ToolerWork
Biology

DNA Sequence Analyzer

Inspect DNA length, nucleotide counts, GC content, GC skew and approximate molecular size.

Your sequence

Paste raw letters or one FASTA record

Up to 100,000 bases or residues. Whitespace and a single FASTA header are accepted. Invalid characters are flagged.

Sequences are processed locally and are not uploaded or saved by this tool.

Your result, clearly explained

Paste a sequence or load the example, then run the tool. Your sequence stays in this browser.

How to use

  1. Paste DNA

    Use a raw sequence or one FASTA record up to 100,000 bases.

  2. Run the analysis

    Calculate nucleotide counts, GC content and sequence length.

  3. Review the report

    Inspect ambiguity, GC skew and the rough double-stranded mass estimate.

Why ToolerWork?

Private by design

Sequence calculations run inside your browser.

Clear assumptions

Strand direction, code table and approximation limits are explained.

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GC Content Calculator

Calculate DNA GC percentage, AT percentage and base counts with clear handling of ambiguous bases.

DNA to Protein Translator

Translate DNA into amino acids in any of six reading frames using the standard genetic code.

ORF Finder

Find ATG-start open reading frames on both DNA strands, with coordinates and translated proteins.

Why use this tool?

  • Check composition and length before translation or ORF analysis.
  • Spot ambiguous positions before interpreting derived statistics.
  • Download one report with counts, percentages and assumptions.

Method & assumptions

Length includes every accepted IUPAC position. GC and AT percentages use only A/C/G/T. GC skew is (G − C) / (G + C). The rough double-stranded DNA mass uses 660 Da per base pair; it is a length-based estimate, not an exact oligonucleotide mass calculation.

References: NCBI genetic codes

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Frequently asked questions

Which statistics are included?

The report includes length, A/T/G/C counts, ambiguous count, known-base GC and AT percentages, GC skew and an approximate double-stranded mass.

How is DNA length reported?

The input strand is counted in nucleotides. For the double-stranded mass estimate, each input position is treated as one base pair in a matching duplex.

What does GC skew mean?

GC skew compares G with C: (G − C) / (G + C). It is undefined when both counts are zero. It is a composition statistic, not a gene prediction.

Is the DNA mass exact?

No. The 660 Da-per-base-pair approximation does not account for actual base composition, end groups, counterions or chemical modifications.

Can I analyze more than one FASTA entry?

Use one record at a time. Multiple headers are rejected to avoid joining unrelated sequences and reporting misleading statistics.