#F43521
Closest named color: Vermillion (#F4320C). oklch(63% 0.228 30.3), rgb(244, 53, 33).
Aa
Black text reads best on this color (5.37:1).
About this color
#F43521 is a medium-light, vivid red. In OKLCH its lightness is 63%, its chroma 0.228 and its hue 30°. Its hue sits on the warm side of the wheel. The nearest named color is Vermillion (#F4320C), ΔE 0.009 away. Black text reads best on it, at 5.37:1.
| Hue family | Reds |
| Lightness | medium-light (63%) |
| Chroma | vivid (0.228) |
| Temperature | warm |
| Nearest name | Vermillion (#F4320C) |
| Black text | 5.37:1 |
| White text | 3.90:1 |
Values
| HEX | #F43521 |
| RGB | rgb(244, 53, 33) |
| HSL | hsl(6, 91%, 54%) |
| OKLCH | oklch(63% 0.228 30.3) |
Contrast
WCAG 2 contrast ratios are the conformance target: AA needs 4.5:1 for body text and 3:1 for large text, AAA needs 7:1. APCA Lc values are supplementary guidance from the WCAG 3 drafts.
| Pair | WCAG 2 | Result | APCA | APCA guidance |
|---|---|---|---|---|
| White text on #F43521 | 3.90:1 | AA large text | Lc -70.2 | Content text, not long reading |
| Black text on #F43521 | 5.37:1 | AA | Lc 39.4 | Non-text elements, placeholder text |
| #F43521 text on white | 3.90:1 | AA large text | Lc 64.7 | Content text, not long reading |
| #F43521 text on black | 5.37:1 | AA | Lc -37.0 | Non-text elements, placeholder text |
Tints and shades
A 50–950 scale built in OKLCH: the hue is held, lightness follows a Tailwind v4-like curve, and every step is kept inside the sRGB gamut. This color sits at step 500.
-
Step 50
50
#FFF2F0
oklch(97.1% 0.014 28)
-
Step 100
100
#FFE2DD
oklch(93.5% 0.033 29.4)
-
Step 200
200
#FFCBC1
oklch(88.5% 0.061 30.9)
-
Step 300
300
#FFA696
oklch(80.9% 0.109 30.7)
-
Step 400
400
#FC6D59
oklch(70.7% 0.179 30.2)
-
Step 500
500 (this color)
#F43521
oklch(63% 0.228 30.3)
-
Step 600
600
#D61500
oklch(55.6% 0.221 30.4)
-
Step 700
700
#B51000
oklch(49% 0.195 30.4)
-
Step 800
800
#960B00
oklch(42.7% 0.17 30.3)
-
Step 900
900
#7E0901
oklch(37.7% 0.149 30.3)
-
Step 950
950
#4A0C06
oklch(27% 0.093 30.2)
#F43521 with color blindness
Simulated with the Machado et al. (2009) model. ΔE is how far the color moves: below about 0.02 you would not notice a change.
| Vision | Seen as | Shift (ΔE) |
|---|---|---|
| Protanopia (no red cones) | #73661B | 0.245 |
| Deuteranopia (no green cones) | #A29011 | 0.221 |
| Tritanopia (no blue cones) | #FF0033 | 0.039 |
| Achromatopsia (no color) | #818181 | 0.229 |
Harmonies
Hue rotations in OKLCH that keep this color's lightness and chroma.
Complementary
The opposite hue (180°).
- #F43521
#F43521
oklch(63% 0.228 30.3)
- #009AAE
#009AAE
oklch(62.9% 0.109 210.8)
Analogous
Neighbouring hues, 30° either side.
Split complementary
The two hues beside the complement (150° and 210°).
Triadic
Three hues spaced 120° apart.
Palettes with this color
Curated palettes that contain a color within ΔE 0.04 (OKLab) of #F43521, closest first.
No curated palette has a color within ΔE 0.04 of #F43521.
Similar named colors
The eight closest entries in our named color list, with their ΔE distance.
- Vermillion #F4320C ΔE 0.009
- Orangey Red #FA4224 ΔE 0.022
- Tomato Red #EC2D01 ΔE 0.022
- Red Orange #FD3C06 ΔE 0.025
- Fire Engine Red #FE0002 ΔE 0.030
- Red #FF0000 ΔE 0.030
- Bright Red #FF000D ΔE 0.030
- Orangered #FE420F ΔE 0.031
Use #F43521 in your product
Turn it into light and dark UI roles checked for contrast, then export to Tailwind v4, shadcn/ui, CSS or design tokens.