Gratis online tools
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 1 times•Updated 56 minutes ago
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 1 times•Updated 3 minutes ago
Genetic Probability Calculator
Calculate offspring genotype and phenotype probabilities from Punnett squares — monohybrid and dihybrid crosses with instant results. Free, browser-based.
Used 1 times•Updated 5 minutes ago
Derivative Calculator
Compute symbolic derivatives of functions with step-by-step rules. Supports polynomials, trig, ln, exp, and more.
Used 1 times•Updated 40 minutes ago
Integral Calculator
Compute symbolic indefinite integrals with step-by-step rules. Supports polynomials, trig, exp, and 1/x.
Used 1 times•Updated 48 minutes ago
Matrix Calculator
Add, subtract, multiply, transpose, invert, and find determinants of matrices up to 6×6.
Used 1 times•Updated 54 minutes ago
LCM Calculator
Find the least common multiple (LCM) and GCD of two or more positive integers with prime-factor and step-by-step GCD methods.
Used 1 times•Updated 46 minutes ago
Standard Deviation Calculator
Calculate sample and population standard deviation and variance from any data set with squared-deviation steps.
Used 1 times•Updated 42 minutes ago
Solar Angle Calculator
Calculate solar elevation, azimuth, and noon altitude from latitude, date, and time. Find shadow length from sun angle and object height. Free, browser-based.
Used 1 times•Updated 43 minutes ago
Moon Phase Calculator
Find the moon phase for any date — new moon, full moon, quarters, and crescents. Shows illumination %, moon age, and days to next new or full moon. Free, browser-based.
Used 1 times•Updated 7 minutes ago
Astronomical Unit Converter
Convert astronomical units (AU) to light-years, parsecs, kilometers, meters, and miles. Enter any distance and get instant conversions with formulas. Free, browser-based.
Used 1 times•Updated 42 minutes ago
Richter Scale Calculator
Calculate Richter magnitude from seismograph amplitude and distance, explore effects and energy for any ML value, or compare two magnitudes. Free, browser-based.
Used 1 times•Updated 40 minutes ago