Choose the question that matches your task
Find a percentage of a value, calculate a rate, compare two values, apply a change, or work backward.
FREE ONLINE PERCENTAGE CALCULATOR
Percentage Calculator
Solve everyday percentage questions, calculate percent change or difference, apply an increase or decrease, and work backward to the original value.
Instant resultsNo sign-upRuns in your browser
BASIC PERCENTAGE
What is X% of Y?
Enter a percentage and a value to calculate the corresponding part.
result = value × percentage ÷ 100FIND THE RATE
X is what percent of Y?
Use this for scores, ratios, completion rates, shares, and other part-to-whole comparisons.
percentage = part ÷ whole × 100COMPARE TWO VALUES
Percentage change and percentage difference
Change uses the old value as the reference. Difference treats both values symmetrically.
change = (new − old) ÷ old × 100difference = |a − b| ÷ average(|a|, |b|) × 100APPLY A PERCENTAGE
Increase or decrease a value by a percent
Useful for discounts, markups, tips, budget changes, and quick “plus/minus X%” calculations.
WORK BACKWARD
Find the original value before a percentage change
Enter the final value and the percentage that was previously added or removed.
original = final ÷ (1 ± percentage ÷ 100)HOW TO USE
How to Use Motricialy Percentage Calculator
Enter the numbers you already know
Decimals and negative values are supported where the formula has a meaningful result.
Read the result and formula context
Results update instantly, with supporting change/difference or amount information when useful.
KEY FEATURES
Key Features of Motricialy Percentage Calculator
Five common percentage workflows
Handle percent-of, find-the-rate, change/difference, adjustment, and reverse-percentage questions.
Change and difference side by side
See why a before/after change is not the same as a symmetric percentage difference.
Reverse percentage
Recover the original price or value when you know the final result and prior increase or decrease.
Instant reactive results
No Calculate button is required; outputs refresh whenever an input changes.
Readable precision
Results keep useful decimal precision without flooding the interface with insignificant trailing zeros.
Browser-only processing
No account, server calculation, or uploaded calculator data is required.
PERCENTAGE GUIDE
Choose the denominator before you calculate
Most percentage mistakes come from using the wrong reference value. “30 is what percent of 120?” uses 120 as the whole, while “from 80 to 100” uses 80 as the starting reference for percent change.
Percent ofPart from a rate
Multiply the whole by the percentage expressed as a decimal.
Percent changeOld value is the base
Divide the signed change by the starting value.
Percent differenceNo start value
Compare the absolute gap against the average magnitude of both values.
If you need to continue the calculation in a table, Motricialy's Online Excel Editor and Online CSV Editor can work with the resulting values directly in your browser.
FAQ
Percentage Calculator questions
How do I calculate 20% of 150?
Convert 20% to 0.20 and multiply by 150. The result is 30.
How do I find what percent one number is of another?
Divide the part by the whole and multiply by 100. For example, 45 ÷ 180 × 100 = 25%.
What is the difference between percent change and percent difference?
Percent change has a defined starting value, so the old value is the denominator. Percentage difference is symmetric: neither value is treated as the starting point, so the average magnitude is used as the reference.
Why is a 25% increase not reversed by a 25% decrease?
The second percentage is applied to a different base. Increasing 80 by 25% gives 100, while decreasing 100 by 25% gives 75. Returning from 100 to 80 requires a 20% decrease.
Can the calculator find the original value before a discount?
Yes. Reverse % mode divides the final value by one minus the discount rate. For example, $85 after a 15% discount corresponds to an original value of $100.
Does this Percentage Calculator upload my numbers?
No. The formulas run locally in your browser, and the tool does not need to send your calculator inputs to a server.