# CSS: “width”: The types are incompatible. > Canonical HTML version: https://rocketvalidator.com/html-validation/css-width-the-types-are-incompatible > Attribution: Rocket Validator (https://rocketvalidator.com) > License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/) This error originates from CSS validation, not HTML element validation. It typically appears when the validator encounters a `width` value in a `style` attribute or ` ``` ### Correct: Valid length value in a ` ``` ### Note on the HTML `width` attribute Don't confuse CSS `width` with the HTML `width` attribute. The HTML `width` attribute on elements like ``, `