Using CSS math functions

In the first two of our three examples above, we want to set the style of an element according to the result of an addition or subtraction operation. This is exactly one of the use cases for calc().

The calc() function lets you specify CSS property values using addition, subtraction, multiplication, and division. It is often used to combine two CSS values that have different units, such as % and px.

The calc() math function takes a mathematical expression as a parameter and returns the result of that expression, e.g.:

property: calc(expression);

Click on the play icon below to see the calc() example in the code playground and try it for yourself.

div {
  background-color: black;
  margin: 4px 0;
  width: 100%;
}

div > code {
  display: block;
  background-color: red;
  color: white;
  height: 48px;
}

.calc1 > code {
  /* Output width: `110px` */
  width: calc(10px + 100px);
}

.calc2 > code {
  /* Output width: `10em` */
  width: calc(2em * 5);
}

.calc3 > code {
  /* Output width: Depends on the container's width */
  width: calc(100% - 32px);
}

.calc4 > code {
  --predefined-width: 100%;
  /* Output width: Depends on the container's width */
  width: calc(var(--predefined-width) - calc(16px * 2));
}

There are cases where we don't want the value of a CSS property to exceed a certain number. Say, for example, we want the width of our content container to be the smaller of "the full width of our screen" and "500 pixels." In those cases, we can use the CSS math function min().

The min() math function takes a set of comma-separated values as arguments and returns the smallest of those values, e.g.:

property: min(<first value>, <second value>, <third value>, ...);

This function is often used to compare two CSS values that have different units, such as % and px.

Click on the play icon below to see the min() example in the code playground and try it for yourself.

div {
  background-color: black;
  margin: 4px 0;
  width: 100%;
}

div > code {
  display: block;
  background-color: darkblue;
  color: white;
  height: 48px;
}

.min1 > code {
  /* Output width: Depends on the container's width; */
  /* on this page, likely to be `50%` of the container's width */
  width: min(9999px, 50%);
}

.min2 > code {
  /* Output width: Depends on the container's width; */
  /* on this page, likely to be `100%` of the container's width */
  width: min(9999px, 100%);
}

.min3 > code {
  /* Output width: Depends on the container's width; */
  /* on this page, likely to be `120px` of the container's width */
  width: min(120px, 150px, 90%);
}

.min4 > code {
  /* Output width: Depends on the container's width; */
  /* on this page, likely to be `80px` of the container's width */
  width: min(80px, 90%);
}

Similar to min(), sometimes we don't want the value of a CSS property to go below a certain number. For example, we might want the width of our content container to be the larger of "the full width of our screen" and "500 pixels." In those cases, we can use the CSS math function max().

The max() math function takes a set of comma-separated values as arguments and returns the largest of those values, e.g.:

property: max(<first value>, <second value>, <third value>, ...);

This function is often used to compare two CSS values that have different units, such as % and px.

Notice the similarities and differences between the examples for min() and max().

Click on the play icon below to see the max() example in the code playground and try it for yourself.

div {
  background-color: black;
  margin: 4px 0;
  width: 100%;
  height: 48px;
}

div > code {
  display: block;
  background-color: darkmagenta;
  color: white;
  height: 48px;
}

.max1 > code {
  /* Output width: Depends on the container's width; */
  /* on this page, likely to be `50%` of the container's width */
  width: max(50px, 50%);
}

.max2 > code {
  /* Output width: Depends on the container's width; */
  /* on this page, likely to be `100%` of the container's width */
  width: max(50px, 100%);
}

.max3 > code {
  /* Output width: Depends on the container's width; */
  /* on this page, likely to be `90%` of the container's width */
  width: max(20px, 50px, 90%);
}

.max4 > code {
  /* Output width: Depends on the container's width; */
  /* on this page, likely to be `80%` of the container's width */
  width: max(80px, 80%);
}

We can combine the functions of min() and max() by using clamp(). The clamp() math function takes a minimum value, the value to be clamped, and the maximum value as arguments, e.g.:

property: clamp(<minimum value>, <value to be clamped>, <maximum value>);

• If the value to be clamped is less than the passed minimum value, the function will return the minimum value.
• If the value to be clamped is greater than the passed maximum value, the function will return the maximum value.
• If the value to be clamped is between the passed minimum and maximum values, the function will return the original value to be clamped.

This function is often used to compare two CSS values that have different units, such as % and px.

Click on the play icon below to see the clamp() example in the code playground and try it for yourself.

div {
  background-color: black;
  margin: 4px 0;
  width: 100%;
  height: 48px;
}

div > code {
  display: block;
  background-color: darkgreen;
  color: white;
  height: 48px;
}

.clamp1 > code {
  /* Output width: Depends on the container's width; */
  /* on this page, likely to be `20%` of the container's width */
  width: clamp(20%, 1px, 80%);
}

.clamp2 > code {
  /* Output width: Depends on the container's width; */
  /* on this page, likely to be `90%` of the container's width */
  width: clamp(10%, 9999px, 90%);
}

.clamp3 > code {
  /* Output width: `125px` */
  width: clamp(125px, 1px, 250px);
}

.clamp4 > code {
  /* Output width: `150px` */
  width: clamp(25px, 9999px, 150px);
}

When laying out and styling DOM elements, the four basic math functions calc(), min(), max(), and clamp() are often sufficient. However, for advanced uses like mathematics learning materials, 3D visualizations, or CSS animations, you may consider using:

• Stepped value functions
  • round(): calculates a value given a rounding strategy
  • mod(): calculates the remainder of a division operation with the same sign as the divisor
  • rem(): calculates the remainder of a division operation with the same sign as the dividend
• Trigonometric functions
  • sin(): calculates the trigonometric sine of a number
  • cos(): calculates the trigonometric cosine of a number
  • tan(): calculates the trigonometric tangent of a number
  • asin(): calculates the trigonometric inverse sine of a number
  • acos(): calculates the trigonometric inverse cosine of a number
  • atan(): calculates the trigonometric inverse tangent of a number
  • atan2(): calculates the trigonometric inverse tangent given two numbers
• Exponential functions
  • pow(): calculates a number raised to the power of another number
  • sqrt(): calculates the square root of a number
  • hypot(): calculates the square root of the sum of the squares of the given numbers
  • log(): calculates the logarithm of a number (with e as the default base)
  • exp(): calculates e of another number
• Sign functions
  • abs(): calculates the absolute value of a number
  • sign(): calculates the sign (positive, negative, or zero) of a number

• You can use CSS math functions to create responsive user interfaces without writing any JavaScript code.
• CSS math functions can sometimes be used instead of CSS media queries to define layout breakpoints.
• In 2023, members of the Interop Project selected "CSS Math Functions" as a focus area of improvement. This means that browser vendors are working together to ensure that CSS math functions perform the same across browsers and devices.