💰 Free Finance & Crypto Calculators
Three calculators for the numbers that are easy to get wrong in your head: what compounding actually does over ten years, what a trade returned once fees are counted, and what a given prompt costs across the major AI models. Estimates for planning — not financial advice.
Percentage Calculator
Percentage change, discounts, VAT, working backwards from a total, and what a headline return actually means per year.
Compound Growth & Crypto Staking Calculator
Project compound interest, savings growth, and crypto staking returns over time.
Crypto Profit & ROI Calculator
Calculate your crypto profit, loss, and ROI from buy and sell price, including trading fees.
AI Token & Cost Calculator
Estimate tokens and API cost, input and output, across GPT-6, Claude, and Gemini, with dated official prices.
Crypto DCA Calculator
See what buying the same amount of Bitcoin, Ethereum or Solana every month would be worth today, from real monthly closing prices.
Crypto Gains & Tax Estimator (FIFO)
Realized gain or loss on crypto sales with the FIFO method, fees included, and an estimated tax at your own rate.
Trading Fee & Spread Calculator
Compare what fees and spreads really cost per trade and per year on up to three platforms.
AI Subscription vs API Cost Calculator
Is a flat AI subscription or pay-per-use API cheaper for the way you use it? With dated official prices.
Loan Payment Calculator
Monthly payment, total interest and total cost of a fixed-rate loan.
Inflation & Purchasing Power Calculator
What things will cost in the future, and what your money will really be worth, at a given inflation rate.
How to get the most out of these
Three calculators, one shared principle: show the arithmetic people skip. Compounding is unintuitive over long spans, fees on both sides of a trade eat more than the headline suggests, and AI token costs only feel small until multiplied by a batch job. Each calculator makes the skipped step visible as a number.
Read all three the same way: the math is exact, the assumptions are not. The compound calculator holds a rate steady for years, which no market does; the crypto calculator models one clean trade without slippage or tax; the token calculator estimates tokens without the model's real tokenizer. The pages state their own gaps - use the results as planning sketches with known edges.
None of this is financial advice, and everything runs in your browser - amounts, trades, and prompts stay on your machine.