on the sample size, and with small numbers of conversions a gap that size is entirely consistent with chance. Calling a winner early is the most common way online testing produces confident nonsense, and repeatedly checking a running test until it looks significant makes it worse, because each look is another chance for noise to cross the threshold. Decide the sample size before starting and check once.
Lifetime value is an assumption wearing a number
Every LTV calculation rests on an assumed churn or retention rate, and the output is extremely sensitive to it: small changes in monthly churn produce large changes in lifetime value, because the relationship is not linear. That makes LTV useful for comparing scenarios and unreliable as a precise figure, particularly for a young business with too little history to know its real churn. The number is worth computing; the confidence people place in three significant figures of it usually is not.
Frequently asked questions
What is the difference between margin and markup?
Margin measures profit against the selling price; markup measures it against cost. The same profit gives a lower margin percentage than markup percentage. Our calculators convert between the two.
Are the processor fee figures current?
Each fee calculator states the rate it uses and when it was checked. Processors change pricing and it varies by country and product, so confirm against your own account before relying on a figure.
Is my business data stored?
No. All of these run in your browser. Revenue, costs and customer figures never leave your device.
How large should an A/B test be?
It depends on your baseline rate and the smallest difference worth detecting. The calculator reports significance for the numbers you have; decide the required sample before you start rather than watching until it looks convincing.
Is this accounting or tax advice?
No. These are arithmetic tools. Anything with tax or regulatory consequences should go to a qualified accountant.