Money maths you can check yourself.

Why these are calculators and not answers

A calculator that only prints a total is asking to be trusted. A calculator that shows the monthly payment, the interest split, and the balance after five years lets you decide whether the number is plausible. Every tool in this group shows its working, because the money questions people actually have are rarely just “what is the number” — they are “is this number right, and what happens if I change one thing”.

Bills, tips and discounts

Splitting a bill is the most common one, and the one most likely to go wrong in a group chat. TipSplit takes a total, a party size and a tip percentage, then gives a per-person figure you can screenshot. It handles the two things that break naive division: an uneven split when one person did not drink, and rounding up so the total lands on a clean number.

Discount Calculator answers the reverse question too — not just “30% off what?” but “this is now $68 from $95, what discount is that actually?”. Retailers quote the number that looks best; this tells you the one that is true. Percent Calculator covers the plain percentage cases that come up at work: X% of a number, what percent one number is of another, and percent change between two figures.

Loans, mortgages and what they really cost

The monthly payment is the number lenders advertise, and it is the least informative one. Loan Calculator shows the payment alongside total interest and the full amount repaid, which is where the difference between a 5-year and a 7-year term becomes visible. Mortgage Calculator adds the payoff date and the effect of one extra payment a month — usually a year or more off the term, and a five-figure sum in interest.

Saving, pay and retirement

Compound Interest separates the money you put in from the money the interest put in, which is the only way to see when compounding starts to matter. Salary Converter moves between hourly, weekly, monthly and yearly, useful when a job advert quotes one and you think in another. Retirement Calculator projects a balance forward and then discounts it back to today’s money, because a number thirty years out is meaningless without that adjustment.

What these are not

They are arithmetic, not advice. No tool here knows your tax bracket, your local mortgage rules, or whether your employer matches contributions. Treat the output as a well-checked estimate and take the final decision to someone qualified — or at least to a spreadsheet you built yourself.

Questions