Free Online Calculator & Percentage Calculator

Yes. Every calculator on this page is free to use, with no sign-up and no limits.

It works like a phone calculator. When a percentage directly follows + or −, it is taken of the number before it: 200 + 10% = 220 and 200 − 10% = 180. Everywhere else b% simply means b ÷ 100, so 200 × 10% = 20 and 50% on its own is 0.5.

Brackets first, then powers (xʸ, evaluated right to left, so 2^3^2 = 2^9), then multiplication and division, then addition and subtraction, from left to right. A leading minus applies after the power: −2^2 = −4. Unclosed brackets are closed automatically when you press =.

Computers store decimals in binary, which makes 0.1 + 0.2 come out as 0.30000000000000004. Zebra Calc removes this noise: additions and subtractions that cancel out give exactly 0 (so 0.1 + 0.2 − 0.3 = 0), and results are shown with up to 12 significant digits, which is plenty for everyday use. Whole numbers up to 15 digits are shown exactly.

Yes. You can type 2.5 or 2,5 everywhere. In the percentage, discount, tip, unit and date fields, thousands separators such as 1 234,5, 1.234,5 or 1,234.5 are recognised too. A single comma or dot is read as the decimal separator, except when it is followed by exactly three digits and is the thousands separator of your browser’s language: with English settings 1,299 means one thousand two hundred ninety-nine, with German settings 1.299 does. The result sentence always shows how a number was read. In the main calculator a comma is always the decimal point, so leave out thousands separators there; it shows a dot so the expression stays unambiguous.

Percentage change = (new − old) ÷ |old| × 100. Going from 80 to 100 is a 25% increase, and from 100 to 80 a 20% decrease. A change starting from 0 cannot be expressed as a percentage, so the calculator shows the absolute difference instead.

Decimal units use powers of 1000: 1 MB = 1,000,000 bytes. Binary units use powers of 1024: 1 MiB = 1,048,576 bytes. Drive makers use decimal units, while some operating systems report binary units, which is why a 1 TB drive shows up as about 931 GiB.

Whole months are counted first and the remaining days after that. When a month is shorter, the date moves to its last day, so 31 January plus one month is 28 February (29 in a leap year), and 31 January to 28 February is 28 days rather than a full month.

In years without 29 February, Zebra Calc counts the new year of age from 1 March. Some countries use 28 February for legal purposes, so check local rules if the exact day matters.

No. All calculations happen in your browser. Your numbers, dates and history are never uploaded, and the history disappears when you close the page.