Percentage Increase Calculator
This percentage increase calculator takes two numbers (a starting value and a new value) and tells you exactly how much things have gone up, expressed as a percentage. Whether you are checking a salary offer, tracking a price rise, or measuring business growth, the calculator shows the result and the working behind it. If the new value turns out to be lower than the original, the calculator will point you to the right tool instead.
The number you are starting from
The number after the increase
Percentage increase
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Formula
How to use this calculator
Formula
Percentage increase:
% increase = ((New value − Original value) ÷ Original value) × 100
Worked examples
Example 1: Salary
Original: £32,000 → New: £36,500
(36,500 − 32,000) ÷ 32,000 × 100 = 14.06%
Example 2: Petrol price
Original: 142p per litre → New: 161p
(161 − 142) ÷ 142 × 100 = 13.38%
Example 3: Website traffic
Original: 1,200 visitors → New: 1,850
(1,850 − 1,200) ÷ 1,200 × 100 = 54.17%
How it works
The idea behind a percentage increase is straightforward: you want to know how much a value has grown, expressed as a share of what it started at. A rise of £5 means very different things depending on whether it started at £10 or £500.
A percentage increase tells you how much bigger the new value is relative to the original. A 10% increase means the new value is 110% of what you started with: the original 100%, plus 10% on top.
There is a quirk worth knowing. Say a value increases by 50%: it is now at 150% of its original size. To fall back to 100%, it only needs to drop by 33.3% of its current value, not 50%. The bigger the rise, the wider this gap becomes. This matters when comparing gains and losses in investments, prices, or business metrics.
Common uses
- Checking whether a salary offer is a meaningful rise or a modest one
- Comparing savings account interest from one year to the next
- Tracking how much a property has gone up in value
- Reporting revenue growth to stakeholders or in a business plan
- Calculating how much prices have risen since last year
- Measuring subscriber or follower growth on a social media account
- Seeing how much an energy bill has increased since the previous year
- Working out the real-terms increase after inflation is factored in
- Tracking a running distance or weight-training personal best over time
- Presenting year-on-year traffic growth in a clear, shareable format
Frequently asked questions
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Subtract the original value from the new value to find the amount of the increase. Divide that figure by the original value. Multiply the result by 100. The number you get is the percentage increase. For example: a rise from 80 to 100 gives (100 − 80) ÷ 80 × 100 = 25%.
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The formula is: ((New value − Original value) ÷ Original value) × 100. The original value always sits at the bottom of the division: it is the baseline the whole calculation runs from. Getting this the wrong way round is the most common mistake, and it will give you a different number.
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Yes, exactly. A 100% increase means the value has risen by an amount equal to itself, so the new total is twice the original. A value of 50 that increases by 100% becomes 100. A value that increases by 200% becomes three times the original, not twice.
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Percentage increase only applies when a value has gone up. Percentage change covers both directions: a positive result is an increase, a negative result is a decrease. If you use this calculator and the new value is lower than the original, the calculator redirects you to the percentage decrease calculator to keep the language clear.
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It needs to fall by 16.67%, not 20%. After a 20% increase, the value is at 120% of where it started. To get back to 100%, you need to lose 20 out of 120, which is 20 ÷ 120 × 100 = 16.67%. The percentage required to undo a rise is always smaller than the original rise, because you are now dividing by a larger number.
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Last reviewed: May 2026