Light reflectance value is the proportion of visible light a surface reflects, on a scale from 0 (black) to 100 (white). It is used to check visual contrast for accessible design.

What LRV difference is needed for visual contrast?

BS 8300-2:2018 treats a difference of 30 LRV points between adjacent surfaces, such as a wall and floor or a door and its surround, as sufficient. 20 points can be acceptable where the surfaces are lit to 200 lux or more, and 15 points is the guide for door ironmongery against the door.

Can I get an accurate LRV from a hex or RGB colour?

Only an estimate. LRV from a screen colour is derived from its calculated luminance, and screens, printing and paint finishes all vary. For compliance, use the LRV published by the paint or material manufacturer.

Are RAL colours shown on screen accurate?

No screen value is an exact RAL colour. The hex values here are widely used approximations, so check against a physical RAL Classic swatch before specifying.

What contrast ratio does WCAG require for text?

WCAG AA requires a contrast ratio of at least 4.5:1 for normal text and 3:1 for large text. AAA raises these to 7:1 and 4.5:1.

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Indicative onlyThese tools provide indicative calculations only. No warranty is given as to the accuracy, completeness or fitness for purpose of any output. Using this site does not create a professional relationship or duty of care between brickdims and the user. Results must not be used as a substitute for professional advice, site-specific assessment, or formal compliance sign-off. Building regulations are subject to change, so always verify against the current editions of the relevant Approved Documents and consult a building control officer where required. brickdims accepts no liability for any loss, damage or non-compliance arising from reliance on these tools, to the fullest extent permitted by law. If any part of these terms is found unenforceable, the remaining terms continue to apply. These terms are governed by the laws of England and Wales. By using this site you accept these terms.

Colour converter

Convert between HEX, RGB, HSL and CMYK. Match to RAL Classic. Explore colour harmonies.

Results from brickdims.com tools are indicative only. Using this site does not create a professional relationship or duty of care. Not a substitute for professional advice or formal compliance sign-off.

Colour input

HEX#

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CMYK,,,

RAL® is a registered trademark of RAL gGmbH. Hex values are community-sourced approximations and the closest match is determined by colour distance (ΔE). On-screen colours will differ from physical RAL fan decks.

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Colour palette

Complementary colours

Shades

Complementary

Analogous

Triadic

Split-complementary

Tetradic

Contrast - LRV & WCAG 2.1

Uses the palette colours; add the current colour with the + button. Every pair is rated two ways: LRV point difference between surfaces (AD M / BS 8300-2:2018) and WCAG 2.1 contrast ratio for text. AA = 4.5:1 normal / 3:1 large text. AAA = 7:1 normal / 4.5:1 large text.

Colours - ranked by LRV

Comparisons

Add at least two colours to the palette to see contrast ratings.

LRV difference key: 30 points minimum between adjacent critical surfaces. 20 points acceptable where surface illuminance is 200 lux or more. 15 points minimum for door ironmongery against the door surface.

On-screen LRVs are nominal values derived from the display colour. Use manufacturers' measured LRVs for compliance checks.