Calculator
What the CSS Validator does
CSS Validator: checks Status and Report from CSS. Example: the sample loaded on the page gives status Looks structurally OK.
Point it at CSS and it returns Status and Report. You can nudge a single number and watch the effect straight away.
Most people who open the CSS Validator are people inspecting an API response. Most of these tasks are one-liners in a terminal, but not when you are away from one.
The page holds your values in memory and forgets them the moment you close it.
The sections that follow cover the fields, the method, and one full example computed from the defaults.
What do the CSS Validator fields mean?
The CSS Validator uses 1 input. Pre-filled inputs double as documentation: each one shows what a reasonable value looks like.
| Field | What to enter | Default |
|---|---|---|
| CSS | paste or type any amount of text | body { margin: 0; color: #111; } |
How does the CSS Validator work?
Each output is derived from the inputs above in a single pass; there is no hidden state carried between runs, so the same inputs always give the same check.
Values are checked first: an out-of-range or non-numeric entry names the offending field instead of returning nonsense.
Worked example
These are the values the CSS Validator loads by default, and the result it produces from them. This is the worked example the page starts from, reproduced here so you can check the arithmetic.
| CSS | body { margin: 0; color: #111; } |
|---|
| Status | Looks structurally OK |
|---|---|
| Report | Brace balance OK. Tip: for full CSS validation use stylelint or W3C CSS validator. |
How to use it
- Paste your content into CSS.
- The result appears as you type. There is no button to press.
- You get Status and Report back.
- Copy Link puts the current inputs in the URL, so bookmarking it brings the same numbers back.
What this tool does not do
- Output follows the common convention for this format; a specific toolchain may have its own house style.
- Processing happens in your browser, so extremely large inputs are bounded by available memory.
- It assumes the values you give are already consistent with each other.
Frequently asked questions
You need CSS. Every box already holds a working value, which means a single edit is enough to get a meaningful answer.
With the values loaded when the page opens, status comes out as Looks structurally OK. The figure is derived from the inputs above, so it updates whenever they do.
No. The parsing happens in your browser, so sensitive payloads never leave your machine.
No. There is no account, no usage cap and no trial period. The site is funded by advertising rather than by charging for the tools.
The check is exact for the method described above. Where a value is rounded for display, the underlying figure keeps full precision.