Payment fees, pricing, everyday math, electrical sizing and energy cost — each with the formula, the assumptions and a worked example.
Browse All CalculatorsEnter a cost plus a markup, a target margin or a selling price — get the other numbers, including the markup-versus-margin difference that trips people up.
See exactly what PayPal takes from a payment and what lands in your account — or work backwards to the amount you should charge.
Add values and their weights — grades and percentages, prices and quantities, scores and credits — and get the weighted average with the working shown.
Find the minimum copper or aluminum conductor for a load, checking both ampacity (NEC Table 310.16) and voltage drop over your run length.
Flat or tiered commission, with an optional split and base pay — see what a deal or a month of sales actually pays you.
Work out Stripe's cut of a card, in-person or ACH payment — including international and conversion surcharges — or the amount to charge to net a target.
Payment fees, pricing, markup, commission and food cost.
Wire size, amps, watts and electricity cost.
API cost, payload size, performance and cloud tools for engineers.
Every calculator shows the formula it uses and works through real examples.
Fee schedules and code tables name their source and the date we last checked them.
Each page says what it assumes and what it does not model, so you know when to dig deeper.
Calculations run in your browser. No account, no paywall.