Percentage Calculator: How to Calculate Tips, Discounts & Grades

September 5, 2026 · 4 min read

Percentages come up in daily life more than you might think. Figuring out a 18% tip at dinner. Calculating how much you save with a 30% off coupon. Checking if your test score of 42 out of 55 is a passing grade. A percentage calculator handles all of these instantly.

Calculate Tips Quickly

For a $85 dinner with 18% tip: 10% is $8.50, plus another 10% is $8.50 — so 20% would be $17. For 18%, take 20% ($17) minus 2% ($1.70) = $15.30. Or just type the numbers into a calculator. For groups, divide the total (bill + tip) by the number of people.

Shopping Discounts

A $120 jacket is 35% off. The discount amount is $120 × 0.35 = $42. The sale price is $120 - $42 = $78. Double discounts are trickier — 20% off plus an additional 15% off is NOT 35% off. It is 20% off first ($96), then 15% off that ($81.60). The actual combined discount is 32%.

Test Scores and Grades

You scored 38 out of 45 on a test. Your percentage is (38 / 45) × 100 = 84.4%. To find out what score you need on the final exam to get an A in the class, work backwards from the grade threshold. If you need 90% overall and the final is worth 40% of your grade, the calculator handles the algebra for you.

Everyday Percentage Scenarios

Battery at 23% — how many minutes of a 12-hour full charge is that? About 2 hours 46 minutes. Your internet speed test shows 340 Mbps out of a 500 Mbps plan — you are getting 68% of what you pay for. Percentages turn raw numbers into meaningful comparisons.

Try It Now

Our free Percentage Calculator handles this instantly — no signup, no limits.

Also useful: our Discount Calculator for related calculations.