Free business calculators

Each answers one real question, computed in your browser, no account needed. Marketplace fees come prefilled with their source and effective date — adjust them to your own contract.

Selling and ads

Amazon, Shopify, eBay and Etsy fee profit calculatorEnter price and cost, pick a marketplace: referral, payment and order fees are prefilled from the published schedule, every line editable.Discount break-even calculator: how many more orders a sale needsHow many more orders keep the same profit after a discount — with a warning when the discount makes every order lose money.ROAS, CAC, LTV and ad payback calculatorDo the ads pay: ROAS against break-even ROAS for your margin, CAC, gross-profit LTV and the LTV:CAC ratio.Price elasticity of demand calculatorFrom two prices and volumes, see whether raising the price lifts or cuts revenue, and the expected revenue at a new price.

Loans and investment

Business loan amortization calculatorLevel payments or equal principal: the payment each month, total interest and the full schedule.NPV, IRR and payback period calculatorEnter the investment and yearly cash flows: NPV, IRR, simple and discounted payback.CAGR calculator with growth projectionAverage yearly growth between two points, a projection ahead and the time to double.

Operations

EOQ, reorder point and safety stock calculatorHow much to order each time, when to reorder, and the safety stock for a service level.Profit driver tree: which lever moves profit mostBreak profit into customers, frequency, order value and margin, and see which improvement pays most.

Risk and statistics

Profit sensitivity analysis (tornado chart)Move each driver ±10% and rank which one moves profit the most.Monte Carlo profit simulationThousands of scenarios at once: P5, P50 and P95 profit and the chance of a loss.A/B test significance and sample size calculatorIs B really better than A: p-value, confidence interval and the sample needed for the lift you care about.