Calculators for real decisions
People use calculators before decisions that matter: whether a mortgage payment fits a budget, how much a savings plan will grow, what an hourly rate means as a yearly salary, when a baby is due, or how many days are left before a deadline. The calculators here are built for those moments, with sensible defaults so you see a meaningful result immediately and change only the numbers that are yours.
They are grouped into finance, health, dates and time, school, and math and units.
Other calendars and year charts
The calendar converter turns a date into twelve other calendars at once: Japanese era, Islamic Hijri (Umm al-Qura or tabular), Persian Solar Hijri, Thai Buddhist Era, Minguo, Chinese and Korean lunar, Nepali Bikram Sambat, Ethiopian, Hebrew, Indian Saka and Coptic, in both directions. Its pages for Japanese era, Hijri, Persian, Thai, Minguo, Nepali, Ethiopian and Chinese zodiac dates each carry a year chart, such as Nowruz dates, Ramadan and Eid dates, or a wareki chart with ages and school graduation years.
Tax on prices and invoices
The VAT calculator adds VAT, GST or sales tax to a net price or takes it out of a gross one, with the standard and reduced rates of 79 countries and all 50 US states, and splits India's GST into CGST and SGST. Each rate shows the date it was checked and links to its source, and invoice lines total mixed rates the way an invoice does.
How results are calculated
Every calculator shows the formula it uses and explains its assumptions, such as whether interest compounds monthly or daily, or which BMI categories apply. Finance calculators produce full schedules you can export, so you can check any month yourself. Results are estimates for planning: lenders, doctors and schools may use slightly different rules, and the pages say where that is likely.
Numbers and dates follow the format of your device's language, and money calculators work in any currency.
Shareable and private
Your inputs never leave your device; the arithmetic runs in the page. Where it is useful, the current inputs are kept in the page address so you can bookmark a calculation or send it to someone, and they will see the same numbers. Nothing is stored on a server and you don't need an account.
Using the results well
Treat the results as a starting point for a conversation with a lender, doctor or school rather than a final answer, and check the assumptions panel when a number looks surprising. Small inputs matter: a quarter of a percentage point on a 30-year loan, or an extra hour a week in a salary conversion, changes the result more than people expect. Every calculator keeps working offline once the page has loaded.