Absorbance Calculator
Convert between absorbance, transmittance, and light intensity
Calculation Mode
Key Equations
A = -log₁₀(T)
T = I / I₀
%T = T × 100
A = -log₁₀(I/I₀)
Absorbance
0.5000
Transmittance
31.62%
All Values
Absorbance (A)0.5000
Optical Density (OD)0.5000
Transmittance (%T)31.6228%
I/I₀ Ratio0.3162
Light Absorbed68.38%
Visual Representation
Incident100%
Absorbed
68.4%
Transmitted
31.6%
About Absorbance
Absorbance (A) is a measure of how much light is absorbed by a sample. It is related to transmittance by:
A = -log₁₀(T) = -log₁₀(I/I₀)
Key points:
- Absorbance is unitless (sometimes called AU - absorbance units)
- Optical density (OD) is equivalent to absorbance
- Linear range is typically A = 0.1 to 1.0
- Higher absorbance means more light absorbed