Finance Tools

This category covers everyday financial math that's simple in principle but easy to get subtly wrong under time pressure — splitting a bill and tip fairly among a group, working out a loan's full amortization schedule instead of just the monthly payment, calculating ROAS with your actual cost of goods factored in rather than a raw revenue-over-spend number that overstates profitability, and projecting compound interest over years with contributions added along the way. The Loan & Insurance Calculator produces the full payment breakdown — principal versus interest per period — which matters if you're comparing two loan offers with different terms rather than just different monthly numbers. The ROAS Calculator exists specifically because a 4x return looks identical to a 4x return on paper whether your margin is 60% or 8%, and the difference between those two situations is the difference between a profitable campaign and a loss.

None of these calculators require an account or store your numbers anywhere — the loan amount, your margins, your bill total stay in the browser tab and disappear when you close it, which matters for numbers you'd rather not hand to a server you don't control, even a fairly innocuous one — a real ad budget, a client's loan terms, a margin you haven't shared with anyone else yet.