Understand the relationship
The reasoning behind the result
Length follows the retained record
L = Σ symbol counts
Whitespace and one FASTA header are removed, while every supported sequence symbol is retained.
Length is not inferred from coordinates, coverage or a reference assembly.
Ambiguity codes describe sets
GCmin ≤ true GC count ≤ GCmax
R, Y, N and the other IUPAC codes name possible-base sets. They do not imply equal probabilities.
The interval follows set membership and remains valid without inventing a distribution.
DNA and RNA alphabets stay explicit
DNA uses thymine and RNA uses uracil. Selecting the polymer changes validation and the AT/U label.
A mixed alphabet is rejected rather than normalized silently.
Composition is descriptive
Base composition alone does not establish coding potential, structure, amplification performance or biological function.
Assembly gaps, quality scores and per-position likelihoods require richer records than a sequence string.
Follow the numbers
Bound GC content in an ambiguous DNA record
- The DNA record ACGTRYSWNN contains ten retained symbols.
- A, C, G and T contribute exact identities; six positions retain IUPAC sets.
- C, G and S are certainly G/C and set the minimum.
- C, G, R, Y, S and both N positions can be G/C and set the maximum.
- The result reports both percentages instead of an arbitrary midpoint.
The interval is a possible-composition bound, not a confidence interval or expected value.
Quick guide
How to use this calculator
- Declare DNA or RNA before entering the record.
- Review exact symbol counts and the retained ambiguity count.
- Use the GC interval whenever ambiguity prevents one exact percentage.
Calculation method
Calculation and interpretation
Replace isolated length and composition counters with one inspectable sequence ledger that preserves uncertainty.
Length is the retained symbol count. GC minimum counts symbols whose every possible base is G/C; GC maximum counts symbols with at least one G/C possibility.
Worked example
Bound GC content in an ambiguous DNA record
The interval is a possible-composition bound, not a confidence interval or expected value.
Length is the retained symbol count. GC minimum counts symbols whose every possible base is G/C; GC maximum counts symbols with at least one G/C possibility.
Supported inputs
Precision and limits
One sequence record
One raw sequence or one FASTA record is accepted; alignments and multiple records are excluded.
No ambiguity probabilities
IUPAC sets receive no assumed frequency distribution or quality weighting.
No assembly interpretation
Coordinates, gaps, strand placement and reference mapping are not inferred.
No functional inference
Composition does not identify genes, motifs, expression or structure.
Numerical support
Complete statistics are retained for up to 200,000 nucleotide symbols.
Continue calculating
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