DNA and RNA Concentration Calculator (A260)
Enter your A260 reading and dilution to get the concentration and yield.
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DNA and RNA Concentration Calculator (A260) by TheCalcTools
How the DNA and RNA Concentration Calculator (A260) works
An A260 of 1.0 (1 cm path) corresponds to about 50 µg/mL of double-stranded DNA, 40 µg/mL of RNA and 33 µg/mL of single-stranded DNA. Multiply by any dilution you made before measuring.
A260/A280 near 1.8 for DNA and 2.0 for RNA indicates low protein contamination.
The formula
Worked example
Using the default values shown in the calculator:
| Sample type | Double-stranded DNA (50 µg/mL per A260) |
|---|---|
| A260 | 0.25 |
| Dilution factor | 50 |
| A280 (optional) | 0.13 |
| Sample volume (µL) | 50 |
| Path length (cm) | 1 |
- 0.25 × 50 × 50 = 625.0 µg/mL.
- In 50 µL that is 31.250 µg; A260/A280 = 1.92.
Result:
| Concentration (µg/mL = ng/µL) | 625.00 |
|---|---|
| Total yield (µg) | 31.250 |
| A260/A280 ratio | 1.92 |
| Purity check | Good purity |
Frequently asked questions
Why is my NanoDrop reading different?
Micro-volume instruments normalise to a 1 cm path automatically; enter path length 1 for their values. Low concentrations (below about 2 ng/µL) are unreliable.
Sources and further reading
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This calculator gives estimates for information only. Check important results independently before you rely on them. See our disclaimer.