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.
Plastic Footprint Calculator
Estimate annual household plastic use in kilograms and pounds from common disposable items, frequencies and model item weights.
Topsoil Calculator
Estimate topsoil volume, bags or mass from the measured area, fill depth and the supplier’s product information.
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
Air Conditioner Size Calculator
Estimate a room air conditioner’s preliminary BTU and tonnage range from dimensions and major load factors.
Interest Rate Calculator
Solve for interest rate, principal, balance, or time while distinguishing simple, compound, nominal, and effective rate assumptions.
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.
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.
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.
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.
Free SVG Converter
Use the embedded SVG converter below. Check the tool for its available options and instructions.
t-test Calculator
Use our T-Test Calculator to compute t statistic, p-value, confidence interval, and conclusion for one-sample, Welch, pooled, or paired t-tests.
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.
Adjusted Body Weight Calculator
Use the Adjusted Body Weight Calculator to estimate adjusted body weight. Review inputs, results, limitations, safety guidance, and FAQs.
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.
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.
Avogadro’s number calculator
Convert between moles and representative particles using the exact Avogadro constant, with examples for atoms, molecules, ions, and formula units.
Gas cost calculator
Gas Cost Calculator to estimate gasoline needed, trip fuel spend, and total driving cost by distance, mpg, and gas price.
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.
Inches to Fraction Calculator
Inches to Fraction Calculator converts decimal inch values into usable fractions for construction, woodworking, machining, and daily measurements.
Image Cropper
Crop JPG, PNG and WebP images with free or fixed ratios, exact dimensions, rotation, flipping and export controls.
Blood Type Calculator
Use the Blood Type Calculator to estimate possible child blood types. Review inputs, results, limitations, safety guidance, and FAQs.
Average Percentage Calculator
Average percentage calculator to find simple or weighted averages of multiple percentages with quick, accurate results.
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.
Steps to Miles Calculator
Use this steps to miles calculator to estimate estimated distance in miles and kilometers. Learn the inputs, formulas, examples, limitations, training tips, a
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.
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.
Percentage Calculator
Percentage calculator for percent of a number, what percent one value is of another, and finding the whole from a percent.
LCM Calculator
Find the least common multiple of integers using prime factors or the relationship between LCM and GCF.
Kinetic Energy Calculator
Calculate translational kinetic energy from mass and velocity, rearrange the formula, convert units, and explore the squared effect of speed.
Stair Calculator
Estimate uniform risers, tread count, total run, angle and stringer length for a straight stair concept.
Molarity Calculator
Use our Molarity Calculator to find moles, mass concentration, and molarity from solute mass, molar mass, and solution volume.
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.
Proportion Calculator
Solve a missing value in equivalent ratios and verify the result using equal cross products.
Period Calculator
Predict your next period start/end, ovulation day, and fertile window from LMP and cycle length with this free period calculator.
Marathon Pace Calculator
Use this marathon pace calculator to estimate required average pace, speed, and checkpoint splits. Learn the inputs, formulas, examples, limitations, training
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.
Personal Loan Calculator
Use this personal loan calculator to calculate estimated payment, total interest. Review key inputs, formulas, scenarios, limitations, and FAQs.
Dog Size & Adult Weight Calculator
Use our Dog Size & Adult Weight Calculator to estimate your puppy’s adult weight from age and current weight. Quick size prediction with pet category output.
Mulch Calculator
Calculate mulch volume and full bags from landscape-bed area and the finished depth you intend to maintain.
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.
Percent Yield Calculator
Use our Percent Yield Calculator to calculate chemistry percent yield from actual yield and theoretical yield in mg, g, or kg.
Teen BMI calculator
Use the Teen BMI calculator to estimate a teen BMI percentile. Review inputs, results, limitations, safety guidance, and FAQs.
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.
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.
FFMI Calculator (Fat-Free Mass Index)
Use the FFMI Calculator to estimate fat-free mass index. Review inputs, results, limitations, safety guidance, and FAQs.
Roofing Shingle Calculator
Estimate sloped roof area, roofing squares and bundles from footprint, pitch and a complexity allowance.
Brick Calculator
Estimate brick quantity from net wall area, the brick face, mortar joint, openings and practical waste.
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.
Winning Percentage Calculator
Use this winning percentage calculator to estimate winning percentage, total games, and record comparisons. Learn the inputs, formulas, examples, limitations,
Weighted Grade Calculator
Calculate a weighted course grade from category percentages and weights, including the normalized grade so far and remaining weight.
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.
Atom Calculator
Use our Atom Calculator to find protons, neutrons, electrons, atomic number, mass number, and ionic charge quickly from standard atomic relationships.
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.
Quadratic Formula Calculator
Solve a quadratic equation from coefficients a, b and c and interpret its discriminant and roots.
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
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
Emergency Fund Calculator
Use this emergency fund calculator to calculate recommended reserve target, current shortfall. Review key inputs, formulas, scenarios, limitations, and FAQs.
Weight Gain Calculator
Use the Weight Gain Calculator to estimate a calorie surplus for weight gain. Review inputs, results, limitations, safety guidance, and FAQs.
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.
Break-Even Calculator
Use this break-even calculator to calculate break-even units, break-even revenue. Review key inputs, formulas, scenarios, limitations, and FAQs.
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.
Cholesterol Ratio Calculator
Use the Cholesterol Ratio Calculator to estimate cholesterol ratios. Review inputs, results, limitations, safety guidance, and FAQs.
GPA calculator
Calculate semester GPA and estimate cumulative GPA from course grade points and credit hours, with clear formulas and policy guidance.
Investment Calculator
Use this investment calculator to calculate projected future value, total contributions. Review key inputs, formulas, scenarios, limitations, and FAQs.
Refinance Calculator
Use this refinance calculator to calculate estimated payment change, interest difference. Review key inputs, formulas, scenarios, limitations, and FAQs.
Theoretical Yield Calculator
Theoretical Yield Calculator to find the maximum product yield from stoichiometry, limiting reagent, and molar relationships.
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.
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
Body Fat Calculator
Use the Body Fat Calculator to estimate body-fat percentage. Review inputs, results, limitations, safety guidance, and FAQs.
Paver Calculator
Estimate whole pavers for a patio or walkway using actual dimensions, joint width, pattern and cutting waste.
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.
Paint Calculator
Estimate wall-paint quantity from room dimensions, openings, coats, coverage and a practical allowance.
Percent Off Calculator
Use this percent off calculator to calculate discount amount, sale price, and total savings. Review inputs, formulas, examples, limitations, and FAQs.
Density Calculator
Calculate density, mass, or volume with unit conversion, worked examples, and clear guidance about temperature, mixtures, and measurement precision.
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.
Velocity Calculator
Calculate average velocity, displacement, or elapsed time with unit conversion and clear guidance about direction and the difference between speed and velocity.
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,.
Credit Card Interest Calculator
Estimate credit card interest, payoff time, and total repayment cost using balance, APR, payment amount, and compounding assumptions.
Image Color Picker
Pick an exact pixel from an uploaded image and copy its color in HEX, RGB, HSL, HSV, CMYK or OKLCH formats.
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.
Korean Age Calculator
Korean Age Calculator helps you convert your age using the traditional Korean age system quickly and clearly.
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.
Time Calculator
Time Calculator helps you add, subtract, and measure time differences in hours and minutes with ease.
Favicon Generator
Turn one logo or image into ICO, PNG and app-icon files with crop, padding, mask and background controls.
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.
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
Lottery Tax Calculator
Use this lottery tax calculator to calculate estimated withholding and after-tax proceeds. Review inputs, formulas, examples, limitations, and FAQs.
Mortgage Calculator with Taxes and Insurance
Use this mortgage calculator with taxes and insurance to calculate estimated total monthly housing payment and component breakdown. Review key inputs,.
All-in-one Home Loan Calculator
Use this all-in-one home loan calculator to calculate estimated payment, cash needed, amortization, affordability indicators, and total loan cost. Review inpu
Lean Body Mass Calculator
Use the Lean Body Mass Calculator to estimate lean body mass. Review inputs, results, limitations, safety guidance, and FAQs.
Data Unit Converter
Convert bits and bytes across decimal and binary storage units while seeing the exact factor used for every result.
Mortgage Interest Calculator
Use this mortgage interest calculator to calculate estimated interest by period, total interest. Review key inputs, formulas, scenarios, limitations, and.
Loan Comparison Calculator
Use this loan comparison calculator to calculate monthly payment, total interest. Review key inputs, formulas, scenarios, limitations, and FAQs.
Dose Calculator
Check dose arithmetic from an already verified prescription or label, including mg/kg, total mg and liquid volume conversions.
Image Compressor
Compress JPG, PNG, WebP, and SVG images in your browser. Choose JPEG or WebP output, adjust quality, resize dimensions, and download.
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.
Gravel Calculator
Use our Gravel Calculator to estimate gravel volume, weight, tons, cubic yards, coverage, and total cost from area, depth, density, and price.
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.
Tile Calculator
Estimate tiles, edge cuts and full boxes using the project size, tile dimensions, grout gap and waste allowance.