Fraction and Ratio Calculator

1. Choose Fraction arithmetic, Simplify a ratio, or Solve a proportion.
2. Enter values in First value and Second value, Ratio, or the fields labeled a, b, c, and d.
3. Choose an Operation, or choose the proportion type and the value to solve for.
4. Select Calculate. Use Copy result or Download result (.txt) to keep the text output.

Fraction arithmetic with mixed numbers

Fraction arithmetic accepts whole numbers, decimals, fractions, and mixed numbers. In Operation, choose + Add, − Subtract, × Multiply, or ÷ Divide. A value can start with a minus sign. A denominator of zero is rejected, and the second value cannot be zero when you choose ÷ Divide.

First value: 1 3/4
Operation: + Add
Second value: 5/8
Exact result: 19/8
Mixed number: 2 3/8
Decimal: 2.375

Result contains Exact result, Mixed number, and Decimal. A repeating decimal can appear in parentheses, such as 0.(3). Steps also show the conversion and arithmetic used for the selected operation.

How to simplify a ratio

Enter at least two terms in Ratio. Separate them with colons, commas, or whitespace, using one separator style: 8:12:20, 8,12,20, or 8 12 20.

Ratio: 8:12:20
Simplified ratio: 2 : 3 : 5

Each term can be a whole number, decimal, or fraction. The calculator clears fractional terms before reducing the ratio. Negative terms and an all-zero ratio produce errors. Mixed colon-and-comma input and slash-only input such as 8/12 are rejected. Steps include each term's decimal share, with an ellipsis when the displayed value is truncated.

How to solve a direct or inverse proportion

In Solve a proportion, choose Direct proportion (a/b = c/d) or Inverse proportion (a × b = c × d). Then choose Solve for a, Solve for b, Solve for c, or Solve for d, and fill in the other three values. Whole numbers, decimals, fractions, and mixed numbers are accepted.

Direct proportion (a/b = c/d)
a = 2, b = 3, c = 10
Solve for d: d = (3 × 10) / 2 = 15

Direct mode uses cross-multiplication. Inverse mode keeps the two products equal. A zero required divisor, or a zero that leaves the selected value undetermined, produces an error. The result gives the solved value as an exact fraction, a mixed number when applicable, and a decimal.

What Steps shows

• Fraction arithmetic shows entered-value conversions, the operation, simplification, and the decimal equivalent.
• Ratio reduction shows fraction clearing when needed, the greatest common divisor step, and decimal shares.
• Proportion solving shows the selected equation, the formula for the unknown, and the resulting forms.

When another math calculator fits better

Use the Fraction Calculator to simplify one fraction or run a chain of fraction operations. Use the Ratio Calculator for a missing term in an equivalent ratio or for dividing a total by a ratio.

Use the Proportion Calculator when the job is specifically a missing value in a direct or inverse proportion. For equations, sequences, geometry, and other calculation types, browse Math Calculators.

Frequently asked questions