Free Online Tools
184+ free online tools for PDF, images, SEO, developers, color, and productivity. Fast, browser-based, and private — no signup, no installs, no limits. Search above or browse by collection below.
Total tools18410.7K total uses
Categories11Active categories
Most usedJSON Formatter4.1K uses
Recently addedElectron Configuration GeneratorNewest tool
DNA to RNA Converter
Convert DNA to RNA — replace T with U on the coding strand, or transcribe from the template strand. FASTA support. Free, instant, browser-based.
Used 0 times•Updated never
RNA to Protein Translator
Translate RNA to protein with the standard genetic code — reading frames, AUG start, stop codons, and codon table. Free, instant, browser-based.
Used 0 times•Updated never
Codon Finder
Find codons in RNA or DNA — search AUG, stop codons, scan reading frames, and view codon frequencies. Free, instant, browser-based.
Used 0 times•Updated never
GC Content Calculator
Calculate GC content and base composition for DNA or RNA — percentages, counts, AT/GC ratio, and FASTA support. Free, instant, browser-based.
Used 0 times•Updated never
Melting Temperature Calculator
Calculate DNA primer melting temperature (Tm) — Wallace rule, salt-adjusted, and long-oligo formulas with adjustable Na⁺. Free, instant, browser-based.
Used 0 times•Updated never
Protein Molecular Weight Calculator
Calculate protein molecular weight from amino acid sequence — average mass in Da and kDa with composition breakdown. Free, instant, browser-based.
Used 0 times•Updated never
Genetic Probability Calculator
Calculate offspring genotype and phenotype probabilities from Punnett squares — monohybrid and dihybrid crosses with instant results. Free, browser-based.
Used 0 times•Updated never
Punnett Square Generator
Generate Punnett squares for monohybrid and dihybrid crosses with custom trait names, parent labels, and genotype or phenotype ratios. Free, instant, browser-based.
Used 0 times•Updated never
Population Growth Calculator
Calculate population growth with exponential and logistic models — solve for N, growth rate r, time, or N₀ with projections and doubling time. Free, browser-based.
Used 0 times•Updated never
Cell Division Calculator
Calculate cell count after binary fission — solve for N, N₀, divisions, generation time, or elapsed time with step-by-step growth table. Free, browser-based.
Used 0 times•Updated never
Heart Rate Zone Calculator
Calculate heart rate training zones with Karvonen or % max HR — 3 or 5 zones from age, resting HR, and max HR formulas. Free, instant, browser-based.
Used 0 times•Updated never
BMR Calculator
Calculate basal metabolic rate (BMR) with Mifflin-St Jeor, Harris-Benedict, or Katch-McArdle — compare formulas and TDEE estimates. Free, instant, browser-based.
Used 0 times•Updated never