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268+ 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 category below.
Total tools26810.8K total uses
Categories13Active categories
Most usedJSON Formatter4.1K uses
Recently addedExperiment RandomizerNewest tool
Half-Life Calculator
Calculate radioactive decay with half-life — remaining amount, elapsed time, or half-life from N = N₀(½)^(t/t½). Free, instant, browser-based.
Used 0 times•Updated never
Chemical Name Generator
Convert chemical formulas to names and names to formulas — ionic compounds, acids, hydrates, and common molecules. Free, instant, browser-based.
Used 0 times•Updated never
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
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
Restriction Enzyme Finder
Find restriction enzyme cut sites in DNA — EcoRI, BamHI, HindIII, and 30+ common enzymes with cut positions. Free, instant, 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
Blood Type Inheritance Calculator
Predict child blood types from parent ABO and Rh types — Punnett squares, probabilities, and combined outcomes like A+ or O−. Free, instant, browser-based.
Used 0 times•Updated never