The container size is the 100% reference — for example, screen width, a parent layout block, or a canvas in a graphics editor.
Result
This page has no server side at all. The table you paste is parsed by JavaScript inside your own browser, the chart is drawn on a canvas element on your machine, and the export file is assembled locally. Nothing is uploaded, stored or written to any log. You can disconnect from the network after the page has loaded and everything will still work — which is the simplest way to verify the claim yourself.
Facts and limits of this method
| % → px formula | px = (percent / 100) × container size |
|---|---|
| px → % formula | percent = (px / container size) × 100 |
| Example | 50% of a 1920 px container = 960 px |
When it misleads you
- The result depends entirely on the given container size — if the container size changes (for example, in responsive layout on a different screen), the same percentage will correspond to a different number of pixels.
- The converter performs a purely arithmetic calculation and doesn't account for CSS rendering specifics (such as box-sizing, padding, borders), which can affect an element's actual visible size.
- The result is rounded to 2 decimal places, which is usually sufficient for practical layout work, even though real CSS pixels aren't fractional for most properties.
- The container size value must be positive — the converter won't produce a result for a zero or negative container size.
How it is calculated
To convert percent to pixels, the entered percentage is divided by 100 and multiplied by the container size, giving the container's share in pixels.
To convert pixels to percent, the entered pixel value is divided by the container size and multiplied by 100, giving the percentage share.
The container size is set manually for each calculation, since a percentage is a relative quantity and has no meaning without a reference base.
The result is rounded to 2 decimal places and updates instantly whenever any parameter changes.
Questions and answers
Why do I need a container size if I just want to convert percent to pixels?
Because a percentage is a relative quantity: 50% of a 1920 px container and 50% of an 800 px container are different pixel counts (960 px and 400 px respectively).
Can this be used for website layout calculations?
Yes, this is a common task when converting responsive layout (in percentages) to fixed pixel sizes for a specific screen resolution, and vice versa.
Does the converter account for CSS block padding and borders?
No, this is a purely mathematical share-of-total calculation — box-sizing, padding and border need to be accounted for separately depending on the specific CSS box model.
Is my data sent anywhere?
No, the whole calculation runs in your browser.