Subtracting Fractions Calculator

Work out subtracting fractions instantly with clear inputs, formula shown and shareable results.

About Subtracting Fractions Calculator

Subtraction mirrors addition: put both fractions over the common denominator bd and subtract the numerators, giving (ad − cb)/bd, then reduce.

Formula

Subtracting fractions

a/b − c/d = (ad − cb) / bd

Worked example

With the default values below, Subtracting Fractions Calculator returns Difference in lowest terms of 7/12. Change any input above and every figure here is recalculated in your browser.

Inputs used

First numerator: 3
First denominator: 4
Second numerator: 1
Second denominator: 6

Results

Difference in lowest terms: 7/12
As a mixed number: 7/12
Decimal value: 0.58333333
Lowest common denominator: 12

Step by step

1Values used
2Subtracting fractions
3Difference in lowest terms= 7/12
4As a mixed number= 7/12
5Decimal value= 0.58333333
6Lowest common denominator= 12

Assumptions and limits

The result is derived only from the 4 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation, tax, fees or charges or compounding frequency into account.
Figures are rounded for display to 8 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

What is 3/4 − 1/6?

(18 − 4)/24 = 14/24 = 7/12.

What if the result is negative?

That is fine; the sign is carried on the numerator and the reported fraction keeps a positive denominator.