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.
Power Analysis Calculator
Use our Power Analysis Calculator to estimate sample size per group, statistical power, and minimum detectable effect for a two-sample mean test with alpha and standard deviation.
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.
Long Division Calculator
Perform long division with a quotient, remainder and step-by-step divide-multiply-subtract work.
Dose Calculator
Check dose arithmetic from an already verified prescription or label, including mg/kg, total mg and liquid volume conversions.
Room Size Calculator
Calculate a rectangular room’s floor, ceiling, wall area, perimeter and volume from inside dimensions.
Free Fall Calculator
Use our Free Fall Calculator to find time, distance, final velocity, and average speed from height or time with gravity presets and unit conversion.
Rounding Calculator
Round numbers to a selected place or significant figures and distinguish common rounding methods.
Cycling Calorie Calculator
Estimate calories burned while cycling from body weight, duration, pace and ride conditions, with guidance for interpreting MET-based results.
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.
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.
Image Compressor
Compress JPG, PNG, WebP, and SVG images in your browser. Choose JPEG or WebP output, adjust quality, resize dimensions, and download.
Walking Calorie Calculator
Use this walking calorie calculator to estimate estimated calories used during a walk. Learn the inputs, formulas, examples, limitations, training tips, and F
Mortgage Calculator
Use this mortgage calculator to calculate estimated principal-and-interest payment, total interest. Review key inputs, formulas, scenarios, limitations,.
PAY RAISE CALCULATOR
Use this pay raise calculator to calculate new pay, increase per period, and annualized difference. Review inputs, formulas, examples, limitations, and FAQs.
Drywall Calculator
Estimate whole drywall sheets for walls and an optional ceiling using room dimensions, panel size and waste.
Stock Calculator
Use this stock calculator to calculate cost basis, proceeds, gain or loss, and percentage return. Review inputs, formulas, examples, 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.
Loan Comparison Calculator
Use this loan comparison calculator to calculate monthly payment, total interest. Review key inputs, formulas, scenarios, limitations, and FAQs.
Percentage Decrease Calculator
Percentage decrease calculator to find the drop between two values or solve the missing initial, final, or decrease percentage fast.
Wavelength → Frequency Calculator
Use our Wavelength to Frequency Calculator to find frequency from wavelength with vacuum, air, water, or custom wave speed. Fast SI-based results online.
FFMI Calculator (Fat-Free Mass Index)
Use the FFMI Calculator to estimate fat-free mass index. Review inputs, results, limitations, safety guidance, and FAQs.
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.
Bird Age Calculator
Use our Bird Age Calculator to convert bird years to human years or human age back to bird age by species or custom lifespan.
Free SVG Converter
Transform your SVG vector artwork into PNG, JPEG, or WebP formats safely and easily. Preserve quality and enhance your designs for any project with our tool.
Percent Yield Calculator
Use our Percent Yield Calculator to calculate chemistry percent yield from actual yield and theoretical yield in mg, g, or kg.
Percentage of a Percentage Calculator
Percentage of a percentage calculator to find cumulative percentage and final value from two related percentage changes.
Density Calculator
Calculate density, mass, or volume with unit conversion, worked examples, and clear guidance about temperature, mixtures, and measurement precision.
APY Calculator
Use this apy calculator to calculate effective annual percentage yield and one-year growth factor. Review inputs, formulas, examples, limitations, 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.
Prime Factorization Calculator
Break a positive integer into its unique product of prime powers and review factor-tree logic.
Cord of Wood Calculator
Use our Cord of Wood Calculator to estimate firewood stack volume, full cords, face cords, cord percentage, and cost from stack dimensions.
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 Calculator
Percentage calculator for percent of a number, what percent one value is of another, and finding the whole from a percent.
Blood Type Calculator
Use the Blood Type Calculator to estimate possible child blood types. Review inputs, results, limitations, safety guidance, and FAQs.
Half-Life Calculator
Calculate remaining quantity, elapsed time, half-life, decay constant, or mean lifetime with formulas, steps, units, and a worked example.
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.
Sample Size Calculator
Use our Sample Size Calculator to estimate sample size for a mean or proportion from confidence level, margin of error, and optional finite population correction.
Stair Calculator
Estimate uniform risers, tread count, total run, angle and stringer length for a straight stair concept.
Student Loan Calculator
Use this student loan calculator to calculate estimated payment, payoff time. 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.
Ohm’s Law Current Calculator
Use our Ohm’s Law Current Calculator to find current from voltage and resistance. Get instant results in A, mA, or µA plus power and conductance.
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
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.
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
Salary calculator
Convert gross salary among annual, monthly, weekly, daily, and hourly amounts using your actual work schedule and paid-time assumptions.
Time Calculator
Time Calculator helps you add, subtract, and measure time differences in hours and minutes with ease.
Fraction to Decimal Calculator
Convert a fraction to terminating or repeating decimal form and understand when rounding is required.
USA Annual Income Calculator
Use this usa annual income calculator to calculate gross annual income and equivalent pay-period amounts. Review inputs, formulas, examples, limitations, and
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.
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.
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.
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.
Acceleration Calculator
Calculate average acceleration from initial velocity, final velocity, and elapsed time while keeping direction, signs, and units consistent.
Roofing Shingle Calculator
Estimate sloped roof area, roofing squares and bundles from footprint, pitch and a complexity allowance.
Decking Calculator
Estimate deck-board rows, pieces and linear length using actual board dimensions, spacing, direction and waste.
Calories Burned Calculator
Use this calories burned calculator to estimate estimated exercise energy expenditure in calories. Learn the inputs, formulas, examples, limitations, training
CPM Calculator
Use this cpm calculator to calculate cost per thousand impressions, implied cost, or required impressions. Review inputs, formulas, examples, limitations, and
Chi-Square Calculator
Use our Chi-Square Calculator to run goodness-of-fit and independence tests, or find right-tail p-values and critical χ² values from df and alpha.
Cholesterol Ratio Calculator
Use the Cholesterol Ratio Calculator to estimate cholesterol ratios. Review inputs, results, limitations, safety guidance, and FAQs.
Theoretical Yield Calculator
Theoretical Yield Calculator to find the maximum product yield from stoichiometry, limiting reagent, and molar relationships.
Free JPG to PNG Converter
Convert your JPG images to PNG format effortlessly with our free online converter. Fast, easy, and no downloads required—start converting today!
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
Hiking Calorie Calculator
Estimate calories burned on a hike using weight, moving time, distance, elevation, terrain and backpack load.
Calorie Deficit Calculator
Use our Calorie Deficit Calculator to estimate BMR, maintenance calories, TDEE, calorie deficit, target calories, and weekly weight-change estimate.
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.
Grams To Calories Calculator
Estimate calories from grams of carbohydrate, protein, fat, or alcohol. Review energy factors, examples, label limitations, and six practical FAQs.
AGE CALCULATOR
Age Calculator helps you find exact age in years, months, and days from your date of birth instantly.
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.
Savings Goal Calculator
Use this savings goal calculator to calculate required periodic saving, projected growth. Review key inputs, formulas, scenarios, limitations, and FAQs.
Dilution Ratio Calculator
Use our Dilution Ratio Calculator to calculate concentrate, water, final volume, or dilution ratio for water-to-concentrate mixes.
Child Height Predictor
Use the Child Height Predictor to estimate an adult-height estimate for a child. Review inputs, results, limitations, safety guidance, and FAQs.
Heart Age Calculator
Compare an educational cardiovascular risk profile with a reference age and understand the factors influencing the estimate.
Personal Loan Calculator
Use this personal loan calculator to calculate estimated payment, total interest. Review key inputs, formulas, scenarios, limitations, and FAQs.
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.
Balance Transfer Calculator
Compare a balance transfer’s fee, promotional period, payment plan, and post-promotion APR against keeping the current credit-card balance.
Percentage Change Calculator
Use our Percentage Change Calculator to quickly find percent increase or decrease between two values. Instant results, step-by-step breakdown, free & easy to use.
Final Grade Calculator
Find the final exam score needed to reach a target grade or estimate the course result from an expected exam score.
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.
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.
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.
Exponent Calculator
Exponent Calculator helps you solve powers, positive and negative exponents, and exponential values quickly with clear, accurate results.
Plastic Footprint Calculator
Estimate annual household plastic use in kilograms and pounds from common disposable items, frequencies and model item weights.
Lottery Tax Calculator
Use this lottery tax calculator to calculate estimated withholding and after-tax proceeds. Review inputs, formulas, examples, limitations, and FAQs.
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,
Door and Window Area Calculator
Total rectangular door and window opening area and perimeter while distinguishing unit and rough-opening sizes.
Proportion Calculator
Solve a missing value in equivalent ratios and verify the result using equal cross products.
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.
Fraction Calculator
Calculate fraction operations, simplify the result and understand common denominators and reciprocals.
GPA calculator
Calculate semester GPA and estimate cumulative GPA from course grade points and credit hours, with clear formulas and policy guidance.
Minutes to Hours Converter
Minutes to Hours Converter to instantly convert minutes into decimal hours or hours and minutes with clear results.
Break-Even Calculator
Use this break-even calculator to calculate break-even units, break-even revenue. Review key inputs, formulas, scenarios, limitations, and FAQs.
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.
Test Grade Calculator
Calculate a test percentage from correct or wrong answers, view the fraction, customize letter-grade thresholds, and build a score reference.
Ramp Calculator
Use our Ramp Calculator to find ramp slope angle, grade percent, run, and ramp length from rise, ratio, or accessibility ramp presets.
Quadratic Formula Calculator
Solve a quadratic equation from coefficients a, b and c and interpret its discriminant and roots.
Work and Power Calculator
Calculate mechanical work and average power from force, displacement, angle, and elapsed time, with clear joule and watt interpretation.
Adjusted Body Weight Calculator
Use the Adjusted Body Weight Calculator to estimate adjusted body weight. Review inputs, results, limitations, safety guidance, and FAQs.
Fence Calculator
Estimate fence panels, posts and rails from route length, gates, section spacing and closed-perimeter conditions.
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.
Teen BMI calculator
Use the Teen BMI calculator to estimate a teen BMI percentile. Review inputs, results, limitations, safety guidance, and FAQs.