CSS calc() Builder
Build complex CSS calc() expressions visually. Combine different units and operations for responsive layouts.
calc(100% - 20px)Container (300px)
Width Result
≈ 80 units
Operations
1
.element {
width: calc(100% - 20px);
}:root {
--custom-width: calc(100% - 20px);
}
.element {
width: var(--custom-width);
}calc(100% - 20px)calc(100% - 20px)calc(100% - 20px)calc(100% - 20px)calc(100% - 20px)About CSS calc()
The CSS calc() function allows you to perform mathematical calculations when defining CSS property values. It's incredibly powerful for creating responsive layouts and combining different units.
You can use calc() with any CSS property that accepts length, angle, time, frequency, or number values. Common use cases include fluid widths, responsive spacing, and dynamic sizing.
Supported Operations
calc(100% + 20px)calc(100vw - 40px)calc(50% × 2)calc(100% ÷ 3)Important Notes
- Spaces required: Always include spaces around + and − operators
- Unit mixing: You can combine different units (px, %, rem, etc.)
- Order of operations: Multiplication and division happen before addition and subtraction
- Browser support: Well supported in all modern browsers
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