Fraction Calculator

How to use the fraction calculator

1. Choose Add, Subtract, Multiply or Divide for two numbers, or Simplify for one number.
2. Enter an integer such as -3, a fraction such as 3/4, or a mixed number such as -2 1/3. Use ordinary digits, an ASCII slash and a space between a mixed number's whole and fractional parts.
3. Read the result in lowest terms. An equivalent mixed number is also shown when the answer is an improper non-integer fraction.
4. Open Calculation and decimal equivalent to check how the answer was found. Copy keeps the exact result and any qualified decimal equivalent together; Clear starts a new blank addition.

What this tool includes

• Addition, subtraction, multiplication and division of two numbers, plus an explicit one-number Simplify operation.
• Signed integers, proper and improper fractions, and mixed numbers with a clearly defined leading sign.
• An exact result reduced to lowest terms, with a positive denominator and a conditional mixed-number equivalent.
• A compact method showing the interpreted fractions, the unreduced result and the common factor removed.
• A decimal equivalent inside Details, with rounding and very small nonzero results clearly qualified.

When this is useful

• Check fraction arithmetic for a lesson, exercise or a manually worked calculation.
• Combine or scale numerical amounts already expressed in the same unit, such as fractional recipe quantities or measurements, without converting between units.
• Reduce one fraction or convert between its improper and mixed-number forms without entering an unnecessary second number.

Understanding fraction arithmetic

A fraction has an integer numerator and a nonzero integer denominator. This tool accepts a negative sign in either part of a simple fraction and puts any final sign in the numerator; for example, 1/-2 is -1/2.

A mixed number combines a whole part with a proper fractional part. A single initial minus applies to both parts: -2 1/3 means -(2 + 1/3), while -0 1/2 means -1/2. The fractional numerator may be zero but must be smaller than its positive denominator.

For addition and subtraction, give both fractions a common denominator and combine their numerators in the selected order. This calculator uses the denominator product; that is a valid common denominator, not necessarily the least one.

For multiplication, multiply the numerators and denominators. For division, multiply the first fraction by the reciprocal of the second. A zero second number cannot be used as a divisor, even if the first number is also zero.

The result is reduced by dividing the numerator and denominator by their greatest common divisor. A denominator of 1 is written as an integer and a zero result as 0. An improper non-integer result also has an equivalent mixed form.

The exact fraction is never rounded. Only the decimal equivalent in Details uses up to six decimal places, with halfway values rounded away from zero. About marks a rounded decimal. A nonzero magnitude below 0.000001 is shown as a strict signed interval instead of a false zero.

Fraction calculation examples

Add 1/2 and 1/3: (1 × 3 + 1 × 2)/(2 × 3) = 5/6. The decimal equivalent is About 0.833333; 5/6 remains exact.

Subtract 1/6 from 3/4: (3 × 6 - 1 × 4)/(4 × 6) = 14/24 = 7/12.

Multiply 2/3 by 9/4: 18/12 reduces to 3/2, also written as 1 1/2.

Divide 3/4 by 2/5: 3/4 × 5/2 = 15/8, also written as 1 7/8.

Simplify 42/56 by dividing both parts by 14 to obtain 3/4. For a signed mixed example, -2 1/3 - 1/6 gives -5/2, or -2 1/2.

Input rules and limits

Each active number is limited to 64 UTF-16 text units before trimming. Each entered integer, whole part, numerator or denominator has absolute value at most 1,000,000,000. The result may legitimately have larger integer components.

Use ASCII digits 0–9, + or - signs and /. Surrounding ASCII whitespace and ordinary spaces around a slash are allowed. A mixed number uses one or more ordinary spaces between its whole and fractional parts; signs inside that fractional part are not allowed.

Decimal inputs, thousands separators, exponents, percentages, units, formulas, Unicode fraction glyphs and non-ASCII minus signs are unsupported. Write 1/2 rather than ½. Invalid input is not guessed, silently shortened or partially calculated.

Changing between the four arithmetic operations retains both drafts. Selecting Simplify discards the second draft and returning to arithmetic leaves it blank. This tool does not solve multi-step expressions, compare fractions, convert measurement units or provide decimal-input conversion modes.

Your calculation and copied result

The calculator works in page memory without an account, upload, saved history or input-bearing share URL. Inputs and calculated output use the site's existing private-content markers.

Copy sends a checked summary to your clipboard only on request, or offers a selected read-only field when automatic copying is unavailable. This tool-specific behavior is not whole-site or third-party privacy certification.