Fraction Calculator
Add, subtract, multiply, and divide fractions and mixed numbers. Get simplified results in lowest terms, mixed number form, and decimal — with a step-by-step breakdown of the math. Free, private, and runs entirely in your browser.
What does this fraction calculator do?
This free online fraction calculator performs all four basic arithmetic operations on fractions and mixed numbers: addition, subtraction, multiplication, and division. It returns the result in three forms at once — simplified fraction, mixed number, and decimal — along with a step-by-step breakdown that shows exactly how the answer was derived.
Fractions show up everywhere: recipes, measurements, financial ratios, probability, and of course math homework. But doing fraction arithmetic by hand is error-prone. Getting a common denominator, remembering to flip the second fraction when dividing, simplifying at the end — one small mistake and the whole answer is wrong. This calculator handles all of that automatically, so you can focus on the problem rather than the mechanics.
The tool supports proper fractions (like 3/4), improper fractions (like 7/3), mixed numbers (like 2 1/3), and whole numbers (like 5, which is just 5/1). Negative values are also supported. Everything runs locally in your browser — no data is sent to a server.
How to use the fraction calculator
- Enter the first fraction: Type the numerator and denominator. If it's a mixed number, also enter the whole number part (e.g. for 2 1/3, enter 2 in "Whole", 1 in "Numerator", and 3 in "Denominator").
- Choose the operation: Select add (+), subtract (−), multiply (×), or divide (÷).
- Enter the second fraction: Same as the first — numerator, denominator, and an optional whole number.
- Click Calculate: The result appears instantly in three forms, along with a step-by-step breakdown.
- Switch to Simplify mode: To simplify a single fraction or convert between fractions and decimals, use the second tab.
Why use this fraction calculator?
All four operations
Add, subtract, multiply, and divide fractions and mixed numbers. The calculator handles the sign and reduces the result automatically.
Three result formats
Every answer is shown as a simplified fraction, a mixed number, and a decimal — so you can use whichever form fits your context.
Step-by-step breakdown
See exactly how the answer was calculated, including finding the LCD, converting to improper fractions, and simplifying with the GCD.
Mixed numbers supported
Enter whole numbers alongside fractions. The calculator converts mixed numbers to improper fractions internally and converts back at the end.
100% private
Everything runs in your browser. No numbers are sent to a server. Close the tab and the data is gone.
Works offline
Once the page loads, the calculator keeps working without an internet connection. Perfect for flights or remote areas.
Fraction formulas explained
Here are the standard formulas for the four basic operations on fractions. These are the formulas this calculator uses under the hood.
After adding, simplify by dividing the numerator and denominator by their GCD.
The same denominator rule applies: find a common denominator, subtract the numerators, then simplify.
Multiply the numerators together and the denominators together, then simplify.
Multiply the first fraction by the reciprocal of the second (flip the second fraction), then simplify.
Example: 12/18 → GCD(12, 18) = 6 → 12÷6 / 18÷6 = 2/3
Fraction operations at a glance
| Operation | What to do with denominators | What to do with numerators | Example |
|---|---|---|---|
| Addition | Find a common denominator (LCD) | Add the numerators | 1/2 + 1/3 = 5/6 |
| Subtraction | Find a common denominator (LCD) | Subtract the numerators | 3/4 − 1/3 = 5/12 |
| Multiplication | Multiply the denominators | Multiply the numerators | 2/3 × 3/5 = 6/15 = 2/5 |
| Division | Multiply by the reciprocal | Multiply the numerators | 3/5 ÷ 1/2 = 6/5 |
Who uses a fraction calculator?
Students and teachers
- Check homework answers for fraction arithmetic
- Learn step-by-step methods for finding LCD and simplifying with GCD
- Prepare lesson materials and practice problems
Cooking and baking
- Scale recipes up or down (e.g. halving 3/4 cup to 3/8 cup)
- Combine measurements from multiple sources
- Convert between cups, tablespoons, and teaspoons when recipes use fractions
Construction and carpentry
- Add and subtract measurements in inches and fractions of inches
- Divide materials into equal parts (e.g. splitting a board into thirds)
- Convert between fractional and decimal inches
Finance and business
- Calculate ratios and proportions expressed as fractions
- Work with interest rates and percentages expressed as fractions
- Split invoices or quantities proportionally
Science and engineering
- Combine measured values with different units that are expressed as fractions
- Work with probabilities and odds
- Perform dimensional analysis involving fractional exponents and ratios
Common fraction mistakes to avoid
- Adding denominators directly. When adding 1/2 + 1/3, you do not add the denominators (2 + 3 = 5). You find a common denominator first: 3/6 + 2/6 = 5/6.
- Forgetting to flip when dividing. Dividing by a fraction is the same as multiplying by its reciprocal. So 3/5 ÷ 1/2 = 3/5 × 2/1 = 6/5.
- Not simplifying the final answer. A result of 6/15 should be simplified to 2/5 by dividing both parts by their GCD (3).
- Mixing up the numerator and denominator. The numerator is the top number (how many parts you have), and the denominator is the bottom number (how many parts the whole is divided into).
- Ignoring signs. A negative fraction can have the minus sign on the numerator, the denominator, or in front of the whole fraction — they all mean the same thing. The calculator handles signs correctly.