Fraction Calculator
Exact arithmetic on fractions and mixed numbers. Useful for cooking, woodworking, sewing.
Runs entirely in your browser. Nothing is sent to our servers.
About this tool
Performs exact arithmetic on fractions and mixed numbers. Unlike a regular calculator, results are kept as fractions (3/4, 7/8) rather than rounded decimals (0.75, 0.875). Useful for cooking, woodworking, sewing — anywhere fractions are the natural way to express a measurement.
Syntax
- Simple fractions:
1/2,3/8,-7/16 - Whole numbers:
5(treated as5/1) - Mixed numbers:
2 1/3(whole and fraction separated by a space) - Operators:
+,-,*(or×),/(or÷) - Parentheses:
(1/2 + 1/4) * 2
Operator precedence is standard: multiplication and division before addition and subtraction. Use parentheses to override.
Output
Each result is shown three ways:
- Simplified fraction (e.g.
5/6) - Mixed number if the value is greater than 1 (e.g.
1 2/3) - Decimal equivalent rounded to 6 places (e.g.
0.833333)
Frequently asked questions
- How are fractions simplified?
- By dividing the numerator and denominator by their greatest common divisor. So 6/8 becomes 3/4. Negative fractions show the sign on the numerator: −3/4, not 3/−4.
- Can I do something like 5/8 inch + 1/16 inch?
- Yes — the calculator doesn't care about units. Just enter
5/8 + 1/16and you'll get 11/16 (the unit is implied by your problem). For dimensional analysis with mixed units, see the Length Converter. - Why does the tool show "1 2/3" instead of "5/3"?
- For values greater than 1, mixed numbers are usually more intuitive — "1 cup and 2/3" is easier to picture than "5 thirds of a cup". Both forms are shown.
- Is there a precision limit?
- Integers are limited by JavaScript's safe integer range (about 9×10^15). For most everyday fraction work — woodworking, baking, music theory — this is more than enough. For very large numerators or denominators, results may overflow.
Last updated: May 17, 2026