Calculators
Fast, accurate calculators for everyday math.
Last updated: July 2026
Age Calculator
Calculate exact age in years, months and days from any date of birth — plus total months, weeks and days. Free and instant.
Percentage Calculator
Calculate percentages three ways: X% of a number, what % one number is of another, and percentage increase or decrease. Free and instant.
BMI Calculator
Calculate your Body Mass Index (BMI) in metric or imperial units and see your weight category instantly. Free and private.
Loan / EMI Calculator
Calculate your monthly loan EMI, total interest and total payment from the loan amount, interest rate and tenure. Free and instant.
Date Difference Calculator
Calculate the exact difference between two dates in years, months, days and total days, weeks and hours. Free and instant.
Tip Calculator
Calculate the tip and total bill, and split it between any number of people. Free, instant tip calculator with custom percentages.
Discount Calculator
Calculate the sale price and how much you save from an original price and a discount percentage. Free and instant.
GPA Calculator
Calculate your GPA from course grades and credit hours on a 4.0 scale. Free, instant, in-browser GPA calculator.
Compound Interest Calculator
Calculate compound interest and final balance from principal, rate, time and compounding frequency. Free, instant compound interest calculator.
Average / Mean Calculator
Calculate the mean, median, sum, count, min and max of a list of numbers. Free, instant average calculator — paste any numbers.
GST / Sales Tax Calculator
Add or remove GST / sales tax from a price at any rate, and see the net, tax and gross amounts. Free, instant calculator.
Time Duration Calculator
Calculate the duration between two times in hours and minutes. Free, instant, in-browser time difference calculator.
Temperature Converter
Convert temperatures between Celsius, Fahrenheit and Kelvin instantly. Free, in-browser temperature converter.
Aspect Ratio Calculator
Calculate a missing width or height that keeps your aspect ratio (16:9, 4:3, etc.). Free, instant aspect ratio calculator.
Calorie / TDEE Calculator
Estimate your daily calorie needs (BMR and TDEE) from age, sex, height, weight and activity level. Free, instant.
Unit Converter
Convert between units of length, weight, temperature, volume, area and speed. Free, instant, in-browser unit converter.
Date Calculator (Add / Subtract Days)
Add or subtract days, weeks, months or years from a date to find the resulting date. Free, instant date calculator.
Markup & Margin Calculator
Calculate selling price, profit, markup % and margin % from cost and price. Free, instant business calculator.
Salary to Hourly Converter
Convert an annual salary to hourly, daily, weekly and monthly pay (and back). Free, instant pay converter.
Dice Roller & Random Picker
Roll virtual dice or pick a random item from a list, using the secure crypto API. Free, instant, in-browser.
Stopwatch & Timer
A free online stopwatch with laps and a countdown timer with an alarm. Runs in your browser, no sign-up.
SIP Calculator
Calculate the future value of a monthly SIP (Systematic Investment Plan) for free — see invested amount, estimated returns and total value.
FD Calculator
Calculate fixed deposit maturity and interest for free — enter amount, rate, term and compounding frequency. Instant and private.
Invoice Generator
Create and download a professional invoice PDF for free. Add line items, tax/GST and your currency (incl. ₹) — built in your browser, no upload, no sign-up.
Crypto Profit Calculator
Calculate your crypto profit, ROI and total value from buy and sell prices. Free, instant crypto investment calculator — runs in your browser, no sign-up.
Satoshi to BTC Converter
Convert between Bitcoin (BTC) and satoshis instantly. Also converts to USD, EUR and other fiat with the current price. Free, in-browser, no sign-up.
Mortgage Calculator
Calculate your monthly mortgage payment, total interest and amortisation schedule for any loan amount, rate and term. Free, instant, in-browser.
Time Zone Converter
Convert times between time zones instantly. See what time it is in New York, London, Tokyo, Sydney and 30+ cities worldwide. Free, in-browser, no sign-up.
Days Until Calculator
Calculate how many days, weeks, months and hours until (or since) a specific date. Free, instant countdown calculator.
List Randomizer / Decision Picker
Randomize a list of items, pick a random winner or make a random decision. Paste any list and shuffle, pick or sort — free, in-browser, uses secure crypto API.
Decimal to Fraction Converter
Convert any decimal number to a fraction in simplest form instantly. Handles repeating decimals, mixed numbers and improper fractions — free, in-browser.
Body Fat Calculator (Navy Method)
Calculate your body fat percentage using the US Navy method from simple measurements. Free, private, in-browser.
Ovulation & Due Date Calculator
Calculate your fertile window, ovulation date and estimated due date. Free, private, in-browser.
Period Calculator
Predict your next periods and fertile windows on a calendar. Free, private period tracker that runs in your browser.
Pregnancy Week Calculator
Find out how many weeks pregnant you are, your trimester and days to your due date. Free, private, in-browser.
Conception Date Calculator
Estimate when you conceived from your due date or last period. Free, private conception date estimator in your browser.
Pregnancy Weight Gain Calculator
See your recommended pregnancy weight gain range by week based on pre-pregnancy BMI (IOM guidelines). Free, private, in-browser.
Ideal Weight Calculator
Find your ideal body weight for your height using the Devine, Robinson, Miller and Hamwi formulas plus a healthy BMI range. Free, in-browser.
Child Height Predictor
Predict your child's adult height from the parents' heights using the mid-parental method. Free, private, in-browser.
Chinese Gender Predictor
See what the traditional Chinese gender chart predicts from your lunar age and conception month. For fun — runs in your browser.
Menstrual Cycle Calculator
See what day of your cycle you're on today, your current phase and days to your next period. Free, private, in-browser.
Fuel Cost Calculator
Calculate the fuel cost for any road trip. Enter distance, fuel efficiency and price per litre or gallon. Free, instant, in-browser.
Pomodoro Timer (Focus Timer)
A free Pomodoro timer for focused work: 25-minute focus with 5-minute breaks. Customizable durations. Runs in your browser.
Sleep Calculator (Bedtime Optimizer)
Find the best time to go to bed based on when you need to wake. Optimized for 90-minute sleep cycles. Free, private, in-browser.
Grade Calculator (Final Exam)
Calculate your current grade and what you need on the final exam. Weighted and points-based. Free, instant, in-browser.
Shipping Cost Calculator
Estimate shipping costs by weight and dimensions. Compare USPS, UPS, FedEx and DHL rates. Free, instant, in-browser.
Dog Age Calculator (Dog Years)
Convert your dog's age to human years using the latest veterinary formula. Free, instant, in-browser — works for all breeds and sizes.
Cat Age Calculator (Cat Years)
Convert your cat's age to human years. Free, instant, in-browser — works for kittens and senior cats.
Bra Size Calculator
Calculate your bra size from underbust and bust measurements. Find band size, cup size and sister sizes. Free, private, in-browser.
Ring Size Calculator
Find your ring size from finger circumference or diameter. Supports US, UK, EU and JP sizing systems. Free, instant, in-browser.
Pregnancy Due Date Calculator
Calculate your estimated due date from your last period or conception date, plus gestational age and trimester dates. Free, instant, in-browser.
Daily Water Intake Calculator
Calculate how much water you should drink per day from your weight, activity level and climate. Liters, ounces and glasses. Free, instant, in-browser.
PayPal Fee Calculator
Calculate PayPal fees on any payment — see the fee, what you'll receive, or how much to request to net a target amount. Free, instant, in-browser.
Scientific Calculator
Free scientific calculator online with trig, logarithms, powers, roots, factorials and a DEG/RAD toggle. Instant results, right in your browser.
Fraction Calculator
Add, subtract, multiply and divide fractions and mixed numbers. See the simplified result, mixed number and decimal with worked steps. Free and instant.
Countdown Timer
A free online countdown timer with hours, minutes and seconds, quick presets and an alarm at zero. Pause, resume and reset — runs in your browser, no sign-up.
Rent Receipt Generator
Generate rent receipts for HRA claims free — fill tenant, landlord and rent details, get print-ready monthly receipts with revenue stamp space.
Which calculators tool should I use?
- Work out a percentage → Percentage Calculator
- Estimate a loan repayment (EMI) → Loan / EMI Calculator
- Project savings with compound interest → Compound Interest Calculator
- Check your BMI → BMI Calculator
- Split a bill and tip → Tip Calculator
About these calculators
Quick, accurate calculators for money, health, dates and everyday math — percentages, discounts, loan EMIs, compound interest, BMI and calories, tips, GPA, age and date differences, and more. Each shows its result instantly as you type, runs in your browser, and stores nothing. Pick a tool above to get started, or browse the full A–Z index.
Frequently asked questions
Are the calculators free and private?
Yes — every calculator is free, needs no sign-up, and runs entirely in your browser.
Should I rely on these for financial or medical decisions?
They're accurate estimates for everyday use, but not a substitute for professional financial or medical advice.
Do results update as I type?
Yes — results recalculate instantly as you change the inputs.