All PercentNinja Calculators
The PercentNinja calculator library brings together a complete set of free online percentage tools for everyday use, business calculations, and education. Whether you need to work out a discount, calculate VAT, measure percentage change, or analyse pricing and profit, these calculators provide fast and accurate results.
Each calculator is designed for real-world scenarios. Shoppers can calculate savings and sale prices, students can check homework or learn percentage formulas, and business users can analyse margins, markups, VAT, and pricing adjustments. All tools work with any currency or numeric value and include clear explanations so you understand how the result is calculated.
Every calculator page includes worked examples, simple formulas, and frequently asked questions to help you learn as you go. Browse the tools below to find the percentage calculator that matches your task, from basic percentage conversions to advanced pricing and business calculations.
Browse our complete collection of free percentage calculators. Each tool includes a clear explanation, worked examples, and FAQs so you can understand the answer (not just get a number).
What is X% of Y?
Calculate a percentage amount for discounts, VAT/tax amounts, tips, and commissions.
X is what percent of Y?
Find what percentage one number represents of another (scores, budgets, benchmarks).
Percentage Increase / Decrease
Measure growth or decline between an old value and a new value.
Add or Subtract a Percentage
Apply a percentage change directly to a single starting value.
Percentage Difference
Compare two numbers relative to their average (useful for comparisons).
Reverse Percentage
Work backwards to the original value before a percentage change or discount.
VAT Calculator
Add VAT, remove VAT, or calculate VAT amount only (UK-friendly).
Reverse VAT Calculator
Find the net price and VAT amount from a VAT-inclusive total.
Discount Calculator
Calculate final price after a percentage discount and see savings.
Sale Price Calculator
Find the discount percent when you know original price and sale price.
Markup & Margin Calculator
Cost to selling price + profit, with markup and margin explained.
Markup Calculator
Set selling price from cost and markup percentage.
Margin Calculator
Calculate profit margin from cost and selling price.
Markup vs Margin Converter
Convert markup % to margin % (and margin to markup).
Tip Calculator
Calculate tip amount, total, and per‑person split.
Percent ↔ Decimal Converter
Convert percentages to decimals and decimals to percentages.
Average Percentage Calculator
Calculate a simple average from multiple percentage values.
Percentage Change
Calculate percent increase/decrease from an old value to a new value.
Compound Percentage Change
Calculate repeated percentage growth/decline over multiple periods.
Percentage to Fraction
Convert a percentage (including decimals) into a simplified fraction.
Fraction to Percentage
Convert a fraction to a percentage using numerator and denominator.
Decimal to Percentage
Convert a decimal to a percentage (e.g. 0.125 → 12.5%).
Exam Percentage
Convert a score into a percentage (score ÷ total × 100).
Percentage Progress
Track percent complete towards a goal and see how much remains.
Percentage of Time
Work out what percent one time period is of another.
Cost From Margin
Find cost price needed to hit a target margin at a given selling price.
Compound Interest Calculator
Estimate future value with compounding and optional monthly contributions.
Simple Interest Calculator
Work out interest earned and final amount when interest is not compounded.
Savings Calculator
Project savings growth with a starting balance and regular monthly deposits.
Loan Interest Calculator
Estimate monthly repayment, total repayment, and total interest.
APR Calculator
Estimate annual percentage rate from repayment, term, and fees.
Investment Return Calculator
Measure gain, ROI, and return multiple from start value to finish value.
Percentage Reduction Calculator
Measure how much a value has fallen from an original amount.
Percentage Remaining Calculator
Find how much remains and the percentage left from a total.
Percentage of Total Calculator
Work out what share one part represents of the whole.
Weighted Percentage Calculator
Calculate weighted averages for grades, KPIs, and scorecards.
Percent Error Calculator
Measure percent error between estimated and actual values.
Break-even Calculator
Estimate break-even units based on fixed costs and contribution per unit.
Popular percentage question pages
Get instant answers to common percentage questions and then use the main calculator for any custom percentage problem.
What is 5 % of 50
Quick answer + step-by-step explanation for this percentage question.
What is 5 % of 80
Quick answer + step-by-step explanation for this percentage question.
What is 5 % of 100
Quick answer + step-by-step explanation for this percentage question.
What is 5 % of 120
Quick answer + step-by-step explanation for this percentage question.
What is 5 % of 500
Quick answer + step-by-step explanation for this percentage question.
What is 10 % of 50
Quick answer + step-by-step explanation for this percentage question.
What is 10 % of 80
Quick answer + step-by-step explanation for this percentage question.
What is 10 % of 100
Quick answer + step-by-step explanation for this percentage question.
What is 10 % of 120
Quick answer + step-by-step explanation for this percentage question.
What is 10 % of 250
Quick answer + step-by-step explanation for this percentage question.
What is 12 % of 50
Quick answer + step-by-step explanation for this percentage question.
What is 12 % of 75
Quick answer + step-by-step explanation for this percentage question.
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Which calculator should I use?
- Percentage of: “What is 20% of £150?” → Percent of a Number
- What percent: “£45 is what % of £60?” → What Percent is X of Y?
- Change over time: “£100 to £120” → Increase/Decrease
- Apply a change: “Add 10% to £200” → Add/Subtract
- Final price after discount: “£120 minus 15%” → Discount
- Original price before discount: “£80 after 20% off” → Reverse %
- VAT totals: “Add/remove VAT from a price” → VAT