Percentage Calculator
Compute percent change, profit/loss percentage, discount price, x% of y, and percent increase/decrease.
Input Data
Results
At a glance:A percentage is a ratio per hundred. This tool covers: x% of y = y·x/100; x as a percent of y = x/y×100%; the base that x is y% of = x/(y/100); change = x·(1±y/100). Percent change = (new−old)/old×100%. Profit/loss % = (sell−cost)/cost×100%. Discount price = price·(1−rate).
Formula
x% of y = y × x / 100.
x as % of y = x / y × 100%.
percent change = (new − old)/old × 100%.
profit/loss % = (sell − cost)/cost × 100%.
discount price = price × (1 − rate).
$$\text{percent}=\frac{x}{y}\times 100\%$$$$\Delta\%=\frac{\text{new}-\text{old}}{\text{old}}\times 100\%$$$$\text{profit}\%=\frac{\text{SP}-\text{CP}}{\text{CP}}\times 100\%$$How to Use
- Pick a mode.
- Enter x and y per the mode (e.g. change: x=old, y=new).
- Read the result and note.
Quick discount table (base 100)
| Discount | Price | Save |
|---|---|---|
| 10% | 90 | 10 |
| 20% | 80 | 20 |
| 25% | 75 | 25 |
| 50% | 50 | 50 |
Discounted price = price × (1 − rate).
Case Studies
Percent change 80 → 100
(100−80)/80×100% = 25% increase.
Profit: cost 80, sell 100
Profit = 20; profit% = 20/80×100% = 25%.
Discount: price 200, 20% off
Discounted = 200×0.8 = 160; save 40.
FAQ
Percent vs percentage point?
Percent is a ratio; a percentage point is the difference of two percentages (20%→25% is +5 points).
What if profit% is negative?
A selling price below cost gives a negative value, i.e. a loss percentage.
20% off = which 'fold'?
You pay 80% of the price, i.e. '20% off' means 8折 in the local phrasing.
Related Tools
References
Content review: Calculatorism Science Team. Percentage, change, profit/loss and discount formulas have been verified. Results are for reference only.