Our mission
About CalcFolks
We build calculators that give you the answer and show how they got there, so you can check the math yourself.
What we do
CalcFolks is a library of free online calculators, unit converters and small tools. The build list currently covers 410 tools in English, Spanish and Portuguese, across 11 categories from dates and money to home projects and science.
Who it’s for
- Everyday questions: what date is 90 days from now, how many cups in a liter, what a loan really costs.
- Work: estimating materials, converting units on a spec sheet, checking a payment schedule.
- Study: formulas with steps, worked examples and reference tables.
Why we built it
Many calculator sites give a number with no explanation, bury it under ads, or hide the assumptions that change the answer. We think a calculator should be as easy to verify as it is to use. So every tool shows its formula, a worked example, its assumptions and its sources, and the same tools are available in English, Spanish and Portuguese.
How we design calculators
- Start from the question people ask. Our tool list comes from search research, so each page answers a question people actually have.
- One clear form. Plain labels, sensible defaults, units you can switch and instant validation.
- Results you can read. The main answer first, then supporting values, the formula and a step-by-step breakdown.
- Different tools, different layouts. A date tool shows a calendar; a loan tool shows a schedule and chart.
How tools are researched and tested
Each live tool uses a documented formula with stated units and assumptions (see our calculation methodology). Formulas are covered by automated tests with known answers, for example a $200,000 loan at 6% for 30 years must give a $1,199.10 monthly payment.
Tools that affect money or health are reviewed by a qualified person before they go live. Their name and credentials appear on the page once verified.
Our commitments
- No sign-up needed to use any tool.
- Calculations run in your browser; we don’t need your inputs to show results.
- We clearly mark estimates and say when to ask a professional.
- We correct mistakes quickly and note significant changes on the page.
Read our editorial policy and meet the editorial team.
Contact us
Spotted an error, or need a tool we don’t have? Get in touch, report a calculation error or request a tool.