Recognised as Colour

#FF2121

#FF2121
Red
Dark
Nearest: Red

#FF2121 is a red with RGB values 255, 33, 33 and HSL 0°, 100%, 56%. It is a dark colour, so black text on it reaches 5.5:1 contrast (AA for normal text). The nearest named colour is Red.

Colour values

#FF2121#FF2121

HEX#FF2121

RGBrgb(255, 33, 33)

RGB (0–1)1, 0.1294, 0.1294

RGB percentages100%, 12.9%, 12.9%

HSLhsl(0, 100%, 56.5%)

HSV / HSBhsv(0, 87.1%, 100%)

CMYK0%, 87.1%, 87.1%, 0%≈naive device-independent conversion; real print needs an ICC profile

24-bit integer16,720,161

CSS custom property--colour: #FF2121;

Brightness & contrast

Relative luminance0.22458WCAG 2.x, 0 is black and 1 is white

Perceived brightness142.1 of 255ITU-R BT.601 weighting

Light or darkDark

Best text colour on this backgroundBlackcontrast 5.49:1

Contrast with white3.82:1WCAG normal text: Fail

Contrast with black5.49:1WCAG normal text: AA

Greyscale equivalent#505050

Inverted#00DEDE

Colour vision & accessibility

Normal vision Protanopia Deuteranopia Tritanopia

Protanopia#71641Cno red cones; affects about 1% of men; ΔE 83.3 from the original

Deuteranopia#A5930Cno green cones; the most common form, about 1% of men; ΔE 83.4 from the original

Tritanopia#FF0027no blue cones; rare, and affects men and women equally; ΔE 5.2 from the original

Distinguishable without hueShifts in lightness toonever rely on hue alone to carry meaning

Contrast with white, large text3.82:1WCAG large text: AA

Contrast with black, large text5.49:1WCAG large text: AAA

Named colours

Red · ΔE 10.1 Orange red · ΔE 15 Tomato · ΔE 23.5 Crimson · ΔE 25.9 Firebrick · ΔE 32.9 Coral · ΔE 35.7

Nearest named CSS colourRed (#FF0000)ΔE 10.12, a distinctly different colour

Hue familyred

CSS keyword usableNo exact keyword

Colour harmonies

base +30°+90°+120°+180°+210°+240°+270°+330°

Complementary#21FFFF

Analogous#FF2190, #FF9021

Triadic#21FF21, #2121FF

Split complementary#21FF90, #2190FF

Tetradic#90FF21, #21FFFF, #9021FF

Tints, shades & saturation

+40%+30%+20%+10%base -10%-20%-30%-40%

Lighter +40%#FFEDED

Lighter +30%#FFBABA

Lighter +20%#FF8787

Lighter +10%#FF5454

Darker −10%#ED0000

Darker −20%#BA0000

Darker −30%#870000

Darker −40%#540000

More saturated +25%#FF2121

Less saturated −25%#E33D3D

Channel breakdown

R255

G33

B33

Red255 (100%)

Green33 (12.9%)

Blue33 (12.9%)

Hue0°

Saturation (HSL)100%

Lightness56.47%

Dominant channelRed

Hex per channelR FF · G 21 · B 21

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Harmonies

Lighter and darker

Similar named colours

Also reads as

FF2121 (chemical formula)

Formula
40,313.756 g/mol
2122 atoms

FF2121 has a molar mass of 40,313.756 g/mol, made up of 2122 atoms across 1 element: 2122 × F.

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Molar mass

Molar mass40,313.756 g/mol

Total atoms per molecule2122

Distinct elements1

Mass of one molecule6.6942567 × 10^-20 g

Molecules per gram1.4938178 × 10^19

Name

NameNot in the name tablea name cannot be worked out from a formula alone: isomers share formulas, and naming depends on bonding the formula does not show

Composition by mass

F100%

Fluorine (F × 2122)40,313.756 g/mol, 100%

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Elements in this formula

Fluorine

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