2つの値の間の変化率を計算：増加、減少、または変化。
税込みまたは税抜きの最終価格を計算
元の価格に割引率を適用
最初にパーセント割引を適用し、次にドルオフクーポンを適用して最大限節約。
割引後の価格に売上税を適用
Type the original, pre-discount price. This is the list price or the price before any sale discount is applied.
Type the discount as a percentage. Common retail discounts are 10%, 20%, 25%, 30%, or 50% off.
Get the sale price, the dollar amount saved, and the effective percentage off (which is slightly different for stacked discounts).
For related calculations, try our percentage calculator.
変化率 = (新 - 旧) ÷ 旧 × 100：
| 旧 → 新 | 変化率 | 旧 → 新 | 変化率 |
|---|---|---|---|
| 80 → 100 | +25% | 100 → 80 | -20% |
| 50 → 75 | +50% | 200 → 150 | -25% |
| 100 → 110 | +10% | 100 → 90 | -10% |
**よくある落とし穴**：25%上昇（80→100）後20%下落（100→80）しても元には戻りません。
Cross-checked against authoritative formulas (IRS, NIST, ACSM) and updated for 2025/2026 tax years and rates.
No server roundtrip. All math runs in your browser so results appear the moment you finish typing.
We never collect, store, or transmit your inputs. Every calculation runs locally in your browser.
Each calculator includes the formula, plain-English explanation, and FAQs so you understand the result.
Estimates only. Calculator results are for educational and planning purposes — not professional advice. For binding decisions on taxes, investments, health, or legal matters, consult a qualified professional.
FAQ
Everything you need to know about this calculator. Can't find what you're looking for? Email our team.
A percentage change calculator is a free math tool that finds the percentage increase or decrease between two values. Our percentage change calculator uses the formula ((new - old) / old) x 100 and shows the absolute change too. The percentage change calculator is used for stock returns, price changes, growth rates, and performance metrics.
How it works
Our percentage change calculator lets you find the percentage increase or decrease between any two numbers, in three steps.
Type the starting value - this is the baseline the percentage is calculated from. For year-over-year changes, this is last year's number.
Type the ending value. For year-over-year, this is the current year's number. The calculator uses the original as the denominator.
The result shows the absolute change and the percentage change. The sign indicates increase or decrease, and the magnitude is the strength of the change.
Sponsored