Sequencing and bioinformatics calculators

Seqrun is a hub of fast, single-purpose calculators for the lab and the command line. Pick a tool, type your numbers, and get the answer — every calculation runs entirely in your browser.

Browse all 26 calculators Read the explainers

Popular calculators

• Sequencing coverage calculator Work out mean depth of coverage from genome size, read length and read count — or the number of reads you need to hit a target depth.
• ng/µL ⇄ nM converter Convert dsDNA concentration between mass units (ng/µL) and molarity (nM) for a fragment of a given length. Essential for library pooling and loading.
• Primer melting temperature (Wallace rule) Estimate the melting temperature of a short DNA oligo with the Wallace "2 + 4" rule, plus GC content, length and reverse complement.
• GC content calculator Calculate the percentage of G and C bases in a DNA sequence, with base counts. Handy for primer design and assessing sequence composition.
• Phred quality score converter Convert between a Phred quality score (Q) and base-call accuracy / error probability, both directions. Q30 means 99.9% accuracy.
• FASTQ quality check Drop in a .fastq or .fastq.gz file to see read count, read-length distribution, GC content and per-base quality — computed entirely in your browser.

Browse by category

• Sequencing 3
• Library prep 7
• PCR & primers 4
• Sequence utilities 6
• Quality scores 1
• Quality control 3
• Planning 2

How it works

Every calculator is a single page: the tool above the fold, and a plain-language explainer below it — the formula, a worked example, and when to use it. The maths is open and runs as JavaScript in your browser, with no accounts and no uploads. For file-based tools like the FASTQ quality check, your file is read locally and never leaves your computer.

New to a topic? The learn section explains the concepts behind the tools, each paired with the calculator that puts it to work.