Free online calculators and converters for everyday life!
Work out loan payments, solve math problems, convert units, and plan home projects. Find practical tools for finance, health, science, and the calculations that come up every day.
Search a Tool
01
Calculators and tools
Find calculators, converters, and practical tools to simplify everyday tasks, solve math problems, and plan projects.
02
Useful categories
Explore finance, health, math, science, construction, and more—all organized to help you find the right tool.
03
Free to use
Use free online calculators and converters for everyday questions, quick checks, and practical planning.
GCF Calculator
Find the greatest common factor of integers using factor lists, prime factorization or Euclid’s algorithm.
Retirement Calculator
Estimate retirement savings, contribution growth, inflation-adjusted value, income target, and potential gap with formulas and planning scenarios.
Max Heart Rate Calculator
Use this max heart rate calculator to estimate estimated maximum heart rate in beats per minute. Learn the inputs, formulas, examples, limitations, training t
RPM Calculator
Use our RPM Calculator to find engine RPM from speed or vehicle speed from RPM using overall gear ratio and tire diameter, plus wheel RPM and tire circumference.
Electricity Cost Calculator
Use our Electricity Cost Calculator to estimate appliance energy use, period cost, and annual electricity cost from watts, usage time, and price per kWh.
Elevation Grade Calculator
Use our Elevation Grade Calculator to find slope ratio, percent grade, angle of elevation, and 1 in N ratio from rise and run with mixed-unit support.
Atom Calculator
Use our Atom Calculator to find protons, neutrons, electrons, atomic number, mass number, and ionic charge quickly from standard atomic relationships.
Insulation Calculator
Estimate net insulation area and packages while checking R-value, cavity and product coverage separately.
Work Calculator
Calculate mechanical work using force, displacement, and the angle between them, with sign conventions, examples, and unit guidance.
Period Calculator
Predict your next period start/end, ovulation day, and fertile window from LMP and cycle length with this free period calculator.
Theoretical Yield Calculator
Theoretical Yield Calculator to find the maximum product yield from stoichiometry, limiting reagent, and molar relationships.
Fraction Calculator
Calculate fraction operations, simplify the result and understand common denominators and reciprocals.
Simple Loan Calculator
Use this simple loan calculator to calculate simple interest, total repayment, and periodic payment. Review inputs, formulas, examples, limitations, and FAQs.
Avogadro’s number calculator
Convert between moles and representative particles using the exact Avogadro constant, with examples for atoms, molecules, ions, and formula units.
Weight Gain Calculator
Use the Weight Gain Calculator to estimate a calorie surplus for weight gain. Review inputs, results, limitations, safety guidance, and FAQs.
Dog Age Calculator
Estimate a dog’s human-age equivalent and life stage using age and size, while understanding why the old seven-year rule is limited.
VO₂ Max Calculator
Use this vo₂ max calculator to estimate estimated aerobic capacity in milliliters of oxygen per kilogram per minute. Learn the inputs, formulas, examples, lim
Pressure Calculator
Calculate pressure, force, or area with common pressure-unit conversions and guidance about normal force, area, and gauge versus absolute pressure.
Framing Calculator
Free wall framing calculator: enter wall length/height, stud spacing (16″/24″ o.c.) & openings to get studs, plates, headers, sheathing and cost. Metric/imperial with waste %, steps & PDF.
Winning Percentage Calculator
Use this winning percentage calculator to estimate winning percentage, total games, and record comparisons. Learn the inputs, formulas, examples, limitations,
BMI Calculator (Body Mass Index)
Use the BMI Calculator to estimate adult body mass index. Review inputs, results, limitations, safety guidance, and FAQs.
Calories Burned Calculator
Use this calories burned calculator to estimate estimated exercise energy expenditure in calories. Learn the inputs, formulas, examples, limitations, training
Mixed Number Calculator
Calculate with mixed numbers by converting whole-and-fraction parts to improper fractions and simplifying.
CGPA to Percentage Calculator
Convert CGPA to percentage with proportional, legacy 9.5, or custom institutional methods, plus clear policy guidance and examples.
Rent vs Buy Calculator
Use this rent vs buy calculator to calculate estimated cumulative renting cost, ownership cost. Review key inputs, formulas, scenarios, limitations, and FAQs.
Compound Interest Calculator
Use this compound interest calculator to calculate future balance, total contributions, and compound growth. Review inputs, formulas, examples, limitations, a
Fraction to Decimal Calculator
Convert a fraction to terminating or repeating decimal form and understand when rounding is required.
Credit Card Interest Calculator
Estimate credit card interest, payoff time, and total repayment cost using balance, APR, payment amount, and compounding assumptions.
Percentile Calculator
Use our Percentile Calculator to find percentile values from a data set with nearest rank or linear interpolation. Supports raw numbers and value:count input.
Credit Card Payoff Calculator
Use this credit card payoff calculator to calculate estimated payoff date, number of payments. Review key inputs, formulas, scenarios, limitations, and FAQs.
Dose Calculator
Check dose arithmetic from an already verified prescription or label, including mg/kg, total mg and liquid volume conversions.
Stair Calculator
Estimate uniform risers, tread count, total run, angle and stringer length for a straight stair concept.
Force Calculator
Use our Force Calculator to find force from mass and acceleration with F = ma. Get instant results in newtons, kilonewtons, and pounds-force.
CAGR (Compound Annual Growth Rate) Calculator
Use this cagr (compound annual growth rate) calculator to calculate compound annual growth rate and annualized growth factor. Review inputs, formulas, example
Shannon Diversity Index Calculator
Calculate Shannon diversity H′, species richness, total abundance and evenness from species counts using ln, log10 or log2.
Fraction to Percentage Calculator
Convert fractions to percentages and percentages to simplified fractions. Enter numerator, denominator, or percent to get quick live results.
Concrete Calculator
Estimate concrete volume in cubic yards, feet, and meters, plus 40, 60, or 80 lb bags for slabs, pads, and rectangular pours with waste.
Conception Date Calculator
Use our Conception Date Calculator to estimate conception date, due date, ovulation day, fertile window, and pregnancy progress from due date or LMP.
Investment Calculator
Use this investment calculator to calculate projected future value, total contributions. Review key inputs, formulas, scenarios, limitations, and FAQs.
ml to Grams Converter
Convert mL to grams using ingredient density. Learn the formula, see a practical example, improve kitchen measuring accuracy, and review six helpful FAQs.
Exponent Calculator
Exponent Calculator helps you solve powers, positive and negative exponents, and exponential values quickly with clear, accurate results.
Average Percentage Calculator
Average percentage calculator to find simple or weighted averages of multiple percentages with quick, accurate results.
Target Heart Rate Calculator
Use this target heart rate calculator to estimate estimated lower and upper target heart rates. Learn the inputs, formulas, examples, limitations, training ti
BTU Calculator
Estimate a preliminary room heating or cooling load from volume, temperature difference and major adjustments.
Percentage Calculator
Percentage calculator for percent of a number, what percent one value is of another, and finding the whole from a percent.
Final Grade Calculator
Find the final exam score needed to reach a target grade or estimate the course result from an expected exam score.
Grams To Ounces Calculator
Use our Grams to Ounces Calculator to convert grams to ounces, ounces to grams, kilograms, milligrams, and troy ounces.
Free AVIF Image Converter
Easily convert AVIF images to JPG, PNG, or WebP formats with our user-friendly tool. Fast, efficient, and free for all your image conversion needs.
Dividend Calculator
Use this dividend calculator to calculate periodic and annual dividend income, yield, and projected reinvestment growth. Review inputs, formulas, examples, li
Margin Calculator
Use this margin calculator to calculate gross profit, margin percentage, markup percentage, and missing price variable. Review inputs, formulas, examples, lim
Nm to ft-lbs Converter
Use our Nm to ft-lbs Converter to convert newton-meters, foot-pounds, inch-pounds, kgf·cm, kgf·m, and other torque units.
Attendance Percentage Calculator
Calculate current attendance, missed classes, classes needed to reach a target, and how many future classes you may be able to miss.
Grams to Cups Converter
Convert grams to cups by ingredient. Learn why density and packing matter, follow the formula and example, and get practical baking tips plus six FAQs.
Z-test Calculator
Use our Z-Test Calculator to compute z statistic, p-value, standard error, and critical z for one-sample or two-sample mean tests when sigma is known.
IQR (Interquartile Range) Calculator
Use our IQR Calculator(Interquartile Range) to find Q1, Q3, median, and interquartile range from a data set. Supports raw numbers, value:count input, and two quartile methods.
Confidence Interval Calculator
Use our Confidence Interval Calculator to find confidence intervals for a mean or proportion with standard error, critical value, margin of error, and lower and upper bounds.
Semester Grade Calculator
Calculate a credit-weighted semester grade from course percentages and credits, then compare the result with an optional target.
Wavelength → Energy Calculator
Use our Wavelength to Energy Calculator to find photon energy from wavelength in joules, eV, and kJ/mol using E = hc / λ with vacuum or custom wave speed.
Mean Median Mode Calculator
Use our Mean Median Mode Calculator to find the average, median, and mode from any data set. Supports raw numbers, value:count input, and sorted preview.
Face Shape Calculator
Use our Face Shape Calculator to estimate your likely face shape from forehead, cheekbone, jawline, and face length measurements plus chin shape.
Waist-to-Height & Waist-to-Hip Ratio Calculator
Use the Waist-to-Height & Waist-to-Hip Ratio Calculator to estimate waist-to-height and waist-to-hip ratios. Learn inputs, limits, and FAQs.
FFMI Calculator (Fat-Free Mass Index)
Use the FFMI Calculator to estimate fat-free mass index. Review inputs, results, limitations, safety guidance, and FAQs.
Protein Calculator
Estimate a daily protein range from body weight, activity and goal for general nutrition planning.
Proportion Calculator
Solve a missing value in equivalent ratios and verify the result using equal cross products.
Median Calculator
Use our Median Calculator to find the middle value of any data set. Supports raw numbers, value:count input, sorted preview, and instant live results.
Square Footage Calculator
Square Footage Calculator helps you measure room area, total square feet, and material cost quickly with accurate results.
Area Calculator
Calculate the area of common two-dimensional shapes using dimensions in compatible units.
Image Converter Pro
Convert images among supported formats while managing quality, transparency, dimensions, metadata, file size, and browser compatibility.
Creatinine Clearance Calculator
Estimate creatinine clearance with the Cockcroft-Gault equation and review the assumptions, units and limitations behind the result.
Add Time Calculator
Use our Add Time Calculator to add hours, minutes, seconds, days, weeks, months, and years, then convert the total into your preferred time format.
Kinetic Energy Calculator
Calculate translational kinetic energy from mass and velocity, rearrange the formula, convert units, and explore the squared effect of speed.
Heart Rate Zone Calculator
Use this heart rate zone calculator to estimate estimated heart-rate training zones in beats per minute. Learn the inputs, formulas, examples, limitations, tr
SLEEP CALCULATOR
Plan a bedtime or wake-up time using target sleep duration and estimated cycles, with realistic guidance about sleep latency and individual needs.
Density Calculator
Calculate density, mass, or volume with unit conversion, worked examples, and clear guidance about temperature, mixtures, and measurement precision.
mmol/L to mg/dL Calculator
Use the mmol/L to mg/dL Calculator to estimate glucose unit conversions. Review inputs, results, limitations, safety guidance, and FAQs.
Margin & VAT Calculator
Use this margin & vat calculator to calculate net selling price, gross profit, tax amount, and final price. Review inputs, formulas, examples, limitations, an
Child BMI Calculator
Calculate BMI and estimate BMI-for-age percentile for a child or teen, with guidance on measurement and interpretation.
Sand Calculator
Use our Sand Calculator to estimate sand area, volume, weight, and optional total cost from length, width, depth, density, and price.
Beam Deflection Calculator
Estimate elastic beam deflection for common cantilever and simply supported cases using span, load, elastic modulus, and second moment of area.
Percentage of a Percentage Calculator
Percentage of a percentage calculator to find cumulative percentage and final value from two related percentage changes.
Stock Calculator
Use this stock calculator to calculate cost basis, proceeds, gain or loss, and percentage return. Review inputs, formulas, examples, limitations, and FAQs.
Air Conditioner Size Calculator
Estimate a room air conditioner’s preliminary BTU and tonnage range from dimensions and major load factors.
Baby Growth Percentile Calculator
Estimate an infant growth percentile for weight, length or head circumference and learn how to interpret the trend.
Ideal Weight Calculator
Use the Ideal Weight Calculator to estimate formula-based ideal body weight. Review inputs, results, limitations, safety guidance, and FAQs.
Percentage to CGPA Calculator
Convert percentage to CGPA using proportional, legacy 9.5, or custom institutional methods, with scale checks and policy guidance.
Acceleration Calculator
Calculate average acceleration from initial velocity, final velocity, and elapsed time while keeping direction, signs, and units consistent.
Mortgage Interest Calculator
Use this mortgage interest calculator to calculate estimated interest by period, total interest. Review key inputs, formulas, scenarios, limitations, and.
Slope Calculator
Use our Slope Calculator to find slope, angle, percent grade, line equation, y-intercept, rise/run, and distance using two points or other methods.
Desk Height Calculator
Use our Desk Height Calculator to estimate ergonomic chair height, desk height, and monitor height for sitting or standing work.
Variance Calculator
Use our Variance Calculator to find sample or population variance from a data set. Get mean, variance, standard deviation, SSE, range, and sorted values fast.
Basic Calculator
Perform everyday arithmetic with decimals, signs, parentheses and common percentage operations.
Lean Body Mass Calculator
Use the Lean Body Mass Calculator to estimate lean body mass. Review inputs, results, limitations, safety guidance, and FAQs.
mcg to IU Converter
Convert between micrograms and international units using the correct vitamin and chemical form, with label-reading and safety guidance.
Ratio Calculator
Simplify, scale and compare ratios or divide a quantity into proportional parts.
Board Foot Calculator
Calculate board feet from lumber thickness, width, length, and quantity. Learn the formula, compare prices, and estimate waste for a woodworking project.
Words per Minute Calculator
Use our Words Per Minute Calculator to estimate speaking time and reading time from word count, WPM speed, and result unit.
Work and Power Calculator
Calculate mechanical work and average power from force, displacement, angle, and elapsed time, with clear joule and watt interpretation.
t-test Calculator
Use our T-Test Calculator to compute t statistic, p-value, confidence interval, and conclusion for one-sample, Welch, pooled, or paired t-tests.
Percent Yield Calculator
Use our Percent Yield Calculator to calculate chemistry percent yield from actual yield and theoretical yield in mg, g, or kg.
Mortgage Calculator with Taxes and Insurance
Use this mortgage calculator with taxes and insurance to calculate estimated total monthly housing payment and component breakdown. Review key inputs,.