font-weight
The font-weight
CSS property sets the weight (or boldness) of the font. The weights available depend on the font-family
that is currently set.
Try it
Syntax
/* <font-weight-absolute> keyword values */
font-weight: normal;
font-weight: bold;
/* <font-weight-absolute> numeric values [1,1000] */
font-weight: 100;
font-weight: 200;
font-weight: 300;
font-weight: 400; /* normal */
font-weight: 500;
font-weight: 600;
font-weight: 700; /* bold */
font-weight: 800;
font-weight: 900;
/* Keyword values relative to the parent */
font-weight: lighter;
font-weight: bolder;
/* Global values */
font-weight: inherit;
font-weight: initial;
font-weight: revert;
font-weight: revert-layer;
font-weight: unset;
The font-weight
property is specified using either a <font-weight-absolute>
value or a relative weight value, as listed below.
Values
normal
-
Normal font weight. Same as
400
. bold
-
Bold font weight. Same as
700
. <number>
-
A
<number>
value between 1 and 1000, both values included. Higher numbers represent weights that are bolder than (or as bold as) lower numbers. This allows fine-grain control for variable fonts. For non-variable fonts, if the exact specified weight is unavailable, a fallback weight algorithm is used — numeric values that are divisible by 100 correspond to common weight names, as described in the Common weight name mapping section below. lighter
-
One relative font weight lighter than the parent element. Note that only four font weights are considered for relative weight calculation; see the Meaning of relative weights section below.
bolder
-
One relative font weight heavier than the parent element. Note that only four font weights are considered for relative weight calculation; see the Meaning of relative weights section below.
Fallback weights
If the exact weight given is unavailable, then the following rule is used to determine the weight actually rendered:
- If the target weight given is between
400
and500
inclusive:- Look for available weights between the target and
500
, in ascending order. - If no match is found, look for available weights less than the target, in descending order.
- If no match is found, look for available weights greater than
500
, in ascending order.
- Look for available weights between the target and
- If a weight less than
400
is given, look for available weights less than the target, in descending order. If no match is found, look for available weights greater than the target, in ascending order. - If a weight greater than
500
is given, look for available weights greater than the target, in ascending order. If no match is found, look for available weights less than the target, in descending order.
Note: The fallback weight algorithm is only used for rendering. The computed value of the property is still the specified value.
Meaning of relative weights
When lighter
or bolder
is specified, the below chart shows how the absolute font weight of the element is determined.
Note that when using relative weights, only four font weights are considered — thin (100), normal (400), bold (700), and heavy (900). If a font family has more weights available, they are ignored for the purposes of relative weight calculation.
Inherited value | bolder |
lighter |
---|---|---|
100 | 400 | 100 |
200 | 400 | 100 |
300 | 400 | 100 |
400 | 700 | 100 |
500 | 700 | 100 |
600 | 900 | 400 |
700 | 900 | 400 |
800 | 900 | 700 |
900 | 900 | 700 |
Common weight name mapping
The numerical values 100
to 900
roughly correspond to the following common weight names (see the OpenType specification):
Value | Common weight name |
---|---|
100 | Thin (Hairline) |
200 | Extra Light (Ultra Light) |
300 | Light |
400 | Normal (Regular) |
500 | Medium |
600 | Semi Bold (Demi Bold) |
700 | Bold |
800 | Extra Bold (Ultra Bold) |
900 | Black (Heavy) |
950 | Extra Black (Ultra Black) |
Variable fonts
While many fonts have a particular weight corresponding to one of the numbers in Common weight name mapping, most variable fonts support a range of weights providing much finer granularity, giving designers and developers more control over the chosen weight.
For TrueType or OpenType variable fonts, the "wght" variation is used to implement varying widths.
This demo loads with font-weight: 500;
set. Change the value of the font-weight
property to see the weight of the text change.
Accessibility
People experiencing low vision conditions may have difficulty reading text set with a font-weight
value of 100
(Thin/Hairline) or 200
(Extra Light), especially if the font has a low contrast color ratio.
Formal definition
Initial value | normal |
---|---|
Applies to | all elements and text. It also applies to ::first-letter and ::first-line . |
Inherited | yes |
Computed value | the keyword or the numerical value as specified, with bolder and lighter transformed to the real value |
Animation type | a font weight |
Formal syntax
font-weight =
<font-weight-absolute> |
bolder |
lighter
<font-weight-absolute> =
normal |
bold |
<number [1,1000]>
Examples
Setting font weights
HTML
<p>
Alice was beginning to get very tired of sitting by her sister on the bank,
and of having nothing to do: once or twice she had peeped into the book her
sister was reading, but it had no pictures or conversations in it, "and what
is the use of a book," thought Alice "without pictures or conversations?"
</p>
<div>
I'm heavy<br />
<span>I'm lighter</span>
</div>
CSS
/* Set paragraph text to be bold. */
p {
font-weight: bold;
}
/* Set div text to two steps heavier than
normal but less than a standard bold. */
div {
font-weight: 600;
}
/* Set span text to be one step lighter
than its parent. */
span {
font-weight: lighter;
}
Result
Specifications
Specification |
---|
CSS Fonts Module Level 4 # font-weight-prop |
Browser compatibility
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