DNA Concentration Calculator (A260 Absorbance)

DNA Concentration Calculator (A260 Absorbance) | Online Free Tool | Elysia Tools

Tool usage guide

Learn when to use this tool, what it supports, and how real users apply it.

Key facts

Category: Education
Input types: number, select
Output type: json
Sample coverage: 4
API ready: Yes

Overview

The DNA Concentration Calculator estimates dsDNA or ssDNA concentration from A260 absorbance using the Beer–Lambert relationship. Enter the dilution factor and path length to get concentration in µg/mL and ng/µL, and optionally add the elution volume to calculate total DNA yield.

When to use

Estimate DNA concentration from a blank-corrected A260 measurement.
Convert a diluted spectrophotometer reading back to the original sample concentration.
Calculate total DNA yield when the elution volume is known.

How it works

1Enter the measured A260 absorbance, DNA type, dilution factor, and optical path length.
2The calculator applies concentration = A260 × dilution factor × conversion constant ÷ path length.
3It uses 50 µg/mL per OD for dsDNA and 33 µg/mL per OD for ssDNA.
4It reports µg/mL, the equivalent ng/µL value, optional total yield, and whether A260 is within the 0.1–1.5 linear range.

Use cases

Checking plasmid miniprep concentration and total yield after elution.
Estimating ssDNA oligo concentration with the ssDNA conversion constant.
Reviewing whether a diluted UV measurement falls within the stated absorbance range.

Examples

1. Plasmid miniprep concentration and yield

Molecular biology student

Background

A 1:10 diluted plasmid miniprep has an A260 reading of 0.25 from a standard 1 cm cuvette, with a 100 µL elution volume.

Problem

Calculate the original dsDNA concentration and total amount recovered.

How to use

Enter A260 0.25, select dsDNA, use a dilution factor of 10 and a 1 cm path length, then enter 100 µL for sample volume.

a260: 0.25; dnaType: dsDNA; dilutionFactor: 10; pathLengthCm: 1; sampleVolumeUl: 100; decimalPlaces: 2

Outcome

The result is 125 µg/mL, or 125 ng/µL, with a total yield of 12.5 µg. The reading is within the 0.1–1.5 linear range.

2. ssDNA measurement above the linear range

Research technician

Background

An undiluted ssDNA preparation produces an A260 reading of 1.8 in a 1 cm path-length measurement.

Problem

Estimate the concentration while checking whether the absorbance should be re-measured after dilution.

How to use

Enter A260 1.8, select ssDNA, use a dilution factor of 1 and a 1 cm path length, and leave sample volume at 0.

FAQ

What formula does the calculator use?

It uses concentration = A260 × dilution factor × DNA conversion constant ÷ path length in cm.

Which conversion constants are supported?

The calculator uses 50 µg/mL per OD for dsDNA and 33 µg/mL per OD for ssDNA.

Why is the dilution factor needed?

It converts the measured concentration of a diluted sample to the estimated concentration of the original sample.

How is total DNA yield calculated?

When sample volume is entered, total yield equals concentration in µg/µL multiplied by the elution volume in µL.

What does the linear-range check mean?

A260 values from 0.1 to 1.5 are marked within range; values above 1.5 are flagged for dilution and re-measurement.

a260: 1.8; dnaType: ssDNA; dilutionFactor: 1; pathLengthCm: 1; sampleVolumeUl: 0; decimalPlaces: 2

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Learn when to use this tool, what it supports, and how real users apply it.

Key facts

Overview

When to use

How it works

Use cases

Examples

1. Plasmid miniprep concentration and yield

2. ssDNA measurement above the linear range

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