Absorbance at 280 nm to micrograms per milliliter
Type a value in A280 to get it in µg/mL instantly.
1,000µg/mL
That's about the same as a working solution. A 20 µL sample at that concentration holds about 20 µg of protein.
What it means
How much protein is that?
A280 assumes a 1 cm path length and a protein with ordinary aromatic content. Nucleic acid contamination absorbs at 280 too and inflates the reading.
The math
How to convert A280 to µg/mL
Beer–Lambert, rearranged: mg/mL = A280 ÷ extinction coefficient, for a 1 cm path. The figures below use the protein selected above.
Example: 1 A280 = 1,000 µg/mL.
The table below is for Unknown protein (A280 = 1.0 per mg/mL).
Every unit
Your concentration in every unit
Tables
A280 to µg/mL conversion table
| A280 | µg/mL |
|---|---|
| 0.01 A280 | 10 µg/mL |
| 0.05 A280 | 50 µg/mL |
| 0.1 A280 | 100 µg/mL |
| 0.25 A280 | 250 µg/mL |
| 0.5 A280 | 500 µg/mL |
| 1 A280 | 1,000 µg/mL |
| 2 A280 | 2,000 µg/mL |
| 5 A280 | 5,000 µg/mL |
| 10 A280 | 10,000 µg/mL |
| 20 A280 | 20,000 µg/mL |
| 50 A280 | 50,000 µg/mL |
µg/mL to A280 conversion table
| µg/mL | A280 |
|---|---|
| 0.01 µg/mL | 1×10⁻⁵ A280 |
| 0.05 µg/mL | 5×10⁻⁵ A280 |
| 0.1 µg/mL | 0.0001 A280 |
| 0.25 µg/mL | 0.00025 A280 |
| 0.5 µg/mL | 0.0005 A280 |
| 1 µg/mL | 0.001 A280 |
| 2 µg/mL | 0.002 A280 |
| 5 µg/mL | 0.005 A280 |
| 10 µg/mL | 0.01 A280 |
| 20 µg/mL | 0.02 A280 |
| 50 µg/mL | 0.05 A280 |
Quick answers
Quick answers
- How many µg/mL is 1 A280?
- 1 A280 is 1,000 µg/mL.
- How many µg/mL is 10 A280?
- 10 A280 is 10,000 µg/mL.
The units
About these units
Absorbance at 280 nm (A280)
What the spectrophotometer reads, in a 1 cm cuvette.
Micrograms per milliliter (µg/mL)
For dilute samples and assay standards.
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