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.
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.
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.
Fraction Calculator
Calculate fraction operations, simplify the result and understand common denominators and reciprocals.
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.
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
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
Drywall Calculator
Estimate whole drywall sheets for walls and an optional ceiling using room dimensions, panel size and waste.
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.
Reading Time Calculator
Use our Reading Time Calculator to estimate how long it takes to read a book, daily pages read, and time needed to finish from pages and reading speed.
Creatinine Clearance Calculator
Estimate creatinine clearance with the Cockcroft-Gault equation and review the assumptions, units and limitations behind the result.
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.
Sand Calculator
Use our Sand Calculator to estimate sand area, volume, weight, and optional total cost from length, width, depth, density, and price.
Quadratic Formula Calculator
Solve a quadratic equation from coefficients a, b and c and interpret its discriminant and roots.
Rounding Calculator
Round numbers to a selected place or significant figures and distinguish common rounding methods.
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.
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.
Minutes to Hours Converter
Minutes to Hours Converter to instantly convert minutes into decimal hours or hours and minutes with clear results.
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.
Asphalt Calculator
Estimate compacted asphalt volume and tonnage from paving area, thickness, density and ordering allowance.
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.
Molarity Calculator
Use our Molarity Calculator to find moles, mass concentration, and molarity from solute mass, molar mass, and solution volume.
Winning Percentage Calculator
Use this winning percentage calculator to estimate winning percentage, total games, and record comparisons. Learn the inputs, formulas, examples, limitations,
Paver Calculator
Estimate whole pavers for a patio or walkway using actual dimensions, joint width, pattern and cutting waste.
Margin Calculator
Use this margin calculator to calculate gross profit, margin percentage, markup percentage, and missing price variable. Review inputs, formulas, examples, lim
BTU Calculator
Estimate a preliminary room heating or cooling load from volume, temperature difference and major adjustments.
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.
Interest Rate Calculator
Solve for interest rate, principal, balance, or time while distinguishing simple, compound, nominal, and effective rate assumptions.
Ohm’s Law Resistance Calculator
Use our Ohm’s Law Resistance Calculator to find resistance from voltage and current. Get instant results in Ω, kΩ, or MΩ plus power and conductance.
Fraction to Decimal Calculator
Convert a fraction to terminating or repeating decimal form and understand when rounding is required.
Balance Transfer Calculator
Compare a balance transfer’s fee, promotional period, payment plan, and post-promotion APR against keeping the current credit-card balance.
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.
Circumference Calculator
Use our Circumference Calculator to find circle radius, diameter, circumference, and area from any one known value with unit conversions.
Area Calculator
Calculate the area of common two-dimensional shapes using dimensions in compatible units.
Simple Loan Calculator
Use this simple loan calculator to calculate simple interest, total repayment, and periodic payment. Review inputs, formulas, examples, limitations, and FAQs.
Margin of Error Calculator
Use our Margin of Error Calculator to find margin of error for a mean or proportion from sample size, confidence level, and z value.
Decimal to Fraction Calculator
Convert terminating or repeating decimals to reduced fractions and mixed-number form.
Mulch Calculator
Calculate mulch volume and full bags from landscape-bed area and the finished depth you intend to maintain.
Punnett Square Calculator
Punnett Square Calculator predicts AA, Aa and aa genotype probabilities and dominant or recessive phenotypes for a simple one-gene genetic cross.
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.
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.
Inflation Calculator
Compare purchasing power between years using a selected price index and understand cumulative inflation, base periods, regional scope, and data revisions.
Ratio Calculator
Simplify, scale and compare ratios or divide a quantity into proportional parts.
Inches to Fraction Calculator
Inches to Fraction Calculator converts decimal inch values into usable fractions for construction, woodworking, machining, and daily measurements.
Probability Calculator
Calculate event probabilities, complements, unions and intersections while checking independence assumptions.
Potential Energy Calculator
Calculate near-Earth gravitational potential energy from mass, gravitational acceleration, and height relative to a chosen reference level.
Blood Pressure Category Calculator
Classify an adult blood pressure reading and calculate pulse pressure and estimated mean arterial pressure, with measurement guidance.
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.
Percentage of a Percentage Calculator
Percentage of a percentage calculator to find cumulative percentage and final value from two related percentage changes.
Basic Calculator
Perform everyday arithmetic with decimals, signs, parentheses and common percentage operations.
Fuel Cost Calculator
Fuel Cost Calculator to estimate fuel used and total trip expense from distance, fuel efficiency, and fuel price.
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.
BMR — Basal Metabolic Rate (Mifflin–St Jeor)
Use the BMR to estimate basal metabolic rate. Review inputs, results, limitations, safety guidance, and FAQs.
CPM Calculator
Use this cpm calculator to calculate cost per thousand impressions, implied cost, or required impressions. Review inputs, formulas, examples, limitations, and
Sales Tax Calculator
Use this sales tax calculator to calculate sales tax amount, pre-tax subtotal, and final total. Review inputs, formulas, examples, limitations, and FAQs.
Final Grade Calculator
Find the final exam score needed to reach a target grade or estimate the course result from an expected exam score.
Projectile Motion Calculator
Use our Projectile Motion Calculator to find time of flight, range, maximum height, time to peak, and velocity components from speed, angle, height, and gravity.
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,
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.
Running Calorie Calculator
Use this running calorie calculator to estimate estimated calories used during a run. Learn the inputs, formulas, examples, limitations, training tips, and FA
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.
Bikini Calculator
Use our Bikini Calculator to estimate your body shape from bust, waist, high hip, and hip measurements, then get bikini style suggestions that fit your shape.
GPA calculator
Calculate semester GPA and estimate cumulative GPA from course grade points and credit hours, with clear formulas and policy guidance.
One Rep Max Calculator
Estimate your one-repetition maximum from a completed submaximal set and translate it into practical training percentages.
Percentage Calculator
Percentage calculator for percent of a number, what percent one value is of another, and finding the whole from a percent.
Atom Calculator
Use our Atom Calculator to find protons, neutrons, electrons, atomic number, mass number, and ionic charge quickly from standard atomic relationships.
Scientific Calculator
Evaluate scientific expressions involving powers, roots, logarithms, constants and trigonometric functions.
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.
Waist-to-Height Ratio (WHtR) Calculator
Use the Waist-to-Height Ratio Calculator to estimate waist-to-height ratio. Review inputs, results, limitations, safety guidance, and FAQs.
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.
Free JPG to PNG Converter
Convert JPG images to PNG format with the embedded converter on this page.
Density Calculator
Calculate density, mass, or volume with unit conversion, worked examples, and clear guidance about temperature, mixtures, and measurement precision.
Exponent Calculator
Exponent Calculator helps you solve powers, positive and negative exponents, and exponential values quickly with clear, accurate results.
APY Calculator
Use this apy calculator to calculate effective annual percentage yield and one-year growth factor. Review inputs, formulas, examples, limitations, and FAQs.
Beam Deflection Calculator
Estimate elastic beam deflection for common cantilever and simply supported cases using span, load, elastic modulus, and second moment of area.
Dividend Calculator
Use this dividend calculator to calculate periodic and annual dividend income, yield, and projected reinvestment growth. Review inputs, formulas, examples, li
Dog Pregnancy (Due Date) Calculator
Use the Dog Pregnancy Due Date Calculator to estimate a whelping date and delivery window from mating, ovulation, LH surge, or diestrus.
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.
Ideal Weight Calculator
Use the Ideal Weight Calculator to estimate formula-based ideal body weight. Review inputs, results, limitations, safety guidance, and FAQs.
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
Mixed Number Calculator
Calculate with mixed numbers by converting whole-and-fraction parts to improper fractions and simplifying.
CGPA Calculator
Calculate cumulative CGPA from semester GPA and credit hours with a credit-weighted formula, worked example, and policy checks.
Half-Life Calculator
Calculate remaining quantity, elapsed time, half-life, decay constant, or mean lifetime with formulas, steps, units, and a worked example.
Basis Point (BPS) Calculator
Use this basis point (bps) calculator to calculate rate difference in basis points, percentage points, and decimal form. Review inputs, formulas, examples, li
Free SVG Converter
Use the embedded SVG converter below. Check the tool for its available options and instructions.
LCM Calculator
Find the least common multiple of integers using prime factors or the relationship between LCM and GCF.
Marathon Pace Calculator
Use this marathon pace calculator to estimate required average pace, speed, and checkpoint splits. Learn the inputs, formulas, examples, limitations, training
Surface Area Calculator
Find lateral or total surface area for common three-dimensional solids in square units.
Refinance Calculator
Use this refinance calculator to calculate estimated payment change, interest difference. Review key inputs, formulas, scenarios, limitations, and FAQs.
VAT Calculator
Use this vat calculator to calculate tax amount, price before tax, and price including tax. Review inputs, formulas, examples, limitations, and FAQs.
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.
Macro Calculator
Estimate daily calories and divide them into protein, carbohydrate and fat targets for general planning.
Circle Skirt Calculator
Circle Skirt Calculator to find waist radius, hem measurements, and fabric requirements for full, half, or quarter skirts.
Room Size Calculator
Calculate a rectangular room’s floor, ceiling, wall area, perimeter and volume from inside dimensions.
Lean Body Mass Calculator
Use the Lean Body Mass Calculator to estimate lean body mass. Review inputs, results, limitations, safety guidance, and FAQs.
Image Cropper
Crop JPG, PNG and WebP images with free or fixed ratios, exact dimensions, rotation, flipping and export controls.
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.
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.
Commission Calculator
Use this commission calculator to calculate commission earned and combined compensation. Review key inputs, formulas, scenarios, limitations, and FAQs.
Protein Calculator
Estimate a daily protein range from body weight, activity and goal for general nutrition planning.
Gas cost calculator
Gas Cost Calculator to estimate gasoline needed, trip fuel spend, and total driving cost by distance, mpg, and gas price.