What you'll find here
- Basic Calculator — a full calculator with keyboard support, right on the homepage.
- BMI Calculator — body mass index with healthy weight range, metric or imperial.
- Percentage Calculator — three percentage tools side by side.
- Loan Calculator — payments, total interest and a year-by-year balance table.
- Compound Interest — savings growth with monthly contributions.
- Age Calculator — exact age and next-birthday countdown.
- Tip Calculator — tip and bill splitting that updates as you type.
- Unit Converter — length, weight, temperature and volume.
Private by design
Every calculation happens in your own browser. Nothing you type is sent to a server, stored, or shared — close the tab and it's gone. The math uses standard published formulas, noted at the bottom of each calculator page.
Why we built CalculatorWorks
Most of us hit the same handful of number questions again and again — splitting a bill, checking a loan payment, converting a recipe, working out a percentage off. Search for any one of them and you'll often land on a page buried under pop-ups, cookie walls, and three screens of filler before the actual calculator appears. We wanted the opposite: a small, fast, honest set of tools that give you the answer and then get out of the way.
Every calculator here is built around a single clear job. Type your numbers, get the result, and if you're curious, read the plain-English explanation and worked example below each tool. No app to install, no account to create, no data leaving your device.
How we keep the numbers right
Each tool uses the standard, published formula for its job — the WHO categories for BMI, the amortization formula for loans, monthly compounding for savings growth, and the official conversion factors for units. The formula behind each calculator is written out on its page so you can check the working yourself rather than taking a black box on trust. Where a result depends on custom or context — like tipping norms or investment returns — we say so plainly, because a calculator should inform a decision, not pretend to make it for you.
Get in touch
Spotted a mistake, or want a calculator we don't have yet? We'd genuinely like to hear it. Email petshoppawsandwhiskers@gmail.com and we'll read it. Suggestions for new tools are what shape what we build next.