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.
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Calculators and tools
Find calculators, converters, and practical tools to simplify everyday tasks, solve math problems, and plan projects.
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Useful categories
Explore finance, health, math, science, construction, and more—all organized to help you find the right tool.
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Free to use
Use free online calculators and converters for everyday questions, quick checks, and practical planning.
GPA calculator
Calculate semester GPA and estimate cumulative GPA from course grade points and credit hours, with clear formulas and policy guidance.
Macro Calculator
Estimate daily calories and divide them into protein, carbohydrate and fat targets for general planning.
p-value Calculator
Use our P-value Calculator to calculate one-tailed or two-tailed p-values for Z, t, chi-square, and F test statistics.
CGPA Calculator
Calculate cumulative CGPA from semester GPA and credit hours with a credit-weighted formula, worked example, and policy checks.
Standard Deviation Calculator
Use our Standard Deviation Calculator to find sample or population standard deviation from a data set. Get variance, mean, range, and sorted values fast.
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.
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 Price Comparison Calculator
Use our Weight Price Comparison Calculator to compare two products by price per gram, kilogram, pound, or ounce and find the better value.
Debt-to-Income Ratio Calculator
Use this debt-to-income ratio calculator to calculate debt-to-income percentage and a clear breakdown of included debts. Review key inputs, formulas,.
Cubic Feet Calculator
Use our Cubic Feet Calculator to find volume from length, width, and height, with conversions to m³, yd³, in³, liters, and gallons.
Acceleration Calculator
Calculate average acceleration from initial velocity, final velocity, and elapsed time while keeping direction, signs, and units consistent.
APY Calculator
Use this apy calculator to calculate effective annual percentage yield and one-year growth factor. Review inputs, formulas, examples, limitations, and FAQs.
Square Root Calculator
Use our Square Root Calculator to find the principal square root of a number or reverse-calculate x from a square root value.
ABSI (A Body Shape Index) Calculator
Use the ABSI Calculator to estimate A Body Shape Index. Review inputs, results, limitations, safety guidance, and FAQs.
Circumference Calculator
Use our Circumference Calculator to find circle radius, diameter, circumference, and area from any one known value with unit conversions.
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.
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.
PayPal Fee Calculator
Estimate transaction fees, net receipts, or a gross request amount using the current percentage and fixed fee for your transaction type.
Volume Calculator
Calculate the volume of common three-dimensional solids using measurements in compatible units.
Hamster Age Calculator
Use our Hamster Age Calculator to convert hamster years to human years or human age back to hamster age with chart-based interpolation.
Ideal Gas Law Calculator
Use our Ideal Gas Law Calculator to solve pressure, volume, moles, or temperature with PV = nRT. Supports SI and L·atm gas constants with unit conversion.
Speed Calculator
Use our Speed Calculator to find average speed from distance and time in m/s, km/h, mph, ft/s, or knots with step-by-step results.
Stock Calculator
Use this stock calculator to calculate cost basis, proceeds, gain or loss, and percentage return. Review inputs, formulas, examples, limitations, and FAQs.
Alcohol Dilution Calculator
Use the Alcohol Dilution Calculator to estimate final volume and diluent needed from starting and target ABV, with formula, examples, safety notes, and FAQs.
t-statistic Calculator
Use our t-Statistic Calculator to compute the t value, degrees of freedom, and standard error for one-sample, two-sample, Welch, pooled, or paired t-tests.
Pre & Post-Money Valuation Calculator
Use this pre & post-money valuation calculator to calculate post-money valuation and implied investor or founder ownership. Review inputs, formulas, examples,
Flooring Calculator
Calculate floor area, cutting waste and the number of complete flooring boxes or rolls to purchase.
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.
Bench Press 1RM Calculator
Use this bench press 1rm calculator to estimate estimated one-repetition maximum and optional training percentages. Learn the inputs, formulas, examples, limi
Cholesterol Units Converter
Convert cholesterol and triglyceride measurements between mg/dL and mmol/L with analyte-specific factors and careful result interpretation.
Blood Pressure Category Calculator
Classify an adult blood pressure reading and calculate pulse pressure and estimated mean arterial pressure, with measurement guidance.
BC to AD Year Difference Calculator
Use our BC to AD Year Difference Calculator to find the years between BC/BCE and AD/CE dates using the no-year-0 formula.
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.
Creatinine Clearance Calculator
Estimate creatinine clearance with the Cockcroft-Gault equation and review the assumptions, units and limitations behind the result.
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.
Stride Length Calculator
Use this stride length calculator to estimate average stride or step length in chosen units. Learn the inputs, formulas, examples, limitations, training tips,
ROI (Return on Investment) Calculator
Use this roi (return on investment) calculator to calculate net gain, return on investment percentage, and optional annualized comparison. Review inputs, form
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.
Log Calculator (Logarithm)
Log Calculator helps you solve logarithms with base 10, base e, base 2, or any custom base. Get fast and accurate log results online.
Retirement Calculator
Estimate retirement savings, contribution growth, inflation-adjusted value, income target, and potential gap with formulas and planning scenarios.
Cycling Calorie Calculator
Estimate calories burned while cycling from body weight, duration, pace and ride conditions, with guidance for interpreting MET-based results.
Percent Yield Calculator
Use our Percent Yield Calculator to calculate chemistry percent yield from actual yield and theoretical yield in mg, g, or kg.
Basic Calculator
Perform everyday arithmetic with decimals, signs, parentheses and common percentage operations.
INR Calculator
Use our INR Calculator to solve for INR, patient PT, control PT, or ISI with the standard PT/INR formula. Fast educational estimate online.
Final Grade Calculator
Find the final exam score needed to reach a target grade or estimate the course result from an expected exam score.
Theoretical Yield Calculator
Theoretical Yield Calculator to find the maximum product yield from stoichiometry, limiting reagent, and molar relationships.
Area Calculator
Calculate the area of common two-dimensional shapes using dimensions in compatible units.
Debt Payoff Calculator
Use this debt payoff calculator to calculate estimated payoff date, total interest. Review key inputs, formulas, scenarios, limitations, and FAQs.
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
Calorie Calculator
Use the Calorie Calculator to estimate daily calorie needs. Review inputs, results, limitations, safety guidance, and FAQs.
CGPA to Percentage Calculator
Convert CGPA to percentage with proportional, legacy 9.5, or custom institutional methods, plus clear policy guidance and examples.
Pixels to Inches converter
Pixels to Inches Converter helps you quickly convert px to inches using PPI or DPI. Get accurate results for print, design, and screen sizing.
Water Intake Calculator
Estimate a general daily hydration target from body weight, activity and climate, with practical guidance on interpreting the result.
Fraction to Decimal Calculator
Convert a fraction to terminating or repeating decimal form and understand when rounding is required.
Savings Goal Calculator
Use this savings goal calculator to calculate required periodic saving, projected growth. Review key inputs, formulas, scenarios, limitations, and FAQs.
Image Color Picker
Pick an exact pixel from an uploaded image and copy its color in HEX, RGB, HSL, HSV, CMYK or OKLCH formats.
Circle Skirt Calculator
Circle Skirt Calculator to find waist radius, hem measurements, and fabric requirements for full, half, or quarter skirts.
Salary to Hourly Calculator
Use this salary to hourly calculator to calculate equivalent monthly, weekly, daily, and hourly gross pay. Review inputs, formulas, examples, limitations, and
Price Elasticity of Demand Calculator
Use this price elasticity of demand calculator to calculate percentage changes, elasticity coefficient, and basic elasticity classification. Review inputs, fo
Personal Loan Calculator
Use this personal loan calculator to calculate estimated payment, total interest. Review key inputs, formulas, scenarios, limitations, and FAQs.
Salary calculator
Convert gross salary among annual, monthly, weekly, daily, and hourly amounts using your actual work schedule and paid-time assumptions.
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.
Child Height Percentile Calculator
Use the Child Height Percentile Calculator to estimate a child height percentile. Review inputs, results, limitations, safety guidance, and FAQs.
One Rep Max Calculator
Estimate your one-repetition maximum from a completed submaximal set and translate it into practical training percentages.
Work Calculator
Calculate mechanical work using force, displacement, and the angle between them, with sign conventions, examples, and unit guidance.
Room Size Calculator
Calculate a rectangular room’s floor, ceiling, wall area, perimeter and volume from inside dimensions.
Marks Percentage Calculator
Calculate percentage from obtained and total marks, see marks lost, and compare your score with an optional passing or target percentage.
Cat Age Calculator
Use this Cat Age Calculator to estimate your cat’s age in human years using the common 15 / 24 / +4 cat age chart. Includes formula, examples, life stages, and care notes.
Mixed Number Calculator
Calculate with mixed numbers by converting whole-and-fraction parts to improper fractions and simplifying.
Gravitational Force Calculator
Use our Gravitational Force Calculator to find the force between two masses with Newton’s law of gravitation. Get results in newtons, lbf, and acceleration on each mass.
Paint Calculator
Estimate wall-paint quantity from room dimensions, openings, coats, coverage and a practical allowance.
Exponent Calculator
Exponent Calculator helps you solve powers, positive and negative exponents, and exponential values quickly with clear, accurate results.
Probability Calculator
Calculate event probabilities, complements, unions and intersections while checking independence 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.
Student Loan Calculator
Use this student loan calculator to calculate estimated payment, payoff time. Review key inputs, formulas, scenarios, limitations, and FAQs.
Calorie Deficit Calculator
Use our Calorie Deficit Calculator to estimate BMR, maintenance calories, TDEE, calorie deficit, target calories, and weekly weight-change estimate.
Z-score Calculator
Use our Z-Score Calculator to standardize a value or sample mean, convert percentile to z, convert z to percentile, and view left-tail and right-tail probabilities.
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.
Atom Calculator
Use our Atom Calculator to find protons, neutrons, electrons, atomic number, mass number, and ionic charge quickly from standard atomic relationships.
Taper Calculator
Use our Taper Calculator to find taper per length, taper ratio, half-angle, and included angle from large diameter, small diameter, and taper length.
Pipe Volume Calculator
Calculate pipe volume from inner diameter and length. Get capacity in m³, liters, and US gallons (plus per-length). Supports mm/in and ft/m. Shows formula and steps; instant results & PDF.
Pace Calculator
Use this pace calculator to estimate pace per mile or kilometer, average speed, and projected times. Learn the inputs, formulas, examples, limitations, traini
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.
Mortgage Interest Calculator
Use this mortgage interest calculator to calculate estimated interest by period, total interest. Review key inputs, formulas, scenarios, limitations, and.
Length Converter
Use our Length Converter to convert metric, imperial, US, nautical, survey, and astronomy units including mm, cm, m, km, in, ft, yd, mi, nmi, au, ly, and pc.
Helium Balloons Calculator
Use our Helium Balloons Calculator to estimate lift per balloon, total helium volume, and how many helium balloons you need to lift a given weight.
Plant Spacing Calculator
Use our Plant Spacing Calculator to estimate how many plants fit in a garden bed, crop row, or square-foot layout from area and spacing.
Age Difference Calculator
Use our Age Difference Calculator to find the exact age gap between two dates of birth in years, months, days, total months, total days, and approximate years.
Dilution Ratio Calculator
Use our Dilution Ratio Calculator to calculate concentrate, water, final volume, or dilution ratio for water-to-concentrate mixes.
pH Calculator
Free pH calculator that syncs [H+], [OH−], pOH, concentration, and mass/volume. Supports strong/weak acids and bases, unit options, steps, and PDF.
Tile Calculator
Estimate tiles, edge cuts and full boxes using the project size, tile dimensions, grout gap and waste allowance.
Hiking Calorie Calculator
Estimate calories burned on a hike using weight, moving time, distance, elevation, terrain and backpack load.
Percentage to CGPA Calculator
Convert percentage to CGPA using proportional, legacy 9.5, or custom institutional methods, with scale checks and policy guidance.
WebP Converter
Convert JPG, PNG, WebP, or SVG images to WebP in your browser. Adjust quality, resize by max width or height, preview, and download.
Inflation Calculator
Compare purchasing power between years using a selected price index and understand cumulative inflation, base periods, regional scope, and data revisions.
Fence Calculator
Estimate fence panels, posts and rails from route length, gates, section spacing and closed-perimeter conditions.
Plastic Footprint Calculator
Estimate annual household plastic use in kilograms and pounds from common disposable items, frequencies and model item weights.
Tank Volume Calculator
Tank Volume Calculator helps you find tank capacity in gallons, liters, and cubic units with fast, accurate results.
Dihybrid Cross (Punnett Square) Calculator
Use the Dihybrid Cross Calculator to generate a 4×4 Punnett square, gametes, genotypes, phenotypes, and probabilities for two traits.
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