How do I calculate percentage change?

Percentage change = (new − old) ÷ old × 100. Going from 80 to 100 is (100 − 80) ÷ 80 = +25%. Going from 100 to 80 is −20%. The denominator is always the starting value.

Why is a 25% increase not undone by a 25% decrease?

Because the base changes. 100 → 125 (+25%), then 125 → 93.75 (−25%). Reversing a gain requires a smaller percentage of the larger number: undoing +25% takes exactly −20%.

What is the difference between percentage change and percentage points?

If a rate moves from 10% to 15%, that's a 5 percentage-point increase but a 50% relative increase. News and finance frequently blur these — knowing the difference prevents serious misreading.

How is percentage difference different from percentage change?

Percentage change is directional (old → new). Percentage difference compares two values symmetrically using their average as the base: |a − b| ÷ ((a + b) ÷ 2) × 100. Use change for over-time comparisons, difference for side-by-side ones.

How do I handle a change from a negative number?

Percentage change across zero or from negative bases is mathematically ambiguous and often misleading (a profit going from −$100 to +$50 is not '150%'). Report the absolute change instead in those cases.

Percentage Change Calculator — Increase & Decrease Betwe...

Remove Ads

Share on Social Media:

Percentage Change Calculator — Growth and Decline, Measured Correctly

Revenue went from $42,000 to $51,500 — up what percent? Traffic fell from 18,400 to 15,100 — down what percent? This free calculator answers instantly using the correct base (always the starting value), shows absolute change alongside, and helps you avoid the three classic percentage traps that distort reports and headlines. In-browser, no signup.

The Formula and a Worked Pair

% change = (new − old) ÷ old × 100

$42,000 → $51,500: (9,500 ÷ 42,000) × 100 = +22.6%
18,400 → 15,100: (−3,300 ÷ 18,400) × 100 = −17.9%

Trap 1: Asymmetric Reversals

Gains and losses are not mirror images. A stock that drops 50% must gain 100% to recover. A metric up 25% only needs to fall 20% to give it all back. The base shifts with every move — which is why "down 30%, then up 30%" leaves you 9% below where you started (0.70 × 1.30 = 0.91).

Trap 2: Percentage Points vs Percent

A conversion rate improving from 2% to 3% is a 1 percentage-point gain but a 50% relative improvement. Marketers report the 50%; finance wants the point change; both are true. State which one you mean, and when reading reports, check which one the author meant.

Trap 3: Small Bases, Big Headlines

"Sales up 400%!" — from 2 units to 10. Percentage change amplifies movement on tiny bases into impressive-sounding numbers. Pair every percentage with its absolute values; this calculator displays both for exactly that reason.

Everyday Uses

Business reporting — MoM and YoY revenue, traffic, and conversion movements.
Investing — position gains and losses, and the recovery percentage required after a drawdown.
Pricing — the real percentage impact of a price adjustment.
Fitness and habits — progress measured against a starting baseline.

Free and Instant

Unlimited calculations locally in your browser — no account, nothing stored.

Percentage Change Calculator

Result