Percentage Increase Calculator
From £100 to £120 is a 20% increase. Type two values; the calculator shows the change, the formula, and the working.
The classic increase calculation: how much one value has grown over another. UK use cases below include pay rises, Land Registry house price growth, and ONS CPI year-on-year comparisons.
How it works.
Formula: ((New − Original) ÷ Original) × 100.
How to calculate percentage increase, step by step:
- Subtract the original value from the new value: New − Original.
- Divide that change by the original value.
- Multiply by 100 to express it as a percentage.
Worked example — from £100 to £120: (120 − 100) ÷ 100 = 0.20, × 100 = 20% increase. Negative results indicate a decrease — use the decrease calculator for clarity in those cases.
Worked examples
£35,000 to £36,750 = 5% — a typical UK 5% pay rise on a £35k salary (gross; the real take-home rise will be lower — see the salary increase calculator).
£250,000 to £262,500 = 5% — if your area's HPI rose 5% in a year, this is what your £250k home is worth on paper.
£1,928 to £2,028 = 5.19% — an Ofgem default cap rise of about 5% in a quarterly review.
£100 to £103.20 = 3.20% — the kind of CPI increase ONS reports as headline UK inflation in a calmer month.
£50,270 to £52,000 = 3.44% — a basic-rate tax band threshold rise (illustrative; threshold has been frozen).
4.50% to 4.75% = 5.56% — a 0.25-percentage-point Bank of England base-rate hike is a 5.56% relative rise on the rate. (See the percentage-points calculator for the absolute-vs-relative distinction.)
Council Tax Band D £2,200 to £2,310 = 5% — a typical UK council uplift at the 5% statutory referendum cap.
NS&I Premium Bond rate 4.00% to 4.40% = 10% — relative rate change when the prize fund rate moves (different to the absolute 0.40 percentage point).
Fuel duty 52.95p to 57.95p = 9.44% — the kind of rise the Treasury sometimes reverses at Budget.
State Pension £221.20/wk to £241.30/wk = 9.09% — the 2026/27 triple-lock uplift driven by autumn 2025 wage growth.
If this is a UK pay rise:
Salary Increase Calculator (with UK tax) →Pay rises don't translate 1:1 to take-home — tax bands, NI, and the £100k personal-allowance taper all reduce the real net rise. The salary-increase calculator shows what a pay rise actually adds to your bank account.
Sources:
ONS Consumer Price Indices · HM Land Registry UK House Price Index
· retrieved 2026-05-12.
Frequently asked questions
How do you calculate a percentage increase?
Subtract the original from the new value, divide by the original, multiply by 100. From £100 to £120 is (120 − 100) ÷ 100 × 100 = 20%.
How do you work out a pay rise as a percentage?
Same formula. From £35,000 to £36,750 is (36750 − 35000) ÷ 35000 × 100 = 5%. To see the take-home effect, use the salary-increase calculator on this site.
How do I increase a number by a percentage?
Multiply by (1 + percent ÷ 100). To increase 280 by 5%, multiply 280 × 1.05 = 294. To increase 740 by 25%, 740 × 1.25 = 925.
What is the percentage increase formula?
((New − Original) ÷ Original) × 100. The change as a fraction of the starting value, expressed as a percentage.
Is a percentage increase the same as a percentage point increase?
No. If a tax rate rises from 5% to 7%, that's a 2 percentage point rise (absolute) but a 40% increase (relative). The percentage points calculator on this site explains the distinction.
Why does my real take-home rise less than my pay rise?
Because UK tax bands are tiered. Some of the rise will fall in higher bands — income tax (20/40/45%), National Insurance (8/2%), and possibly student loan repayments. The salary-increase calculator shows the net figure.
How do I compare a 3% rise to inflation?
Subtract the CPI rate from your nominal rise. If you got 3% but CPI is 4%, your real income fell by about 1%. Use the inflation-impact calculator for the precise effect over time.
How do I work out a percentage increase between two months?
Same formula treating month 2 as the new value and month 1 as the original. £1,200 in March, £1,260 in April: (1260 − 1200) ÷ 1200 × 100 = 5% month-on-month rise. For year-on-year, use month-13 over month-1.
Can a percentage increase be more than 100%?
Yes. A doubling is a 100% increase; a tripling is a 200% increase. From £50 to £200 is a 300% increase: (200 − 50) ÷ 50 × 100. There's no upper limit; the percentage just keeps growing as the new value moves further above the original.
How do I find the original value from a percentage increase?
Divide the new value by (1 + percent ÷ 100). If something is now £120 and that's a 20% rise from the original: 120 ÷ 1.20 = £100. The reverse-percentage calculator on this site does this for any rise %.
What's the difference between percentage increase and percentage points?
Percentage increase is relative: a rate going from 5% to 7% is a 40% increase (((7 − 5) ÷ 5) × 100). The same change is 2 percentage points in absolute terms. UK news often confuses the two; always check which is meant when comparing tax-rate or interest-rate changes.
Why does my percentage increase look smaller than I expected?
Two common reasons. (1) You may have used the new value as the denominator instead of the original: 100 to 120 is a 20% increase from 100, but 120 to 100 is a 16.67% decrease from 120. (2) You may be confusing absolute and relative: a 0.5 percentage point rise from a 4% base is a 12.5% relative rise.