About PlainCalc

PlainCalc is a small collection of free calculators for everyday questions: payments, percentages, dates, health numbers, school grades and unit conversions.

How the calculators are checked

Every calculator uses a published, standard formula, shown on its page. The math is covered by automated tests against known reference values (for example, a $200,000 loan at 6% over 30 years must come to $1,199.10 a month) and the tests run before every update.

Privacy first

The calculations run entirely in your browser. We don't have accounts, and we never receive what you type. See the privacy policy.

Not advice

Results are estimates for information. For decisions about money, health or law, talk to a qualified professional.