Percent transmittance to absorbance
Type a value in %T to get it in A instantly.
2A
That's about the same as a strongly colored sample. About 1% of the light gets through.
Convert the other way: A to %T
What it means
How much light gets through?
Above about 2 the detector is measuring very little light, and stray light dominates. Dilute the sample rather than trusting the reading.
The math
How to convert %T to A
Absorbance is a logarithm of transmittance: A = −log₁₀(T), and back again %T = 10^(−A) × 100. One absorbance unit is a tenfold cut.
Example: 1 %T = 2 A.
Every unit
Your absorbance in every unit
Tables
%T to A conversion table
| %T | A |
|---|---|
| 0.01 %T | 4 A |
| 0.05 %T | 3.30103 A |
| 0.1 %T | 3 A |
| 0.3 %T | 2.52288 A |
| 0.5 %T | 2.30103 A |
| 0.7 %T | 2.1549 A |
| 1 %T | 2 A |
| 1.5 %T | 1.82391 A |
| 2 %T | 1.69897 A |
| 3 %T | 1.52288 A |
| 4 %T | 1.39794 A |
A to %T conversion table
| A | %T |
|---|---|
| 0.01 A | 97.7237 %T |
| 0.05 A | 89.1251 %T |
| 0.1 A | 79.4328 %T |
| 0.3 A | 50.1187 %T |
| 0.5 A | 31.6228 %T |
| 0.7 A | 19.9526 %T |
| 1 A | 10 %T |
| 1.5 A | 3.16228 %T |
| 2 A | 1 %T |
| 3 A | 0.1 %T |
| 4 A | 0.01 %T |
Quick answers
Quick answers
- How many A is 1 %T?
- 1 %T is 2 A.
- How many A is 10 %T?
- 10 %T is 1 A.
The units
About these units
Percent transmittance (%T)
How much light gets through, as a percentage.
Absorbance (A)
The base-ten logarithm of what is blocked. Proportional to concentration.
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