Percentage Calculator
X% of Y, share as a percent, and percent change-with formulas, examples, and FAQ in your browser.
Everyday Examples
🛒 Shopping sale
Jacket €80, 20% off → save €16, pay €64.
🧾 VAT / sales tax
€100 + 23% VAT → €23 tax, total €123.
📈 Salary raise
€3,000/mo + 5% → +€150, new €3,150.
🏦 Bank interest
€10,000 at 4%/yr → €400 interest (simple).
☕ Price increase
€2.50 → €2.80 → ≈12% vs old price.
📊 Exam score
42 / 56 right → 75%.
How to Calculate Percentages
Quick context, then worked tables aligned with the calculator tabs.
When should you use this?
🧾 Checkout & invoices
Find a discount or tax slice of a total.
💼 Pay & grades
Turn part vs whole into a percent.
📈 Trends
Old vs new price or KPI - change vs the starting value.
Common mistakes
⚠️ Points vs change
Mixing percentage points (e.g. 20% → 25% = 5 points) with relative % change.
🧮 Discount & tax
Wrong order of discount and tax.
🔢 Wrong whole
In X vs Y, name your denominator before calculating.
What is X% of Y? (parts of a whole)
Discounts, tips, tax: you know the rate - multiply total × (percent ÷ 100).
| Question | Calculation | Answer | Real-world context |
|---|---|---|---|
| What is 10% of 50? | 50 × 0.10 | 5 | Ten percent deposit on a 50 unit bill |
| What is 25% of 200? | 200 × 0.25 | 50 | Quarter of a 200 unit project budget |
| What is 8% of 1200? | 1200 × 0.08 | 96 | Rough VAT-style chunk on a 1200 total |
| What is 15% of 84? | 84 × 0.15 | 12.6 | Restaurant tip line on an 84 check |
| What is 3% of 9500? | 9500 × 0.03 | 285 | Small percent fee on a large transfer |
X is what % of Y? (share or completion)
Part ÷ whole × 100 - scores, progress, share of a total.
| Question | Calculation | Answer | Real-world context |
|---|---|---|---|
| 30 is what % of 150? | (30 ÷ 150) × 100 | 20% | One line item versus whole invoice |
| 7 is what % of 28? | (7 ÷ 28) × 100 | 25% | Weekly workouts completed of a 28-day plan |
| 45 is what % of 90? | (45 ÷ 90) × 100 | 50% | Half the questions correct on a quiz |
| 120 is what % of 400? | (120 ÷ 400) × 100 | 30% | Conversion rate from 400 visitors |
| 18 is what % of 144? | (18 ÷ 144) × 100 | 12.5% | Slice of a 144 hour month on one task |
Percentage change between two values
(new - old) ÷ |old| × 100 - always vs the starting value.
| Question | Calculation | Answer | Real-world context |
|---|---|---|---|
| From 80 to 100 | ((100 - 80) ÷ 80) × 100 | +25% | Revenue lift from a campaign baseline |
| From 200 to 150 | ((150 - 200) ÷ 200) × 100 | -25% | Stock pullback from a recent peak |
| From 40 to 40 | ((40 - 40) ÷ 40) × 100 | 0% | Flat month-over-month metric |
| From 50 to 65 | ((65 - 50) ÷ 50) × 100 | +30% | Support tickets resolved vs prior sprint |
| From 250 to 235 | ((235 - 250) ÷ 250) × 100 | -6% | Utility bill seasonally lower |
Key Percentage Terms
Percentage increase
The relative growth from an original amount expressed in hundredths of that starting value. If sales climb from €1,000 to €1,200, the increase is 20% because the €200 gain is one-fifth of the baseline you measured against.
Profit margin
Profit as a share of revenue, not of cost. A 30% margin means thirty cents of each revenue euro remains after direct expenses. Do not confuse it with markup, which divides by cost instead of price.
Reverse percentage
Working backward from a post-change value to the original whole. If €123 includes 23% tax, the net portion is not 77% of 123 unless the policy says so - define whether the rate applies to net or gross before you invert the operation.
Basis point (finance)
One hundredth of a percentage point. Analysts say 25 bps instead of 0.25 percentage points when discussing bond yields or central bank moves so the increment stays unambiguous on noisy trading floors.
Frequently Asked Questions
Common questions about the percentage calculator.
What is the difference between percentage points and a percent increase?
Percentage points describe the gap between two rates that are already expressed as percents. If a tax rate rises from 20% to 25%, that is five percentage points higher. A percent increase compares the change to the original value: that same jump is a 25% increase relative to 20%. News headlines often mix the two, so always check which base the writer used.
What does 100% mean in practice?
One hundred percent means the entire reference amount you chose as the whole. If your paycheck is the whole, then 100% of it is the gross total before any splits. If a download bar is the whole, 100% means the file finished. The same number can represent different wholes, so always identify what counts as 100% before you interpret a result.
Can a percentage be greater than 100%?
Yes, whenever you compare a part to a smaller whole or describe growth relative to a starting value. If revenue doubles, that is a 100% increase; if it triples, that is a 200% increase. Saying you saved 120% of your goal only makes sense if the goal was defined in a way that allows overshooting - otherwise stick to plain numbers for clarity.
How do I read small percentages like 0.5% on a loan or fee?
Treat 0.5% as half of one percent, not half a percent point in isolation. On €10,000, 0.5% equals €50. For annual rates, remember that a tiny percent on a large balance or a long timeline still matters. Always pair the percentage with the amount and the period so you are not comparing unlike things.
Is this calculator financial or legal advice?
No. It is an educational tool that applies standard math to numbers you supply. Real contracts, payroll taxes, loan APRs, and court deadlines have rules, rounding, and definitions that only a qualified professional or official document can settle. Use these results to estimate and learn, then confirm anything binding with an expert or primary source.
About these results
Outputs follow the formulas shown on this page from the inputs you enter. Rounding, local tax law, compounding frequency, or institution-specific rules can change real-world totals. Treat answers as planning aids, not statements from a bank, school, or government unless you verify them against authoritative data.