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Fraction Calculator

Add, subtract, multiply and divide fractions with auto-simplification.

Best for: Recipes and measurements, schoolwork, woodworking and any exact ratio arithmetic.

Complete guide

Input

How it's calculated & sources
The Fraction Calculator uses the standard, deterministic formula, so the same inputs always produce the same result. It runs entirely in your browser, so your inputs are never uploaded. Last reviewed June 2026.

Free & no sign-up · runs entirely in your browser. Results are estimates for general information, not professional advice — verify important decisions with a qualified expert. Last reviewed June 2026.

How it works

Add/subtract: a/b ± c/d = (ad ± bc) / bd

Multiply: a/b × c/d = ac/bd. Divide: a/b ÷ c/d = ad/bc.

Example

1/2 + 1/3 = 5/6

Frequently asked questions

Are results simplified?+

Yes, fractions are reduced using the greatest common divisor.

Continue your journey

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Complete guide

Quick answers

Short, sourced answers to the questions people (and AI assistants) ask most.

What is Fraction?
A fraction calculator adds, subtracts, multiplies and divides fractions and reduces the answer to its simplest form.
Why does Fraction matter?
An exact fractional answer in lowest terms, optionally as a mixed number or decimal.
How is Fraction calculated?
Addition and subtraction need a common denominator first; multiplication multiplies the numerators and the denominators directly; division multiplies by the reciprocal (flip the second fraction); the result is then simplified by dividing top and bottom by their greatest common divisor.
What are common fraction mistakes?
Adding numerators and denominators straight across (1/2 + 1/3 is not 2/5).
When should you use the Fraction Calculator?
Recipes and measurements, schoolwork, woodworking and any exact ratio arithmetic.

What is the Fraction Calculator?

A fraction calculator adds, subtracts, multiplies and divides fractions and reduces the answer to its simplest form.

How the Fraction Calculator works

Addition and subtraction need a common denominator first; multiplication multiplies the numerators and the denominators directly; division multiplies by the reciprocal (flip the second fraction); the result is then simplified by dividing top and bottom by their greatest common divisor.

Common fractions — decimal and percentage equivalents

1/20.550%
1/30.333333.33%
2/30.666766.67%
1/40.2525%
3/40.7575%
1/50.220%
1/80.12512.5%
3/80.37537.5%
5/80.62562.5%
1/100.110%
1/160.06256.25%

Worked example

1/2 + 1/3 -> 3/6 + 2/6 = 5/6

Common mistakes to avoid

  • Adding numerators and denominators straight across (1/2 + 1/3 is not 2/5).
  • Forgetting to simplify the final fraction.
  • Dividing without flipping the second fraction.
  • Mishandling mixed numbers — convert to improper fractions first.

Keywords: fraction, math.

Sources: Khan Academy — Fractions

Reviewed by the Free Tools Galaxy editorial team · Updated June 2026 · Calculated privately in your browser.

Frequently asked questions

Is the Fraction Calculator free to use?+

Yes. Every tool on Free Tools Galaxy is 100% free, runs in your browser and requires no signup.

How accurate is the Fraction Calculator?+

Fraction Calculator uses the standard fraction formula in double-precision arithmetic, so the same inputs always produce the same result and you can verify any figure by hand. It is an educational estimate — real-world outcomes depend on your actual rates, rules and assumptions.

Do you store my inputs?+

No. The Fraction Calculator runs entirely in your browser. Nothing is uploaded or saved to a server.

Can I use the Fraction Calculator on mobile?+

Yes — the interface is fully responsive and works on phones, tablets and desktops.

What are common mistakes to avoid?+

The most frequent mistake is mixing units. Double-check your inputs use a single, consistent unit before clicking Calculate.

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Likely next step

📏Significant Figures CalculatorTop match🎯Percent Error CalculatorMeasure how far a measured value is from the true value, as a percentage.🔬Scientific Notation ConverterConvert numbers between standard decimal form and scientific (and E) notation.🧪Scientific CalculatorEvaluate expressions with sin, cos, log, ln, sqrt, π and e.➕Simple CalculatorBasic arithmetic for two numbers: add, subtract, multiply, divide.📈Quadratic Equation SolverSolve ax² + bx + c = 0 with the quadratic formula and discriminant.

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Title: I built/used this free fraction calculator — instant, no signup

Body: Add, subtract, multiply and divide fractions with auto-simplification. Try it: https://freetoolsgalaxy.com/tools/fraction-calculator
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Fraction Calculator on Free Tools Galaxy — Add, subtract, multiply and divide fractions with auto-simplification. https://freetoolsgalaxy.com/tools/fraction-calculator
Medium intro
# Fraction Calculator — the free tool I keep coming back to

Add, subtract, multiply and divide fractions with auto-simplification.

Try it: https://freetoolsgalaxy.com/tools/fraction-calculator
Quora answer
The fastest way is to use a free in-browser fraction calculator: https://freetoolsgalaxy.com/tools/fraction-calculator. Add, subtract, multiply and divide fractions with auto-simplification.

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<iframe src="https://freetoolsgalaxy.com/tools/fraction-calculator?embed=1" title="Fraction Calculator" loading="lazy"
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<p><a href="https://freetoolsgalaxy.com/tools/fraction-calculator" target="_blank" rel="noopener">Powered by Fraction Calculator on Free Tools Galaxy</a></p>
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[Fraction Calculator — free online tool](https://freetoolsgalaxy.com/tools/fraction-calculator)

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Title
I built a free fraction calculator that works instantly in the browser — no signup, no ads in your face
Body
Hey r/[subreddit],

I kept needing a quick fraction calculator and most options online were slow or behind paywalls, so I built one that:

• Runs 100% in your browser (your data never leaves your device)
• No signup, no email wall, no popups
• Loads in under a second on mobile

It covers the standard fraction use cases (fraction, math) and links out to the formula + worked examples if you want to learn the math.

Link: https://freetoolsgalaxy.com/tools/fraction-calculator

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