Percentage Calculator
Calculate percentages, increases and differences
How to use Percentage Calculator
Calculate percentages, percentage increases, decreases and differences easily. Multiple calculation modes. Free online tool.
What are percentages used for in everyday life?
Percentages express a proportion relative to 100. They appear in almost every quantitative context — from shopping and finance to statistics and health.
- Discounts and sales: A 30% discount on a €120 item saves €36. Calculate the final price before committing to a purchase.
- Tax calculations: Add VAT or sales tax to a net price, or calculate the tax component from a gross price.
- Tip calculation: A 15% tip on a €45 dinner is €6.75. Use this to calculate fairly without mental arithmetic.
- Statistics and data: "Sales increased by 23% year-over-year" — calculate absolute values from percentage changes or vice versa.
- Grades and scores: Convert raw scores to percentages, or calculate what score is needed to achieve a target average.
- Finance: Interest rates, portfolio returns, inflation figures — all expressed as percentages requiring precise calculation.
Common calculations: (1) X% of Y = Y × X/100. (2) X is what % of Y = (X/Y) × 100. (3) Percentage change = ((new − old) / old) × 100.
Frequently Asked Questions
What is the percentage change formula?
Percentage change = ((New Value − Old Value) / Old Value) × 100. A positive result means an increase; negative means a decrease. Example: sales rose from 80 to 100 units — change = ((100−80)/80)×100 = 25% increase.
What is the difference between percentage points and percent?
Percentage points measure the arithmetic difference between two percentages. If interest rates rise from 2% to 5%, that is a 3 percentage point increase, but a 150% relative increase. Confusing these two is a common error in financial reporting.
How do I reverse a percentage to find the original value?
If a price including 21% VAT is €121, the original net price is €121 / 1.21 = €100. More generally: original = final / (1 + percentage/100). This is the reverse percentage calculation.
What is a basis point?
A basis point (bp) is 0.01% — one hundredth of a percentage point. Used in finance where small differences matter: a 25 basis point interest rate change means 0.25%. Central banks often raise or lower rates in 25 or 50 basis point increments.
How do I calculate compound percentage growth?
For growth over multiple periods: final = initial × (1 + rate)^periods. For example, €1,000 growing at 5% annually for 10 years = 1000 × 1.05^10 = €1,629. Use the Compound Interest Calculator for this type of calculation.
Percentage calculator vs fraction calculator vs ratio calculator
Percentages express proportion per hundred — the most common format for everyday communication. Fractions express exact ratios (3/4) — more precise for mathematics. Ratios compare two quantities directly (3:4) — common in recipes and scale maps. Decimals are percentages divided by 100 (75% = 0.75). All four represent the same underlying concept — proportion — in different notations suited to different contexts.