Math Tools

Calculate your exact chronological age in years, months, weeks, days, hours, and minutes from your date of birth. See life milestones, zodiac signs, and next birthday countdown. Free online age calculator - no signup required.

Calculate date differences online for free with our date difference calculator. Instantly find days, weeks, months, and years between any two dates. Accurate, fast, and no signup required.

Add or subtract days, weeks, months, years, hours, minutes, and seconds from any date. Support for weekdays/business days calculations. Free online date calculator - no signup required.

Calculate exact days, weeks, months, or years until a future event or since a past milestone. Save custom events to your dashboard. Free online date counter - no signup required.

Count weekdays (Mon-Fri) between any two dates with optional public holiday exclusion for US, UK, Canada, Australia, and India. Get per-day breakdown and net working-day count. Free online weekday counter - no signup required.

Live ticking countdown to any future date and time with days, hours, minutes, and seconds. Save unlimited events to your personal dashboard. Free online countdown timer - no signup required.

Calculate your financial independence number from annual expenses and safe withdrawal rate. See years to FIRE, Lean/Regular/Fat FIRE variants, and year-by-year portfolio projection. Free online FIRE calculator - no signup required.

Calculate net present value from discount rate and cash flow series. See present value of each period, cumulative NPV, payback period, and accept/reject recommendation. Free online NPV calculator - no signup required.

Calculate fixed deposit maturity amount, total interest earned, and effective annual rate with quarterly, monthly, or annual compounding. Year-by-year growth table included. Free online FD calculator - no signup required.

Balance chemical equations by entering reactants and products in standard notation - uses Gaussian elimination for accurate integer coefficients. Free online chemical equation balancer.

Simulate AND, OR, NOT, NAND, NOR, XOR, XNOR, and BUFFER logic gates with real-time output, truth tables, and Boolean expressions - up to 8 gates simultaneously. Free online logic gate simulator.

Free resistor color code decoder online. Decode resistor color bands to resistance value and tolerance for 3, 4, 5, and 6-band resistors. Resistor color code decoder with encode mode - no signup required.

Calculate Total Daily Energy Expenditure from age, height, weight, and activity level using the Mifflin-St Jeor equation - get BMR, maintenance calories, goal targets, and macros. Free online TDEE calculator.

Calculate Basal Metabolic Rate using Mifflin-St Jeor and Harris-Benedict formulas with side-by-side comparison. Optionally add body fat % for Katch-McArdle. Includes TDEE reference table for all activity levels. Free online BMR calculator - no signup required.

Calculate calories burned from steps using MET values. Shows distance, walking duration, fat grams burned, and a step goal comparison table for 2,000-15,000 steps. Metric and imperial units. Free online steps to calories calculator - no signup required.

Estimate your 1RM using six formulas - Epley, Brzycki, Lander, Lombardi, Mayhew, and O'Conner. Formula comparison table and percentage-based training load table from 60-100% 1RM. Free online 1 rep max calculator - no signup required.

Calculate daily protein, carbs, and fat targets from your TDEE and goal - cut, bulk, or maintain. Supports 4 macro split presets (balanced, high protein, low carb, high carb) and custom splits. Free online macro calculator - no signup required.

Calculate running pace, finish time, or distance from any two known values. Supports km and miles with automatic split times for 5K, 10K, half marathon, and marathon. Free online running pace calculator - no signup required.

Predict a child's adult height from father and mother heights using the Mid-Parent (Tanner) formula with a 95% prediction range. Supports metric and imperial units. Free online child height predictor - no signup required.

Calculate Wilks coefficient, Wilks2 (2020), IPF GL Points, and DOTS Score from body weight and powerlifting total (squat + bench + deadlift). Level classification from Beginner to World Class. Free online Wilks score calculator - no signup required.

Calculate Total/HDL, LDL/HDL, Triglycerides/HDL, and Non-HDL cholesterol ratios with cardiovascular risk interpretation based on AHA/ACC guidelines. Supports mg/dL and mmol/L. Free online cholesterol ratio calculator - no signup required.

Calculate voltage, current, resistance, or power from any two known electrical values - supports all 6 input combinations and SI prefixes (kΩ, mA, μW). Free online Ohm's Law calculator.

Calculate total resistance for resistors in series, parallel, and mixed series-parallel combinations. Add unlimited resistors, supports SI prefixes (kΩ, MΩ, mΩ) and real-time results. Free online resistors in series and parallel calculator.

Solve for speed, distance, or time from any two known values - 6 speed units, 7 distance units, 5 time units, cross-unit conversions, and human-readable time output. Free online speed distance time calculator.

Calculate pendulum period from length and gravity, or find the required length for a target period. Supports 10 planetary gravity presets, 5 length units, frequency, angular frequency, and planet comparison table. Free online pendulum period calculator.

Calculate the gravitational force between any two masses using Newton's law of universal gravitation (F = G × m₁ × m₂ / r²). Supports kg, solar masses, Earth masses, AU, and light-years with scientific notation. Free online gravitational force calculator.

Calculate range, maximum height, time of flight, and impact velocity for any projectile - enter initial velocity, launch angle, and optional initial height. Live trajectory graph and full formula reference. Free online projectile motion calculator.

Solve any SUVAT kinematics problem - enter any 3 of the 5 variables (displacement, initial velocity, final velocity, acceleration, time) and the calculator solves for the rest using constant-acceleration equations. Free online kinematics calculator.

Solve the thin lens equation and mirror equation for image distance, object distance, or focal length. Supports converging/diverging lenses and concave/convex mirrors. Computes magnification and classifies images as real/virtual, upright/inverted. Free online optics calculator.

Calculate buoyant force from object volume and fluid density using Archimedes’ principle (F = ρVg). Includes fluid and gravity presets, plus float/sink analysis with object mass. Free online buoyancy calculator.

Calculate the molecular weight of any chemical formula using IUPAC 2021 atomic weights. Supports all 118 elements, parentheses, brackets, and hydrate notation - Free online molecular weight calculator.

Calculate the molar mass of any chemical formula using standard IUPAC 2021 atomic weights. Supports chemical subscripts, nested parentheses, square brackets, and hydrates. Free online molar mass calculator - no signup required.

Solve the dilution equation C1V1 = C2V2 for stock or diluted concentration or volume. Features a solute molecular weight converter, multi-unit selectors, and interactive beaker visuals. Free online dilution calculator.

Calculate molar concentration, mass, volume, or moles of solute instantly. Features a built-in chemical formula weight converter and multi-unit support. Free online molarity calculator.

Calculate the pH, pKa, or concentrations of a buffer solution using the Henderson-Hasselbalch equation. Supports acidic and basic buffer systems. Free online buffer pH calculator.

Solve stoichiometry problems from balanced chemical equations. Enter reactants and products to automatically balance the equation, then input any substance amount to compute the corresponding amounts for all other species. Free online stoichiometry calculator, no signup required.

Calculate the percent composition by mass of each element in a chemical compound. Enter any chemical formula to get element percentages, molecular weight, and step-by-step mathematical breakdown with an interactive donut chart. Free online percent composition calculator.

Calculate the empirical formula and molecular formula of a chemical compound from mass percentages or weights. Search standard atomic weights, solve ratios, and see step-by-step calculations. Free online empirical formula calculator.

Calculate the limiting reagent, theoretical yield, and percent yield of a chemical reaction. Input reactant amounts (in grams or moles), stoichiometric coefficients, and product parameters to find limiting/excess species and step-by-step conversions. Free online limiting reagent calculator.

Convert any date and time from one timezone to multiple timezones simultaneously with automatic DST handling - supports 80+ IANA timezones. Free online timezone converter.

Look up what any time zone abbreviation means - full name, UTC offset, DST status, and disambiguation notes for 90+ abbreviations across all regions. Free online time zone reference.

Calculate sunrise, sunset, solar noon, and day length for any date and location using the NOAA solar position algorithm - supports polar day and polar night. Free online day length calculator.

Generate customizable, interactive multiplication tables up to 30x30. Highlight even, odd, prime, or square numbers, customize multiples, practice mental math with Quiz Mode, and print clean layouts. Free online interactive multiplication table worksheets.

Analyze any positive integer up to 9,007,199,254,740,991. Check primality, perfect/abundant/deficient classification, Fibonacci or triangular numbers, happy number cycles, prime factors, and sorted divisors. Free online number properties explorer.

Generate a reference table of decimal numbers with their binary, octal, and hexadecimal equivalents. Customize range, adjust bit padding, search values, and export data. Free online base conversion table.

Convert between 20+ length and distance units - mm, cm, m, km, in, ft, yd, mi, nautical miles, light-years, parsecs, and more. Free online length distance converter - no signup required.

Convert between 20 power units - watts, kilowatts, megawatts, horsepower (mechanical, metric, electric), BTU/hr, ft·lbf/s, tons of refrigeration, dBm, and more. Free online power converter - no signup required.

Convert between 15 time units - milliseconds, seconds, minutes, hours, days, weeks, months, years, decades, centuries, and millennia. Free online time converter - no signup required.

Convert between 15 force units - newtons, kilonewtons, pound-force, kilogram-force, dyne, poundal, kip-force, ounce-force, and more. Free online force converter - no signup required.

Convert luminance and illuminance units - lux, foot-candle, phot, nox, nit, cd/m², foot-lambert, stilb, apostilb, lambert, and more. Free online luminance illuminance converter - no signup required.

Convert between US, UK/AU, EU/ISO, Japan ring sizes and diameter/circumference in mm. Includes a printable ring sizer and full reference chart. Free online ring size converter - no signup required.