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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
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 Reverse Complement
Get the reverse complement of a DNA or RNA sequence — A↔T/U, G↔C with GC content and FASTA support. 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
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
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