Which amino acids are supported?

All 20 standard proteinogenic amino acids (A, C, D, E, F, G, H, I, K, L, M, N, P, Q, R, S, T, V, W, Y) are supported.

What happens if my sequence contains unknown characters?

Unknown characters are flagged individually in the output and highlighted so you can identify them easily. Valid amino acids in the same sequence are still converted.

Is the input case-sensitive?

No. Inputs are normalized to uppercase automatically before conversion.

Can I convert three-letter codes back to one-letter codes?

Yes. Select "Three-letter" as the input format and "One-letter" as the output format.

Are non-standard or modified amino acids supported?

No. Only the 20 canonical amino acids defined in the standard genetic code are included.

Amino Acid Converter

Convert amino acid sequences between one-letter codes, three-letter abbreviations, and full names.

Input Sequence

Input Format

Sequence

Output Format

Output Separator

Load Sample

Converted Output

Enter a sequence and click Convert

One-letter	Three-letter	Full Name

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Summary

A client-side tool to convert protein sequences between the three standard amino acid notation formats: single-letter codes (e.g. A), three-letter abbreviations (e.g. Ala), and full names (e.g. Alanine). Covers all 20 standard amino acids with graceful handling of unknown characters.

How it works

Paste or type your amino acid sequence into the input box.
Select the input format (one-letter, three-letter, or full name).
Choose your target output format.
The converted sequence appears instantly and any unknown characters are flagged. All processing runs in your browser with no data sent to a server.

Use cases

Convert a one-letter protein sequence to three-letter abbreviations for publications.
Expand an abbreviated sequence to full amino acid names for teaching materials.
Quickly look up the full name of an unknown amino acid code.
Verify sequence integrity by cross-checking between notation formats.

Frequently Asked Questions

Last updated: 2026-09-30 · Reviewed by Nham Vu