Calculator
Example Data Table
| Sample Name | Sequence | Expected GC% | Length |
|---|---|---|---|
| Sample Alpha | ATGCGCGTTAACG | 53.8462 | 13 |
| Sample Beta | AAAAATTTTT | 0.0000 | 10 |
| Sample Gamma | GGGCCCGGCC | 100.0000 | 10 |
Formula Used
GC% (GC content) measures the fraction of G and C bases in a sequence.
- GC% = (G + C) / Denominator × 100
- AT% = (A + T) / Denominator × 100
- Denominator = A + T + G + C (default)
- If enabled, Denominator becomes A + T + G + C + N + Other.
Ambiguous bases include N and any non-ACGT letters after cleaning.
How to Use This Calculator
- Paste your sequence in the input box (raw or FASTA).
- Choose Auto-detect, Raw, or FASTA mode.
- Enable optional settings like U to T conversion.
- Click Submit to see results under the header.
- Download CSV or PDF to store and share outputs.
FAQs
1) What does GC% tell me?
GC% indicates how much of your sequence is G and C. Higher GC often correlates with greater duplex stability and different organismal or genomic regions.
2) Can I paste multiple sequences at once?
Yes. Use FASTA format with headers starting using the greater-than symbol. Each sequence is calculated separately, plus an overall combined summary.
3) How are spaces, numbers, and line breaks handled?
They are removed during cleaning. Only letters remain, then the calculator counts A, T, G, C, N, and other letters as ambiguous.
4) What happens with ambiguous bases like N or R?
They are reported as ambiguous. By default, GC% uses only A, T, G, and C in the denominator. You can include ambiguous bases if needed.
5) Does it support RNA sequences?
It can. Enable “Convert U to T” to treat U as T, then compute GC% using the converted sequence.
6) What is the sliding window option for?
Sliding window GC% shows local GC variation across a sequence. It’s useful for spotting GC-rich islands or low-complexity segments.
7) Why might my GC% differ from another tool?
Differences usually come from cleaning rules and denominators. Confirm whether ambiguous bases are excluded and whether case, U bases, or non-letters are handled similarly.
8) Is my sequence stored anywhere?
No. The calculator processes your input within the page request and shows results immediately. Downloads are generated on demand from the same computed values.