Colour Difference Calculator
Create labelled comparison scenarios. Choose each colour’s model and white point independently, then inspect both colour differences and the complete calculation report.
HEX: #RGB or #RRGGBB, opaque only. sRGB: R, G, B in 0–255. Lab: L, a, b separated by commas. Lab D50 and Lab D65 declare reference white; all comparisons use Lab D50. Relative Lab input uses L 0–100; a/b and positive factors have no additional colour-specific cap within the stated decimal parser bounds.
sRGB is linearized at D65 and Bradford adapted to D50. Lab D65 is converted via XYZ and adapted to D50; Lab D50 is used directly. ΔEab is Euclidean; CIEDE2000 uses the entered kL/kC/kH (1/1/1 is the reference setting). No universal pass threshold or display calibration is inferred.
Check every scenario: HEX needs 3 or 6 digits; sRGB needs three channels 0–255; Lab needs L 0–100 and finite a/b coordinates. Decimal tokens: at most 24 characters and 15 significant digits; exponents −12…12. Factors must be finite and greater than zero; calculation intermediates must remain finite. Labels: 1–80 characters. Maximum 100 scenarios.
Calculations use IEEE 754 double precision. The report retains shortest round-trip numeric values, not mathematically exact real numbers. Hue angles are degrees; exact zero chroma uses the defined zero branch and hue differences wrap at 180°. Near 180° the formula can be discontinuous.
All calculations and exports stay in this browser.
A QUICK WALKTHROUGH
How to use this tool
- Enter each colour as HEX, three sRGB channels or three Lab coordinates.
- Declare the Lab white point and positive kL, kC and kH factors for each scenario.
- Calculate all scenarios, inspect intermediate values, then copy or download the frozen report.
Models and limits
HEX: #RGB or #RRGGBB, opaque only. sRGB: R, G, B in 0–255. Lab: L, a, b separated by commas. Lab D50 and Lab D65 declare reference white; all comparisons use Lab D50. Relative Lab input uses L 0–100; a/b and positive factors have no additional colour-specific cap within the stated decimal parser bounds. sRGB is linearized at D65 and Bradford adapted to D50. Lab D65 is converted via XYZ and adapted to D50; Lab D50 is used directly. ΔEab is Euclidean; CIEDE2000 uses the entered kL/kC/kH (1/1/1 is the reference setting). No universal pass threshold or display calibration is inferred. Check every scenario: HEX needs 3 or 6 digits; sRGB needs three channels 0–255; Lab needs L 0–100 and finite a/b coordinates. Decimal tokens: at most 24 characters and 15 significant digits; exponents −12…12. Factors must be finite and greater than zero; calculation intermediates must remain finite. Labels: 1–80 characters. Maximum 100 scenarios.
Full precision report
Calculations use IEEE 754 double precision. The report retains shortest round-trip numeric values, not mathematically exact real numbers. Hue angles are degrees; exact zero chroma uses the defined zero branch and hue differences wrap at 180°. Near 180° the formula can be discontinuous.
GOOD TO KNOW
Common questions
Are these accessibility or acceptance scores?
No. ΔE describes a colour difference under the declared model and factors. It does not establish text contrast, a calibrated display result or an acceptance tolerance.