Web ToolBox

Percentage・PX Calculator

Convert percentage and PX based on parent size

Conversion Settings

Base size for calculations
Presets
Decimal Places
Relative to parent element
Formula
(50% ÷ 100) × 1000px = 500.0px
Absolute size
Formula
(500px ÷ 1000px) × 100 = 50.0%

Common Conversion Table

Parent Size: 1000px

PercentagePX Value
5.0%
50.0px
10.0%
100.0px
20.0%
200.0px
25.0%
250.0px
33.3%
333.3px
50.0%
500.0px
66.7%
666.7px
75.0%
750.0px
80.0%
800.0px
90.0%
900.0px
100.0%
1000.0px

What is Percentage・PX Calculator?

A tool that converts between percentage (%) and pixels (px) in CSS. Based on a parent element's width, you can calculate how many pixels a percentage equals, or what percentage a pixel value represents. Useful when translating pixel values from design tools like Figma into code.

Key Features

  • Bidirectional conversion: Percentage→PX and PX→Percentage
  • Adjustable parent size: Change to any size
  • Size presets: One-click selection of common breakpoints (320px, 768px, 1440px, etc.)
  • Formula display: See the calculation process
  • Copy function: One-click copy to clipboard
  • Decimal precision: Choose 0–2 decimal places
  • Preset table: Common percentage conversions at a glance

How to Use

  1. Enter parent element size or select from presets (default is 1000px)
  2. Input either percentage or pixel value
  3. The other value calculates automatically
  4. Click copy button to save result to clipboard

Examples

Converting a 720px element from your design tool to a percentage for a 1200px container. Enter 720px and you'll get 60%.

Finding the actual pixel width of a 33.33% column in a responsive grid. With a 1000px parent, that's 333.3px.

Changing a sidebar from 25% to a fixed width. For a 1440px container, that's 360px.

Formulas

Percentage to Pixels conversion:

px = (Percentage ÷ 100) × Parent Size

Example: 50% → (50 ÷ 100) × 1000px = 500px

Pixels to Percentage conversion:

% = (Pixels ÷ Parent Size) × 100

Example: 500px → (500 ÷ 1000px) × 100 = 50%

Preset Conversion Table

Check common percentage conversions at a glance.

PercentageWhen Parent is 1000px
5%50px
10%100px
25%250px
33.33%333.3px
50%500px
66.67%666.7px
75%750px
100%1000px

Table values update automatically when you change the parent size.

FAQ

How should I choose decimal precision?

For layout work, 1 or 2 decimal places is enough. Pick 0 if you want clean integers, or 2 for finer adjustments.

What should I use for parent element size?

The actual container or viewport width. Try common breakpoints (320px, 768px, 1024px, 1440px) to visualize dimensions across different devices.