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.
Favicon Generator
Turn one logo or image into ICO, PNG and app-icon files with crop, padding, mask and background controls.
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.
Protein Calculator
Estimate a daily protein range from body weight, activity and goal for general nutrition planning.
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,
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.
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.
Mixed Number Calculator
Calculate with mixed numbers by converting whole-and-fraction parts to improper fractions and simplifying.
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.
Credit Card Interest Calculator
Estimate credit card interest, payoff time, and total repayment cost using balance, APR, payment amount, and compounding assumptions.
Plastic Footprint Calculator
Estimate annual household plastic use in kilograms and pounds from common disposable items, frequencies and model item weights.
Wallpaper Calculator
Estimate wallpaper strips and full rolls using wall height, perimeter, roll size, trimming and pattern repeat.
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!
Maintenance Calorie Calculator
Use the Maintenance Calorie Calculator to estimate maintenance calories. Review inputs, results, limitations, safety guidance, and FAQs.
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.
Atom Calculator
Use our Atom Calculator to find protons, neutrons, electrons, atomic number, mass number, and ionic charge quickly from standard atomic relationships.
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.
LCM Calculator
Find the least common multiple of integers using prime factors or the relationship between LCM and GCF.
Stock Calculator
Use this stock calculator to calculate cost basis, proceeds, gain or loss, and percentage return. Review inputs, formulas, examples, limitations, and FAQs.
Desk Height Calculator
Use our Desk Height Calculator to estimate ergonomic chair height, desk height, and monitor height for sitting or standing work.
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
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.
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.
Child Height Percentile Calculator
Use the Child Height Percentile Calculator to estimate a child height percentile. Review inputs, results, limitations, safety guidance, and FAQs.
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.
VAT Calculator
Use this vat calculator to calculate tax amount, price before tax, and price including tax. Review inputs, formulas, examples, 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.
Interest Rate Calculator
Solve for interest rate, principal, balance, or time while distinguishing simple, compound, nominal, and effective rate assumptions.
Door and Window Area Calculator
Total rectangular door and window opening area and perimeter while distinguishing unit and rough-opening sizes.
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
Car Finance Calculator
Use this car finance calculator to calculate amount financed, monthly payment, total interest, and total loan cost. Review inputs, formulas, examples, limitat
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.
Water Intake Calculator
Estimate a general daily hydration target from body weight, activity and climate, with practical guidance on interpreting 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.
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.
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.
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.
Salary calculator
Convert gross salary among annual, monthly, weekly, daily, and hourly amounts using your actual work schedule and paid-time assumptions.
Cholesterol Ratio Calculator
Use the Cholesterol Ratio Calculator to estimate cholesterol ratios. Review inputs, results, limitations, safety guidance, and FAQs.
Personal Loan Calculator
Use this personal loan calculator to calculate estimated payment, total interest. Review key inputs, formulas, scenarios, limitations, and FAQs.
Mortgage Calculator
Use this mortgage calculator to calculate estimated principal-and-interest payment, total interest. Review key inputs, formulas, scenarios, limitations,.
Dilution Ratio Calculator
Use our Dilution Ratio Calculator to calculate concentrate, water, final volume, or dilution ratio for water-to-concentrate mixes.
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.
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.
Test Grade Calculator
Calculate a test percentage from correct or wrong answers, view the fraction, customize letter-grade thresholds, and build a score reference.
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
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.
Insulation Calculator
Estimate net insulation area and packages while checking R-value, cavity and product coverage separately.
Paint Calculator
Estimate wall-paint quantity from room dimensions, openings, coats, coverage and a practical allowance.
Weighted Grade Calculator
Calculate a weighted course grade from category percentages and weights, including the normalized grade so far and remaining weight.
Macro Calculator
Estimate daily calories and divide them into protein, carbohydrate and fat targets for general planning.
IQ PERCENTILE CALCULATOR
Use our IQ Percentile Calculator to convert an IQ score into percentile rank, percent above, and percent below using SD 15 or SD 16 normal-distribution scales.
Ramp Calculator
Use our Ramp Calculator to find ramp slope angle, grade percent, run, and ramp length from rise, ratio, or accessibility ramp presets.
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.
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.
Commission Calculator
Use this commission calculator to calculate commission earned and combined compensation. Review key inputs, formulas, scenarios, limitations, and FAQs.
Benadryl Dosage Calculator for Dogs
A safety-first calculator for vet-approved diphenhydramine arithmetic, with checks for dog weight, product ingredients, interactions, and urgent warning signs.
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.
Lease Calculator
Use this lease calculator to calculate estimated monthly lease payment, depreciation charge. Review key inputs, formulas, scenarios, limitations, and FAQs.
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.
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.
Hiking Calorie Calculator
Estimate calories burned on a hike using weight, moving time, distance, elevation, terrain and backpack load.
Pressure Calculator
Calculate pressure, force, or area with common pressure-unit conversions and guidance about normal force, area, and gauge versus absolute pressure.
Hair Growth Calculator
Use our Hair Growth Calculator to estimate hair growth, final hair length, or time needed to reach a hair length goal using average growth rates.
Rounding Calculator
Round numbers to a selected place or significant figures and distinguish common rounding methods.
Percentage Decrease Calculator
Percentage decrease calculator to find the drop between two values or solve the missing initial, final, or decrease percentage fast.
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
Minutes to Hours Converter
Minutes to Hours Converter to instantly convert minutes into decimal hours or hours and minutes with clear results.
Percentage Increase Calculator
Find the percentage increase between two numbers. Enter original and new values to get % increase, change amount, and final value. Reverse solve from % too. Instant steps & PDF.
FFMI Calculator (Fat-Free Mass Index)
Use the FFMI Calculator to estimate fat-free mass index. Review inputs, results, limitations, safety guidance, and FAQs.
Flooring Calculator
Calculate floor area, cutting waste and the number of complete flooring boxes or rolls to purchase.
Acceleration Calculator
Calculate average acceleration from initial velocity, final velocity, and elapsed time while keeping direction, signs, and units consistent.
Proportion Calculator
Solve a missing value in equivalent ratios and verify the result using equal cross products.
Circle Skirt Calculator
Circle Skirt Calculator to find waist radius, hem measurements, and fabric requirements for full, half, or quarter skirts.
Mortgage Interest Calculator
Use this mortgage interest calculator to calculate estimated interest by period, total interest. Review key inputs, formulas, scenarios, limitations, and.
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.
Lottery Tax Calculator
Use this lottery tax calculator to calculate estimated withholding and after-tax proceeds. Review inputs, formulas, examples, limitations, and FAQs.
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.
Adjusted Body Weight Calculator
Use the Adjusted Body Weight Calculator to estimate adjusted body weight. Review inputs, results, limitations, safety guidance, and FAQs.
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.
ABSI (A Body Shape Index) Calculator
Use the ABSI Calculator to estimate A Body Shape Index. Review inputs, results, limitations, safety guidance, and FAQs.
Triangle Calculator
Solve a triangle’s missing sides, angles, area and perimeter from sufficient known measurements.
Final Grade Calculator
Find the final exam score needed to reach a target grade or estimate the course result from an expected exam score.
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.
Outlier Calculator (Tukey Fences)
Use our Outlier Calculator to find low and high outliers with Tukey fences and the IQR method. Get Q1, Q3, IQR, fences, counts, and sorted data fast.
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.
Velocity Calculator
Calculate average velocity, displacement, or elapsed time with unit conversion and clear guidance about direction and the difference between speed and velocity.
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.
Density Calculator
Calculate density, mass, or volume with unit conversion, worked examples, and clear guidance about temperature, mixtures, and measurement precision.
Blood Pressure Category Calculator
Classify an adult blood pressure reading and calculate pulse pressure and estimated mean arterial pressure, with measurement guidance.
Creatinine Clearance Calculator
Estimate creatinine clearance with the Cockcroft-Gault equation and review the assumptions, units and limitations behind the result.
Body Fat Calculator
Use the Body Fat Calculator to estimate body-fat percentage. Review inputs, results, limitations, safety guidance, and FAQs.
Image Converter Pro
Convert images among supported formats while managing quality, transparency, dimensions, metadata, file size, and browser compatibility.
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
Grams To Ounces Calculator
Use our Grams to Ounces Calculator to convert grams to ounces, ounces to grams, kilograms, milligrams, and troy ounces.
Calories Burned Calculator
Use this calories burned calculator to estimate estimated exercise energy expenditure in calories. Learn the inputs, formulas, examples, limitations, training
Waist-to-Hip Ratio (WHR) Calculator
Use the Waist-to-Hip Ratio Calculator to estimate waist-to-hip ratio. Review inputs, results, limitations, safety guidance, and FAQs.
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
Long Division Calculator
Perform long division with a quotient, remainder and step-by-step divide-multiply-subtract work.
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
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.