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概要

パーセント計算機

「〇〇の何%？」「〇〇は全体の何%？」「増減率は？」の3つのよく使うパーセント計算を即解決します。

とはの使い方使用例主な使用シーンよくある質問

カテゴリ hub

データ

悩み

5

FAQ

4

クイックリンク

Hubを見る
#percentage-calculator#percent-change#percentage-of-number#math-calculator#percentage-formula

Percentage Calculator

Solve the three most common percentage questions instantly.

e.g. 15% of 200 = 30

Enter values above to calculate

解決できる問題

How do I find what percent of a number is?

Select 'What is X% of Y?' mode, enter the percentage and the total. The calculator multiplies (percentage ÷ 100) × total. For example, 15% of 60 is 9. This is useful for calculating tips, discounts, or tax.

How do I calculate percent increase or decrease?

Use the '% change' mode. Enter the original value and the new value. Percent change = ((new − original) ÷ original) × 100. An increase from 200 to 250 is a 25% increase. A drop from 200 to 150 is a 25% decrease.

How do I find what percentage one number is of another?

Use the 'X is what % of Y?' mode. Enter the part value and the total. The calculator computes (part ÷ total) × 100. For example, 45 is 30% of 150. This is useful for converting test scores or comparing parts to a whole.

How do I calculate the price after a percentage discount?

First use 'What is X% of Y?' to find the discount amount: enter the discount percentage and the original price. Then subtract that from the original price manually. For example, 30% off $80: 30% of 80 = 24, so the sale price is $80 − $24 = $56.

How do I add a sales tax percentage to a price?

Use 'What is X% of Y?' with the tax rate and pre-tax price to find the tax amount, then add it to the original price. For example, 8.5% tax on $120: 8.5% of 120 = $10.20, so total = $130.20.

よくある使用フロー

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このワークフローのガイド

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とは

パーセント計算機 とは？

The Percentage Calculator solves the three percentage questions people reach for a calculator to answer: finding a percentage of a value (what is 15% of 240?), finding what percentage one number is of another (30 is what percent of 200?), and calculating percentage change between two values (what is the percent increase from 80 to 100?).

Switch between modes with a single tap. Each mode shows only the two inputs it needs and returns the answer immediately — no formula memorization, no unit confusion, no rounding guesswork.

の使い方

パーセント計算機 の使い方

1. Select the mode that matches your question: 'What is X% of Y?', 'X is what % of Y?', or '% change from X to Y'.

2. Enter the two values in the input fields.

3. The result appears instantly below the inputs.

4. Switch modes at any time — the inputs clear automatically.

使用例

使用例

Mode: What is X% of Y?
  Percentage: 18
  Total value: 250
  Result: 45  (18% of $250 restaurant bill = $45 tip)

Mode: X is what % of Y?
  Part: 36
  Total: 144
  Result: 25%  (scored 36 out of 144 = 25%)

Mode: % change from X to Y
  Original: 80
  New: 100
  Result: +25%  (price rose from $80 to $100)

主な使用シーン

主な使用シーン

1. Shopping discounts: Find the sale price by calculating the discount percentage off the original price.

2. Test scores: Convert a raw score (34 out of 40) into a percentage grade.

3. Tax and tip: Calculate 8.5% sales tax or 20% tip on a bill amount.

4. Finance: Track portfolio growth — find the percent increase from last month's balance to this month's.

5. Business metrics: Calculate month-over-month revenue change or conversion rate shifts.

よくある質問

よくある質問

How do I calculate a percentage of a number?v
Use the 'What is X% of Y?' mode. Enter the percentage in the first field and the total value in the second. The result is (percentage ÷ 100) × total. For example, 20% of 150 = 0.20 × 150 = 30.
How do I calculate percent change?v
Use the '% change from X to Y' mode. Enter the original value and the new value. The formula is ((new − original) ÷ |original|) × 100. A positive result is an increase; negative is a decrease.
What is the difference between percent and percentage points?v
Percent (%) expresses a ratio relative to a total. Percentage points measure the arithmetic difference between two percentages. If a rate goes from 4% to 6%, that is a 2 percentage point increase, but a 50% relative increase. This calculator computes relative percent change.
Can I calculate a percentage decrease?v
Yes. Use the '% change from X to Y' mode and enter the larger number as the original and the smaller as the new value. The result will show as a decrease, displayed in red.