Quick answer: Percentages, fractions and decimals express the same proportion in different forms. Converting between them makes formulas easier to understand and check.
Try it: Open the free BuzBolt Percentage Calculator. No signup is required.
Understand the method
To convert percentage to decimal, divide by 100. To convert decimal to percentage, multiply by 100. To write a percentage as a fraction, put it over 100 and simplify when possible.
The representation can change without changing the quantity. Choose decimals for multiplication, percentages for communication and fractions when an exact ratio is useful.
Worked example
25% = 0.25 = 1/4; 12.5% = 0.125 = 1/8; 150% = 1.5 = 3/2.
What people often get wrong
Do not read 0.5 as 0.5%: 0.5 in decimal notation is 50%.
A practical way to use this
Use familiar benchmarks—10%, 25%, 50%—to sanity-check unusual results.
Frequently asked question
Is 100% always equal to 1? Yes, as a multiplier or whole proportion.
Move among percent, decimal and fraction
25% equals 0.25 and also 1/4. Convert a percentage to a decimal by dividing by 100; convert a decimal to a percentage by multiplying by 100. To write a fraction, express the value over 100 and simplify when possible.
Apply it to your own task
For example, 12.5% = 0.125 = 1/8. These forms have the same value but are more convenient in different contexts: percentages for communication, decimals for multiplication and fractions for exact comparisons.
Related reading
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