Subtracting Fractions Calculator

Last updated: June 2026

Fraction 1

Numerator/Denominator

Fraction 2

Numerator/Denominator

Difference

1/12

Mixed number

1/12

Decimal

0.083333

Step-by-step working

Find the LCD of 3, 4: 12.
1/3 = 4/12.
1/4 = 3/12.
Combine numerators: 4 - 3 = 1.
Answer before simplifying: 1/12.
Simplified answer: 1/12.

About this calculator

The Subtracting Fractions Calculator subtracts fractions step by step. It handles unlike denominators by finding the LCD and is useful for checking homework, measurements, and mixed fraction subtraction.

subtracting fractions calculator method

To subtract fractions, convert them to a common denominator, subtract the numerators in order, then simplify the result.

LCD = LCM of denominators
a/b - c/d = converted first numerator / LCD - converted second numerator / LCD
difference = numerator difference / LCD

How to use the subtracting fractions calculator

Enter the starting fraction.
Enter the fraction or fractions to subtract.
Find the LCD.
Convert each fraction to the LCD.
Subtract numerators from left to right.
Simplify the answer.

Worked examples

Subtract unlike denominators

Input: 3/4 - 1/3

Calculation: LCD = 12; 9/12 - 4/12

Result: 5/12

Mixed-number style result

Input: 13/4 - 7/4

Calculation: 6/4 simplifies to 3/2

Result: 1 1/2

Order matters

Subtraction is not commutative. 3/4 - 1/3 gives a different result from 1/3 - 3/4.

Negative answers

If the fraction being subtracted is larger than the starting fraction, the result will be negative.

Learning and homework note

This calculator is for learning, checking, and general educational use. It shows the method so students can compare each step with their own working, but it should not replace learning the underlying fraction rules.

Check that every denominator is not zero.
Negative fractions can be written in more than one equivalent form.
Rounding may affect decimal or percentage displays.

Frequently asked questions

Does this show the working?

Yes. The fraction calculators are designed to show the main steps, not just the final answer.

Does it simplify answers?

Yes. Fraction answers are reduced to lowest terms where simplification is part of the method.

Can denominators be zero?

No. A denominator of zero is undefined in fraction arithmetic.

Can I use negative fractions?

Yes, but pay attention to signs. The calculator normalises signs so the denominator stays positive.

Why might my teacher write the answer differently?

Equivalent fractions and mixed numbers can represent the same value. Check whether the question asks for improper fraction, mixed number, decimal, or simplest form.

Related calculators

Fraction Calculator
LCD Calculator
Mixed Number Calculator

What does this mean?

This calculator is designed to help you understand the likely number before you make a decision or start an application.

Your result should be checked against official UK guidance, especially if your circumstances include dependants, exemptions, prior leave, or a complex immigration history.

Treat the figure as a planning tool rather than legal advice. Where the answer affects an application deadline or major payment, speak to an authorised adviser.