Quick Percentage Calculator
Use this free procenten calculator to solve the three most common percentage questions in seconds.
1) What is X% of Y?
2) X is what % of Y?
3) Increase or decrease by X%
Tip: You can type decimals with a comma or dot (for example: 12,5 or 12.5).
Why a procenten calculator is so useful
Percentages appear everywhere: discounts in stores, tax rates on invoices, salary increases, investment returns, exam scores, and monthly budget reviews. A procenten calculator helps you avoid mistakes and saves time, especially when you need quick and reliable numbers.
Instead of doing every calculation manually, you can instantly answer practical questions like:
- How much is 18% of 250?
- 70 is what percent of 200?
- What is the new amount after a 12% increase?
- How much do I pay after a 25% discount?
The 3 core percentage calculations
1) Calculate a percentage of a number
Formula: (percentage ÷ 100) × number
Example: 15% of 240 = (15 ÷ 100) × 240 = 36.
2) Calculate what percentage one number is of another
Formula: (part ÷ whole) × 100
Example: 36 is what percent of 120 = (36 ÷ 120) × 100 = 30%.
3) Increase or decrease by a percentage
Increase formula: original × (1 + percentage ÷ 100)
Decrease formula: original × (1 - percentage ÷ 100)
Example: Decrease 89.99 by 21% gives 71.09 (rounded to two decimals).
Everyday scenarios where this tool helps
Shopping and discounts
If a jacket costs 120 and the sale says 25% off, the discount is 30 and the new price is 90. With this calculator, you can verify deals quickly while shopping online or in-store.
VAT, tax, and invoices
Need to add 21% VAT to a base amount or remove VAT from a total invoice? Percentage calculations make it easy to keep business documents accurate and transparent.
Salary and income changes
A 4.5% raise on a monthly salary can be calculated in seconds. You can also compare old and new salaries to see what the exact percentage difference is.
Savings and investments
Whether your portfolio gained 7% this year or your savings account yields 2.3%, percentages help you understand progress and make better financial decisions.
Common percentage mistakes to avoid
- Confusing percentage points and percent change: going from 10% to 12% is +2 percentage points, not +2%.
- Using the wrong base value: always check which number represents the whole.
- Forgetting that increase and decrease are not symmetric: -20% followed by +20% does not return to the original amount.
- Rounding too early: keep extra decimals during intermediate steps, then round at the end.
Quick mental math shortcuts
- 10% is easy: move the decimal one place left.
- 5% is half of 10%.
- 1% is 10% divided by 10.
- 15% = 10% + 5%.
- 25% is one quarter of the number.
- 50% is half of the number.
FAQ
Can I use commas for decimal numbers?
Yes. This calculator accepts both comma and dot decimal formats.
Does this calculator work for negative values?
Yes. You can enter negative numbers if needed for analysis or accounting scenarios.
Why do some results show small decimal differences?
That is normal due to rounding. Financial calculations are usually presented with two decimals, while internal math may use more precision.
Final thoughts
A reliable procenten calculator is one of the most practical tools for daily life, school, and business. Use the calculator above whenever you need to find percentages, compare values, or apply percentage increases and decreases quickly and accurately.