Percentage Calculator

How it works

• A is ?% of B = A ÷ B × 100.
• Percent change = (new − old) ÷ old × 100. A 20% drop needs a 25% rise to recover.
• Korean prices include 10% VAT; the VAT part is price ÷ 11.

FAQ

How do I calculate percentage change?

(New − old) ÷ old × 100. From 80 to 100 is +25%.

Worked example

Examples: 30 is 30 ÷ 120 × 100 = 25% of 120. A rise from 80 to 100 is (100 − 80) ÷ 80 = +25%, but a fall from 100 to 80 is −20% because the base is 100. A ₩50,000 item at 20% off costs ₩40,000.

Working back to the original price: if you paid ₩35,000 after a 30% discount, the original price was ₩35,000 ÷ 0.7 = ₩50,000 — not ₩35,000 plus 30% (₩45,500). The same logic applies to salaries: a 10% raise followed by a 10% pay cut leaves you 1% below where you started. Use the "% change" tab whenever you compare two values and want to know how far one moved from the other.

Common mistakes

• Percent and percentage points differ: a rate rising from 3% to 4% is up 1 percentage point, or about 33% in relative terms.
• 20% off followed by another 10% off is 28% off in total, not 30% (0.8 × 0.9 = 0.72).
• A 50% gain followed by a 50% loss leaves you at 75% of where you started.
• A change from zero has no percentage.
• Rounding too early changes the answer.

Explanation checked on 2026-10-30 · Spotted an outdated value? Tell us