DNA Base Pair Calculator
Instantly analyze DNA sequences for GC content, molecular weight, and complementary strands. Essential for researchers, students, and biologists.
Analyze Your DNA Sequence
Enter your nucleotide sequence below to instantly calculate base composition, GC percentage, estimated molecular weight, and the complementary strand.
Sequence Parameters
Input your DNA sequence and molecule type
Sequence Analysis
Composition and physical properties
DNA Base Pairing Rules
Chargaff’s rules and average molecular weights for standard DNA nucleotides.
| Nucleobase | Abbreviation | Pairs With | Avg. MW (Da) |
|---|---|---|---|
| Adenine | A | Thymine (T) | 313.21 |
| Thymine | T | Adenine (A) | 304.20 |
| Cytosine | C | Guanine (G) | 289.18 |
| Guanine | G | Cytosine (C) | 329.21 |
DNA Analysis FAQ
Everything you need to know about DNA sequence analysis, GC content, and molecular weight calculations.
GC content is the percentage of nitrogenous bases in a DNA molecule that are either guanine (G) or cytosine (C). It is a critical factor in determining the melting temperature (Tm) and stability of the DNA double helix, as G-C pairs form three hydrogen bonds compared to the two formed by A-T pairs.
For single-stranded DNA (ssDNA), the molecular weight is calculated by summing the individual weights of each nucleotide (A ≈ 313.2 Da, T ≈ 304.2 Da, C ≈ 289.2 Da, G ≈ 329.2 Da) and subtracting 61.96 Da for the terminal phosphate and hydroxyl groups. For double-stranded DNA (dsDNA), an average of 650 Daltons per base pair is commonly used.
A complementary DNA strand is formed by pairing each base in the original sequence with its specific partner: Adenine (A) pairs with Thymine (T), and Cytosine (C) pairs with Guanine (G). This follows Chargaff’s rules of base pairing.
Yes. The calculator automatically ignores spaces and converts all lowercase letters (a, t, c, g) to uppercase before performing the analysis. However, any characters other than A, T, C, and G will trigger an error.