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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
Oxidation Number Calculator
Find oxidation numbers in chemical formulas using standard rules — H2SO4, KMnO4, NH3, and polyatomic ions. Free, instant, browser-based.
Used 0 times•Updated never
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