Percentage conversion calculators
These calculators handle every type of percentage conversion needed in maths, science, business and everyday life. Whether you are converting a fraction to a percentage for a GCSE question, turning a decimal into a percentage for a spreadsheet, or working out what a ratio looks like as a percentage share, every conversion is shown with full workings so you can follow and learn the method as well as get the answer.
Percentage to Decimal Calculator
Convert any percentage to its decimal equivalent instantly, with the step shown.
Decimal to Percentage Calculator
Convert any decimal number to a percentage instantly.
Fraction to Percentage Calculator
Convert any fraction to a percentage with full step-by-step workings.
Percentage to Fraction Calculator
Convert any percentage to a simplified fraction instantly.
Ratio to Percentage Calculator
Convert any ratio to a percentage, showing each part as a share of the whole.
When you need to convert percentages
Converting exam marks to percentages
A mark of 43 out of 60 is the fraction 43/60. Dividing 43 by 60 gives 0.7167, and multiplying by 100 gives 71.67%. This is the standard percentage calculation for exam scores, and the fraction to percentage calculator handles it in one step. Many mark schemes also ask students to express one mark as a percentage of another, which is the same operation.
Reading nutritional information
UK food packaging shows nutritional values per 100g and often as a percentage of the Reference Intake (RI). If a cereal contains 8.4g of sugar per 30g serving, the sugar content as a percentage of that serving is 28%. Reference Intake percentages on packaging are pre-calculated, but knowing how to convert amounts to percentages helps you compare products accurately and understand what the figures mean.
Converting survey results for reports
If 27 out of 45 survey respondents agreed with a statement, expressing this as a fraction (27/45) is less immediately readable than converting to a percentage (60%). For a business studies coursework report, A-Level essay or university dissertation, presenting data as percentages makes comparisons across groups much clearer. If one group of 45 gave 27 agreements and another group of 60 gave 33 agreements, the fraction comparison is harder to read than 60% vs 55%.
Understanding probability as a percentage
Probability is expressed as a decimal between 0 and 1 (for example, 0.35) or as a fraction (7/20). Converting to a percentage (35%) makes the likelihood easier to communicate and understand. A weather forecast saying there is a 0.7 probability of rain is less intuitive than saying there is a 70% chance of rain. The decimal to percentage calculator converts probability values instantly.
The relationship between percentages, decimals and fractions
Percentages, decimals and fractions are three different ways of expressing the same thing: a part of a whole. A percentage tells you how many parts in every 100. A decimal is the same value expressed in base 10 notation. A fraction expresses the part directly over the whole. They are all equivalent and interchangeable.
Percentages are most useful for communication: saying that 40% of customers preferred a product is clearer than 0.4 or 2/5. Decimals are most useful for calculation: multiplying £250 by 0.4 is easier than multiplying by 40% or 2/5 in a spreadsheet. Fractions are most useful in exact maths: 1/3 is more precise than 33.3%, which is a rounded approximation. Knowing when to use each form is a key skill covered in the GCSE percentages revision guide.
The common conversions below are worth learning by heart. Once you know that 25% is 0.25 and 1/4, many mental maths calculations become much faster. For practice with all three forms together, the fractions, decimals and percentages worksheet covers all conversion types with answers.
| Percentage | Decimal | Fraction |
|---|---|---|
| 50% | 0.5 | 1/2 |
| 25% | 0.25 | 1/4 |
| 10% | 0.1 | 1/10 |
| 75% | 0.75 | 3/4 |
| 33.3% | 0.333 | 1/3 |
| 20% | 0.2 | 1/5 |
Related resources
Fraction to Percentage Worksheet
Convert fractions to percentages with 20 practice questions and answers.
Percentage to Decimal Worksheet
Convert percentages to decimals with practice questions and worked answers.
KS3 Percentages
KS3 guide covering percentage conversions, increase, decrease and change.
Percentage Formula Sheet
All key percentage formulas on one printable revision page.