Divide the Top Number by the Bottom Number
A fraction like a/b is really a division problem in disguise. Divide the numerator (a) by the denominator (b) and out comes the decimal:
1/3 → 1 ÷ 3 = 0.3333… (repeating)
Not every fraction divides evenly. 1/3 keeps going as 0.333... forever, so instead of writing endless digits, mathematicians mark the repeating part with a bar: 1/3 = 0.3̄
Turning That Decimal Into a Percent
Once you have the decimal, a percentage is just one more move away - multiply by 100.
1/8 = 0.125 = 12.5%
Common Fraction, Decimal, and Percent Values
| Fraction | Decimal | Percent |
|---|---|---|
| 1/2 | 0.5 | 50% |
| 1/3 | 0.333… | 33.33% |
| 2/3 | 0.666… | 66.67% |
| 1/4 | 0.25 | 25% |
| 3/4 | 0.75 | 75% |
| 1/5 | 0.2 | 20% |
| 2/5 | 0.4 | 40% |
| 3/5 | 0.6 | 60% |
| 4/5 | 0.8 | 80% |
| 1/8 | 0.125 | 12.5% |
| 3/8 | 0.375 | 37.5% |
| 5/8 | 0.625 | 62.5% |
| 7/8 | 0.875 | 87.5% |
| 1/10 | 0.1 | 10% |
| 1/100 | 0.01 | 1% |
The halves, quarters, and eighths are worth knowing by heart. They turn up in recipes, sale prices, and everyday measurements constantly, and memorizing them beats reaching for a calculator every single time.
Reversing the Process: Decimal Back to Fraction
Want to go the other way? Here's how a decimal turns back into a fraction:
- Place the decimal over 1, as if it were already a fraction: 0.75/1
- For each digit after the decimal point, multiply top and bottom by 10: 75/100
- Simplify by dividing both numbers by their greatest common factor: 75/100 = 3/4
What About Mixed Numbers?
A mixed number such as 2½ looks trickier than it is - handle the whole number and the fraction on their own, then add them: 2½ = 2 + 0.5 = 2.5
An improper fraction like 7/4 converts the same way any fraction does: just divide. 7 ÷ 4 = 1.75, or written as a mixed number, 1¾. If you want to double check a conversion like this by hand, SolverCalc's calc solver tools handle the division instantly.