ToolerWork
Biology

ORF Finder

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

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. Enter unambiguous DNA

    Paste A/C/G/T DNA written 5′→3′.

  2. Set the scan

    Choose strands, minimum protein length and whether to include end-truncated candidates.

  3. Inspect candidates

    Select an ORF for its protein, or download the coordinate report.

Why ToolerWork?

Private by design

Sequence calculations run inside your browser.

Clear assumptions

Strand direction, code table and approximation limits are explained.

Related Tools

View All
DNA to Protein Translator

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

Reverse Complement Generator

Generate the reverse complement of DNA, including IUPAC ambiguity codes.

DNA Sequence Analyzer

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

Protein Molecular Weight Calculator

Estimate average and monoisotopic protein mass from a standard one-letter amino acid sequence.

Why use this tool?

  • Scan three or six frames with an explicit ATG-start rule.
  • Inspect overlapping starts and strand-aware coordinates.
  • Separate complete ORFs from candidates missing a final stop.

Method & assumptions

Each ATG is paired with its first in-frame TAA, TAG or TGA. Nested ATG starts are included. Optional partial ORFs extend to the last complete codon at the strand end. Coordinates are 1-based, inclusive, and refer to the input strand with start ≤ end; reverse-strand translation runs from end toward start. Nucleotide lengths include a terminal stop; protein lengths exclude it. Results retain the first 1,000 candidates in frame scan order (+1,+2,+3,−1,−2,−3). This is not gene annotation and does not splice introns.

References: NCBI genetic codes

Explore all 10 biology tools →

Frequently asked questions

Does an ORF prove that a sequence is a gene?

No. ORFs occur by chance. These are sequence candidates and need biological evidence, annotation or experimental support.

Are alternative start codons included?

No. This finder starts only at ATG and uses the standard-code stops. It does not use GTG, TTG or organism-specific initiation rules.

How are reverse-strand coordinates reported?

Both endpoints refer to the original input and are sorted low to high. A negative frame indicates translation from the higher coordinate toward the lower coordinate.

What is a partial ORF?

Here it means an ATG-start candidate without an in-frame stop before the sequence ends. Only complete triplets are included. Candidates missing their initial start are not reported.

Why are ambiguous bases rejected?

An unknown base might create or remove a start or stop. The finder requires A/C/G/T so it does not report falsely definite ORF boundaries across unknown sequence.