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.
Cholesterol Units Converter
Convert cholesterol and triglyceride measurements between mg/dL and mmol/L with analyte-specific factors and careful result interpretation.
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.
Drywall Calculator
Estimate whole drywall sheets for walls and an optional ceiling using room dimensions, panel size and waste.
Fraction Calculator
Calculate fraction operations, simplify the result and understand common denominators and reciprocals.
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.
Percent Yield Calculator
Use our Percent Yield Calculator to calculate chemistry percent yield from actual yield and theoretical yield in mg, g, or kg.
Circle Skirt Calculator
Circle Skirt Calculator to find waist radius, hem measurements, and fabric requirements for full, half, or quarter skirts.
Image Converter Pro
Convert images among supported formats while managing quality, transparency, dimensions, metadata, file size, and browser compatibility.
PayPal Fee Calculator
Estimate transaction fees, net receipts, or a gross request amount using the current percentage and fixed fee for your transaction type.
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.
Interest Rate Calculator
Solve for interest rate, principal, balance, or time while distinguishing simple, compound, nominal, and effective rate assumptions.
Personal Loan Calculator
Use this personal loan calculator to calculate estimated payment, 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
Document + PDF Converter
Convert supported documents to or from PDF while checking layout fidelity, fonts, page order, privacy, file limits, and output compatibility.
Dose Calculator
Check dose arithmetic from an already verified prescription or label, including mg/kg, total mg and liquid volume conversions.
Salary calculator
Convert gross salary among annual, monthly, weekly, daily, and hourly amounts using your actual work schedule and paid-time assumptions.
Adjusted Body Weight Calculator
Use the Adjusted Body Weight Calculator to estimate adjusted body weight. Review inputs, results, limitations, safety guidance, and FAQs.
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.
LCM Calculator
Find the least common multiple of integers using prime factors or the relationship between LCM and GCF.
Volume Calculator
Calculate the volume of common three-dimensional solids using measurements in compatible units.
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.
Paver Calculator
Estimate whole pavers for a patio or walkway using actual dimensions, joint width, pattern and cutting waste.
Favicon Generator
Turn one logo or image into ICO, PNG and app-icon files with crop, padding, mask and background controls.
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 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.
Exponent Calculator
Exponent Calculator helps you solve powers, positive and negative exponents, and exponential values quickly with clear, accurate results.
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.
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.
Macro Calculator
Estimate daily calories and divide them into protein, carbohydrate and fat targets for general planning.
Roof Pitch Calculator
Roof Pitch Calculator helps you find roof pitch, slope, angle, and rise-to-run values quickly for roofing, planning, and construction work.
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,.
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.
Image Color Picker
Pick an exact pixel from an uploaded image and copy its color in HEX, RGB, HSL, HSV, CMYK or OKLCH formats.
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.
Pythagorean Theorem Calculator
Pythagorean Theorem Calculator solves missing sides of a right triangle fast. Use it to find the hypotenuse or any unknown side easily.
Velocity Calculator
Calculate average velocity, displacement, or elapsed time with unit conversion and clear guidance about direction and the difference between speed and velocity.
Mortgage Calculator
Use this mortgage calculator to calculate estimated principal-and-interest payment, total interest. Review key inputs, formulas, scenarios, limitations,.
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.
Free JPG to PNG Converter
Convert JPG images to PNG format with the embedded converter on this page.
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.
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.
Basic Calculator
Perform everyday arithmetic with decimals, signs, parentheses and common percentage operations.
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
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
Running Split Calculator
Use this running split calculator to estimate cumulative and segment times for each split. Learn the inputs, formulas, examples, limitations, training tips, a
Calorie Calculator
Use the Calorie Calculator to estimate daily calorie needs. Review inputs, results, limitations, safety guidance, and FAQs.
Investment Calculator
Use this investment calculator to calculate projected future value, total contributions. Review key inputs, formulas, scenarios, limitations, and FAQs.
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.
Topsoil Calculator
Estimate topsoil volume, bags or mass from the measured area, fill depth and the supplier’s product information.
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.
Blood Type Calculator
Use the Blood Type Calculator to estimate possible child blood types. 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.
Work and Power Calculator
Calculate mechanical work and average power from force, displacement, angle, and elapsed time, with clear joule and watt interpretation.
BMI Calculator (Body Mass Index)
Use the BMI Calculator to estimate adult body mass index. Review inputs, results, limitations, safety guidance, and FAQs.
Door and Window Area Calculator
Total rectangular door and window opening area and perimeter while distinguishing unit and rough-opening sizes.
Molarity Calculator
Use our Molarity Calculator to find moles, mass concentration, and molarity from solute mass, molar mass, and solution volume.
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.
Wallpaper Calculator
Estimate wallpaper strips and full rolls using wall height, perimeter, roll size, trimming and pattern repeat.
Credit Card Interest Calculator
Estimate credit card interest, payoff time, and total repayment cost using balance, APR, payment amount, and compounding assumptions.
Fraction to Decimal Calculator
Convert a fraction to terminating or repeating decimal form and understand when rounding is required.
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.
Percentage Calculator
Percentage calculator for percent of a number, what percent one value is of another, and finding the whole from a percent.
Air Conditioner Size Calculator
Estimate a room air conditioner’s preliminary BTU and tonnage range from dimensions and major load factors.
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.
Brick Calculator
Estimate brick quantity from net wall area, the brick face, mortar joint, openings and practical waste.
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
Percent Off Calculator
Use this percent off calculator to calculate discount amount, sale price, and total savings. Review inputs, formulas, examples, limitations, and FAQs.
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
Period Calculator
Predict your next period start/end, ovulation day, and fertile window from LMP and cycle length with this free period calculator.
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
Water Intake Calculator
Estimate a general daily hydration target from body weight, activity and climate, with practical guidance on interpreting the result.
Weight Gain Calculator
Use the Weight Gain Calculator to estimate a calorie surplus for weight gain. Review inputs, results, limitations, safety guidance, and FAQs.
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.
Test Grade Calculator
Calculate a test percentage from correct or wrong answers, view the fraction, customize letter-grade thresholds, and build a score reference.
AGE CALCULATOR
Age Calculator helps you find exact age in years, months, and days from your date of birth instantly.
Cholesterol Ratio Calculator
Use the Cholesterol Ratio Calculator to estimate cholesterol ratios. Review inputs, results, limitations, safety guidance, and FAQs.
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.
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.
Beam Deflection Calculator
Estimate elastic beam deflection for common cantilever and simply supported cases using span, load, elastic modulus, and second moment of area.
Creatinine Clearance Calculator
Estimate creatinine clearance with the Cockcroft-Gault equation and review the assumptions, units and limitations behind the result.
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.
Proportion Calculator
Solve a missing value in equivalent ratios and verify the result using equal cross products.
Long Division Calculator
Perform long division with a quotient, remainder and step-by-step divide-multiply-subtract work.
Harris-Benedict Calculator (Basal Metabolic Rate)
Use the Harris-Benedict Calculator to estimate basal metabolic rate. Review inputs, results, limitations, safety guidance, and FAQs.
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.
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.
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.
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
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,
Time Calculator
Time Calculator helps you add, subtract, and measure time differences in hours and minutes with ease.
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.
GPA calculator
Calculate semester GPA and estimate cumulative GPA from course grade points and credit hours, with clear formulas and policy guidance.
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.
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,
Gravel Calculator
Use our Gravel Calculator to estimate gravel volume, weight, tons, cubic yards, coverage, and total cost from area, depth, density, and price.
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.
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
Fraction to Percentage Calculator
Convert fractions to percentages and percentages to simplified fractions. Enter numerator, denominator, or percent to get quick live results.
mg to mL Calculator
Use our mg to mL Calculator to convert weight and volume using liquid density, preset liquids, or medication concentration in mg/mL or mg/5 mL.