How to Calculate a Percentage: The Complete Guide
The four core formulas — finding X% of Y, working out what percentage one number is of another, adding and subtracting percentages — with worked examples and mental shortcuts.
Read guide → ConceptsPercentage Change vs Percentage Difference: What's the Difference?
These two calculations use different denominators and answer different questions. Understanding which to use — and when — prevents a very common error in analysis and reporting.
Read guide → Tax & FinanceHow to Add VAT (and Remove It): A Plain English Guide
How to add 20% VAT to a price, how to correctly remove VAT from a VAT-inclusive figure, and why simply subtracting 20% gives the wrong answer.
Read guide → ShoppingHow to Calculate a Discount Percentage
Calculate any sale price, find the discount percentage from a was/now price, handle stacked discounts and work out what an item cost before the markdown.
Read guide → SalaryHow to Calculate a Pay Rise (and Check If It Beats Inflation)
Work out your pay rise as a percentage, convert a percentage offer into a new salary, and check whether your raise actually increases your purchasing power in real terms.
Read guide → FundamentalsPercentage Increase and Decrease: Step-by-Step Guide
The formula, the most common mistake (wrong denominator), why increases and decreases don't cancel out, and how to find the original value from a known result.
Read guide → ConceptsWhat Is a Reverse Percentage? (And How to Calculate One)
Reverse percentages work backwards from a result to find the original value. Find pre-VAT prices, pre-discount prices and original amounts before any percentage was applied.
Read guide → ConceptsPercentage Points vs Percent: Why Everyone Gets This Wrong
A rise from 4% to 6% is 2 percentage points — but it's a 50% relative increase. These two measures describe the same move very differently, and the distinction matters.
Read guide → EducationHow to Calculate Your Test Score as a Percentage
Convert marks to a percentage, correctly combine scores from multiple sections, and calculate the minimum marks needed to hit a target grade.
Read guide → Tips & Tricks5 Percentage Tricks You Can Do in Your Head
Mental arithmetic shortcuts that cover most percentage situations — tips, discounts, quick estimates — without reaching for a calculator. Includes the commutative property trick most people don't know.
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