DNA Sequence Statistics Calculator

The DNA Sequence Statistics Calculator analyzes any DNA sequence and returns key physical and chemical properties used in molecular biology workflows. Paste your DNA sequence (A, T, G, C only), select your strand type (ssDNA or dsDNA) and 5' phosphate group status, then enter your salt and DNA concentrations to calculate sequence length, GC content, molecular weight, melting temperature (Tm), extinction coefficient, and mass per picomole.

Paste your DNA sequence. Only A, T, G, C nucleotides are accepted.

Strand Type *

5' Phosphate Group *

mM

Monovalent salt concentration for Tm calculation

nM

Total DNA concentration for Tm calculation

Results

Sequence Length

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GC Content

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Molecular Weight

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Melting Temperature (Tm)

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Extinction Coefficient

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Mass per Picomole

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Frequently Asked Questions

What is GC content and why is it important?

GC content is the percentage of guanine (G) and cytosine (C) nucleotides in a DNA sequence. It affects DNA stability, melting temperature, and PCR efficiency. Higher GC content generally means higher melting temperature.

How is the melting temperature (Tm) calculated?

Tm is calculated using the nearest-neighbor method considering base-pair stacking energies, salt concentration, and DNA concentration. The formula accounts for thermodynamic parameters of each dinucleotide step.

What's the difference between single-strand and double-strand DNA molecular weight?

Double-stranded DNA has approximately twice the molecular weight of single-stranded DNA of the same sequence, plus the weight of complementary bases. The calculator adjusts the molecular weight based on your strand type selection.

How does salt concentration affect melting temperature?

Higher salt concentrations increase the melting temperature by stabilizing the DNA double helix. Monovalent salts like NaCl shield the negative charges on the DNA backbone, making denaturation require higher temperatures.

What is the extinction coefficient used for?

The extinction coefficient allows you to calculate DNA concentration from UV absorbance measurements at 260nm. It represents how strongly the DNA absorbs UV light per molar concentration.

Why does the 5' phosphate group matter for molecular weight?

Phosphate groups add significant mass to the DNA molecule. Triphosphate groups (as in cellular DNA) are heavier than monophosphate groups (common in synthetic oligos), affecting the total molecular weight calculation.

Can I analyze RNA sequences with this calculator?

This calculator is specifically designed for DNA sequences (A, T, G, C). For RNA analysis, you would need a calculator that accounts for uracil (U) instead of thymine (T) and different thermodynamic parameters.