Toolsified

Pricing and quick math

Percentage Calculator

Handle percent of a number, percentage change, and simple increases or decreases in one place without jumping between different formulas.

Runs in the browser No signup required Useful for pricing and budgets

Calculator

Run the percentage math

Each section answers a slightly different percentage question, so you can use the right formula without thinking about setup first.

1. What is X% of Y?

2. X is what percent of Y?

3. Percentage change

4. Add or subtract a percentage

Method

How it works

The page uses standard percentage formulas directly in the browser.

  • percent of number = rate / 100 x base
  • what percent = part / whole x 100
  • percentage change = (new - old) / old x 100
  • adjusted value = base x (1 +/- rate / 100)

Limitations: this gives the math only. You still need the right business interpretation for margin, markup, percentage points, or absolute change.

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What is the difference between percentage change and percentage points?

Percentage change measures relative movement, while percentage points describe the direct gap between two percentages.

Can I use this for discounts and markups?

Yes. The add/subtract section is useful for quick discount and markup checks.

Why does percent change fail when the starting value is zero?

Because the formula divides by the starting value, and division by zero is undefined.

How do I calculate compound percentage growth over multiple periods?

Multiply the base by (1 + rate/100) raised to the number of periods instead of adding the same percentage each time.

What is the difference between markup and margin?

Markup is the percentage added to cost, while margin is the percentage of the selling price that is profit -- so a 50% markup equals a 33.3% margin.

When should I use percentage difference instead of percentage change?

Use percentage difference when neither value is a clear baseline, such as comparing two independent measurements, and percentage change when one value came before the other.