Free Online Calculators

80+ free online calculators for math, finance, health, sports and more. Percentage, BMI, loan, salary calculators — fast, accurate, no signup needed.

gimmecalc.com is a free online calculator portal. Find percentage, BMI, loan, interest, and calorie calculators here. All tools work directly in your browser — no downloads or registration needed.

88 calculators

Converters

Angle Converter — Degrees, Radians & Gradians

Convert angle units between degrees, radians, gradians, arcminutes, arcseconds, and turns with instant results. Useful for math, navigation, and construction projects.

Area Converter — Square Meters, Hectares, Acres & More

Convert area units between square meters, hectares, acres, square feet, and square yards instantly. Ideal for real estate, land measurement, and construction planning.

Color Converter — RGB, HEX, HSL & CMYK Formats

Convert colors between RGB, HEX, HSL, and CMYK formats instantly with live preview. Essential for web designers, front-end developers, and print design professionals.

Cooking Unit Converter — Cups, Tablespoons & Milliliters

Convert cooking measurements between teaspoons, tablespoons, cups, fluid ounces, milliliters, and liters instantly. Follow any recipe from any country with accurate volumes.

Data Storage Converter — Bytes, MB, GB & Terabytes

Convert data storage units between bytes, kilobytes, megabytes, gigabytes, and terabytes using the binary system. Perfect for comparing file sizes and storage capacity.

Data Transfer Rate Converter — Mbps, Gbps & More

Convert data transfer rate units between bps, Kbps, Mbps, Gbps, and Tbps instantly. Compare internet plans, estimate download times, and configure network equipment.

Energy Converter — Joules, Calories, kWh & BTU

Convert energy units between joules, kilojoules, calories, kilocalories, watt-hours, kilowatt-hours, and BTU with instant results. Useful for nutrition, electricity, and physics.

Force Converter — Newtons, Pound-Force & Dynes

Convert force units between newtons, kilonewtons, pound-force, dynes, and kilogram-force instantly. Essential for physics problems, engineering loads, and structural design.

Frequency Converter — Hertz, MHz, GHz & RPM

Convert frequency units between hertz, kilohertz, megahertz, gigahertz, and RPM instantly. Great for radio equipment, CPU specs, music tuning, and motor specifications.

Length Converter — Meters, Feet, Inches & Miles

Convert length and distance units between meters, centimeters, inches, feet, yards, kilometers, and miles instantly. Perfect for height, travel, and construction projects.

Number Base Converter — Binary, Hex, Decimal & More

Convert numbers between binary, octal, decimal, hexadecimal, Base32, and Base64 systems instantly. Essential for programming, networking, data encoding, and CS studies.

Power Converter — Watts, Kilowatts & Horsepower

Convert power units between watts, kilowatts, horsepower, and BTU/h with instant results. Compare car engines, home appliances, and heating system specs easily.

Pressure Converter — PSI, Bar, Atmospheres & Pascal

Convert pressure units between pascals, bars, atmospheres, PSI, and mmHg instantly. Ideal for tire pressure, weather readings, blood pressure, and engineering specs.

Roman Numeral Converter — Arabic to Roman & Back

Convert numbers between Roman and Arabic numerals instantly. Supports values from I to MMMCMXCIX (1 to 3999) and shows step-by-step conversion breakdown.

Shoe Size Converter — EU, US Men, US Women, UK & CM

Convert shoe sizes between EU, US Men, US Women, UK, and CM (Mondopoint) scales. Enter any size to instantly see equivalents in all other sizing systems worldwide.

Speed Converter — km/h, mph, m/s, Knots & More

Convert between speed units instantly — km/h, mph, m/s, knots, and more. Accurate speed conversion for driving abroad, sports analysis, aviation, and science.

Temperature Converter — Celsius, Fahrenheit & Kelvin

Convert temperatures between Celsius, Fahrenheit, and Kelvin scales instantly. Perfect for travel, cooking recipes, science homework, and weather forecast comparisons.

Time Converter — Seconds, Minutes, Hours, Days & Weeks

Convert time units between milliseconds, seconds, minutes, hours, days, and weeks with instant precision. Helpful for project planning, cooking timers, and programming.

Torque Converter — Newton-Meters & Foot-Pounds

Convert torque units between newton-meters, foot-pounds, kilogram-force meters, inch-pounds, and dyne-centimeters. Perfect for automotive, mechanical, and industrial use.

Volume Converter — Liters, Gallons, Cups & Cubic Meters

Convert volume units between liters, milliliters, gallons, pints, cups, and cubic meters with precise results. Great for cooking, fuel calculations, and science projects.

Weight Converter — Kilograms, Pounds, Ounces & More

Convert weight and mass units between kilograms, grams, pounds, ounces, tons, and milligrams with instant results. Ideal for cooking, shipping, and fitness tracking.

Fun

Age Calculator — Exact Age in Years, Months & Days

Calculate your exact age in years, months, and days from any date of birth. Instantly see total days lived, weeks, and days until your next birthday.

Billionaire Timer — How Long to Earn a Billion?

Enter your salary and see how many years, days, and working lifetimes it would take to earn a billion dollars. Wealth inequality made tangible.

Generation Calculator — Find Your Generation by Birth Year

Enter your birth year to discover which generation you belong to. Covers Baby Boomers, Gen X, Millennials, Gen Z, Gen Alpha, and Gen Beta with traits.

Love Calculator — Name Compatibility Percentage

Find out your love compatibility percentage based on two names — a fun entertainment calculator using the classic LOVES algorithm to share with friends.

Meeting Cost Calculator — Total Cost Per Meeting

Calculate the true cost of any meeting based on attendees, hourly rates, and duration. See total cost, cost per minute, and cost per attendee instantly.

Pet Age Calculator — Dog & Cat Years to Human Years

Convert your dog or cat's age to human years using veterinarian-recommended formulas. Adjusted for breed size category — small, medium, large, and giant.

Planetary Age Calculator — Your Age on Every Planet

Find out how old you would be on Mercury, Venus, Mars, Jupiter, Saturn, Uranus, and Neptune. Calculated from each planet's orbital period around the Sun.

Random Number Generator — Pick Numbers From Any Range

Generate random integers instantly within any range. Set minimum and maximum values, choose how many numbers to create, and copy the results to your clipboard in one click.

Salary in Big Macs Calculator — Purchasing Power Fun

Convert your annual salary into Big Macs, iPhones, and Tesla Model 3s. A fun way to visualize real purchasing power inspired by The Economist's Big Mac Index.

Summers Left Calculator — How Many Summers Remain?

Enter your age and life expectancy to see how many summers you have left. A perspective-shifting way to visualize the time you have for adventures.

Zodiac Compatibility Calculator — Sign Match Scores

Check how well your zodiac sign matches another using element-based astrology. Compare fire, earth, air, and water sign compatibility with percentage scores.

Health

BAC Calculator — Estimate Your Blood Alcohol Level

Estimate your blood alcohol content (BAC) from the number of drinks, body weight, sex, and hours elapsed. Includes legal driving limits for your country.

BMI Calculator — Check Your Body Mass Index Instantly

Calculate your BMI from height and weight. Check if your body mass index falls within WHO's healthy range — underweight, normal, overweight, or obese.

BMR Calculator — Basal Metabolic Rate by Mifflin-St Jeor

Calculate your Basal Metabolic Rate (BMR) using the Mifflin-St Jeor formula. Enter weight, height, age, and sex to find how many calories your body burns at rest daily.

Body Fat Percentage Calculator — Navy & Skinfold Methods

Estimate your body fat percentage using the U.S. Navy circumference method or Jackson-Pollock 3-site skinfold method and see your body composition category.

Calorie Calculator — Daily Calorie Needs & BMR

Calculate your daily calorie needs and basal metabolic rate (BMR) using the Mifflin-St Jeor formula. Enter age, weight, height, and activity level for personalized results.

Calories Burned by Activity — MET-Based Calculator

Calculate calories burned by activity, body weight, and duration using MET values. Covers running, swimming, cycling, yoga, walking, and many more exercise types.

Ideal Weight Calculator — By Height Using 4 Formulas

How much should I weigh? Calculate your ideal weight by height and sex using 4 proven formulas: Robinson, Devine, Miller and Hamwi — plus healthy BMI range.

Maximum Heart Rate Calculator — Training Zones by Age

Calculate your maximum heart rate by age using the 220-age, Tanaka, and HUNT formulas. See all five heart rate training zones from fat burn to maximum effort instantly.

Ovulation Calculator — Fertile Window & Period Tracker

Calculate your ovulation date, fertile window, and next period based on your last menstrual period and cycle length. Identify your most fertile days for conception planning.

Pregnancy Due Date Calculator — Weeks & Trimester Tracker

Calculate your estimated due date using Naegele's rule based on your last menstrual period. Shows current pregnancy week, trimester, and days remaining until delivery.

Pregnancy Weight Gain Calculator — IOM Guidelines

Track whether your pregnancy weight gain is on target week by week. Based on IOM guidelines for your pre-pregnancy BMI category with recommended ranges for all trimesters.

Sleep Cycle Calculator — Find Your Ideal Bedtime

Find the best bedtime based on your wake-up time by aligning sleep with 90-minute cycles. Shows optimal times for 3 to 6 cycles so you wake refreshed every morning.

TDEE Calculator — Total Daily Energy Expenditure

Calculate your TDEE — total daily energy expenditure based on weight, height, age, sex, and activity level. Get calorie goals for weight loss or gain.

Water Intake Calculator — Daily Hydration by Weight

Calculate how much water you should drink per day based on your weight, activity level, and climate. Results shown in litres, millilitres, and glasses.

Math

Circle Area Calculator — Radius, Diameter & Circumference

Calculate the area, circumference, and diameter of a circle from its radius or diameter. Useful for round tables, pools, lawns, pipes, and geometry homework problems.

Cylinder Calculator — Volume & Surface Area Solver

Calculate cylinder volume, total surface area, lateral surface area, and base area from radius and height. Shows formulas and step-by-step results.

Fraction Calculator — Add, Subtract, Multiply & Divide

Add, subtract, multiply, and divide fractions with step-by-step solutions. Simplify results automatically and convert between mixed numbers and improper fractions.

GPA Calculator — Semester & Cumulative Grade Average

Calculate your semester or cumulative GPA on a 4.0 scale. Enter letter grades and credit hours for each course to track your academic performance and plan improvements.

Mean, Median, Mode Calculator — Descriptive Statistics

Calculate mean, median, and mode for any set of numbers. Also computes sum, range, minimum, maximum, and other descriptive statistics.

Percentage Calculator — Find, Change & Compare Percents

Calculate percentages quickly and accurately. Find what percent a number is of another, compute percentage change, and add or subtract a percentage from any value.

Probability Calculator — Single, Joint & Binomial

Calculate probability for single events, two independent events, and binomial distributions with step-by-step solutions. Shows complement, intersection, and union results.

Quadratic Equation Calculator — Roots, Discriminant & Vertex

Solve any quadratic equation ax² + bx + c = 0 using the quadratic formula. Find real or complex roots, the discriminant value, and vertex coordinates of the parabola.

Pythagorean Theorem Calculator — Find Missing Sides

Calculate the missing side of a right triangle using the Pythagorean theorem (a² + b² = c²). Solve for the hypotenuse or either leg with step-by-step results shown.

Scientific Calculator — Trig, Logs, Powers & Constants

Solve trigonometry, logarithms, powers, and factorials with a scientific calculator supporting sin, cos, tan, log, ln, π, and e in degree or radian mode.

Slope Calculator — Rise Over Run & Line Equation

Calculate the slope between two coordinate points, find the y-intercept, and get the full line equation in slope-intercept form (y = mx + b) for algebra and geometry.

Sphere Calculator — Volume and Surface Area by Radius

Calculate the volume, surface area, and circumference of any sphere by entering its radius. Uses the formulas V = (4/3)πr³ and A = 4πr² for instant results.

Test Grade Calculator — Score Percentage & Letter Grade

Calculate your test score percentage and letter grade instantly. Enter points earned and total points to see your result on the A+ through F grading scale.

Triangle Calculator — Area, Perimeter & Angles Solver

Calculate triangle area, perimeter, and angles from sides or angles. Supports SSS, SAS, AAS modes using Heron's formula, law of cosines, and law of sines methods.

Z-Score Calculator — Standard Score & Percentile Finder

Calculate the Z-score from a value, mean, and standard deviation, or convert a Z-score to cumulative probability and percentile. Essential for statistics and data analysis.

Finance

Compound Growth Calculator — Investment & Savings Growth

Calculate compound growth with periodic contributions and see how your investments or savings grow over time. Enter initial amount, rate, and monthly additions for results.

Debt Payoff Calculator — Time to Pay Off Your Balance

Calculate how long it takes to pay off a debt or find the exact monthly payment needed to clear your balance by a target date. Shows total interest and payoff timeline.

Discount Calculator — Final Price, Savings & Per Unit

Calculate the final price after a percentage discount, how much you save, and the price per unit. Works for single items and bulk orders with instant results.

FIRE Calculator — Financial Independence, Retire Early

Calculate your FIRE number, years to financial independence, and projected retirement date. Enter current savings, monthly contributions, expenses, and withdrawal rate.

Interest Calculator — Simple & Compound Interest

Calculate simple and compound interest on your savings or investments. See how your money grows over time with annual, quarterly, monthly, or daily compounding options.

Loan Payment Calculator — Monthly Payments & Interest

Calculate monthly payments, total interest, and full repayment schedule for personal loans, car loans, and consumer credit. Enter amount, rate, and term for instant results.

Mortgage Calculator — Payments & Amortization Schedule

Calculate your monthly mortgage payment, total interest, and full amortization schedule. Enter home price, down payment percentage, interest rate, and loan term to compare.

Profit Margin Calculator — Margin, Markup & Pricing

Calculate profit margin, markup percentage, and selling price from cost. Compare margin vs markup side by side for smarter business pricing decisions.

ROI Calculator — Return on Investment Percentage

Calculate return on investment by entering your initial investment amount and net profit. Instantly see ROI percentage, total value, and compare investment profitability.

Savings Goal Calculator — Time & Monthly Amount Planner

Calculate how long it takes to reach your savings goal or find the exact monthly contribution needed. Factors in current savings and compound interest rate.

Salary to Hourly Calculator — Annual to Hourly Rate

Convert annual salary to hourly rate or hourly to annual. Set custom hours per week and weeks per year to see daily, weekly, and monthly pay breakdowns.

Tip Calculator — Split Bills & Calculate Tips

Calculate tips and split restaurant bills instantly — enter the bill amount, choose a tip percentage, and see the total and each person's share.

Utility

Date Calculator — Days, Weeks & Months Between Dates

Calculate the exact number of days, weeks, months, and years between any two dates. Perfect for project deadlines, countdown timers, and event planning.

Password Generator — Create Strong, Secure Passwords

Generate strong, random passwords with custom length, character types, and a built-in strength indicator. Protect your accounts with secure, hard-to-crack passwords.

Recipe Scaler — Adjust Ingredient Quantities Instantly

Scale any recipe up or down by changing the number of servings. Paste your ingredient list and the scaler adjusts every quantity automatically, including fractions.

Time Calculator — Add & Subtract Hours & Minutes

Add or subtract hours, minutes and seconds instantly. Perfect for work hours, shift totals and running split times. Shows total in decimal hours for payroll.

UUID Generator — Create Random v4 Identifiers

Generate random UUID v4 identifiers instantly. Create one or up to 100 unique UUIDs in a single click, copy them to clipboard, and use them in databases or API projects.

Word & Character Counter — Text Length Analyzer

Count words, characters, sentences, and paragraphs in your text instantly. Shows estimated reading time and character count with and without spaces.

Construction

Loose-Fill Insulation Calculator — Bags & R-Value

Calculate how many bags of loose-fill (blown-in) insulation you need for any area and depth, and find the R-value for mineral wool, cellulose, or EPS.

Paint Calculator — How Much Paint Do You Need?

Calculate how much paint you need for any room. Enter length, width, height, number of coats, and coverage rate to get total wall area and liters of paint required.

Square Footage Calculator — Room Area in Sq Ft & Sq M

Calculate room or space area in square feet and square meters by entering length and width. Get instant estimates for flooring, tiling, carpeting, and renovation projects.

Tile Calculator — How Many Tiles Do You Need?

Calculate how many tiles you need for any floor or wall. Enter room and tile dimensions with a waste factor to get an instant tile count and room area.

Sports

One Rep Max (1RM) Calculator — Estimate Your Max Lift

Calculate your one rep max (1RM) based on weight lifted and reps using five proven formulas: Epley, Brzycki, Lander, Lombardi, and O'Conner with averaged results.

Race Time Predictor — Estimate Your Finish Time

Predict your finish time for any race distance based on a previous result. Uses the Riegel formula to estimate pace for 5K, 10K, half marathon, and marathon distances.

Running Pace Calculator — Pace, Time & Distance

Calculate your running pace, finish time, or distance by entering any two values. Shows pace in min/km and speed in km/h for training plans and race goal setting.

Ski Size Calculator — Find Your Ideal Ski Length

Calculate the recommended ski length based on your height, weight, skiing ability, and ski type. Covers alpine, freeride, freestyle, and race skis with a size range.

Ski Binding DIN Calculator — ISO 11088 Release Value

Calculate your ski binding DIN release value based on weight, height, age, and skier type using the ISO 11088 standard. Get the right setting before hitting the slopes.

Our calculators are organized into categories so you can quickly find the tool you need — from financial calculations to health metrics.

What types of calculators are available?

We offer a wide range of free online calculators organized into categories: Finance (loan, mortgage, interest, VAT), Health (BMI, calorie, TDEE), Math (percentage, fraction, mean-median-mode), Sports (pace, race predictor, 1RM), Fun (age, love, zodiac), Utility (password generator, word counter), and Converters (length, weight, temperature and more).

How to use our calculators?

All calculators run directly in your browser with no downloads or installation required. Simply enter your values and get instant results. Every calculator is mobile-friendly and works on any device. You can also share your results by copying the URL — all input values are saved in the link.

Are the calculators free?

Yes, every calculator is completely free to use. No registration, no hidden fees, no limitations. All calculations are performed locally in your browser, which means your data stays private and is never sent to a server.

Can I embed calculators on my website?

Yes, all our calculators are available as embeddable widgets. Copy a single iframe snippet to add any calculator to your blog, CMS, or web app — no API key or registration required. The widgets adapt to your container width and support both light and dark mode.