Free Online Calculators
Accurate, fast, and free calculator tools for finance, health, education, and everyday math — no signups, no popups, no ads blocking your results.
Welcome to the BSM Sites calculator library. Every calculator on this page is built from scratch using industry-standard formulas, verified against trusted sources, and tested on mobile, tablet, and desktop. Whether you’re planning a home purchase, comparing loan offers, tracking your health metrics, or solving a math problem — you’ll find a clean, fast, and accurate tool here.
Unlike most calculator websites, we don’t bury results under banner ads, force you to register, or hide premium features behind paywalls. Every tool is fully free to use, works instantly, and shows you the formula behind the calculation so you understand the result — not just the number.
Finance Calculators
Finance Calculators
Plan smarter with calculators built for real financial decisions — mortgages, loans, investments, and savings. All calculations include detailed breakdowns and downloadable schedules where applicable.
Mortgage Calculator
Estimate your monthly home loan payment with a full amortization breakdown. Supports U.S. 30-year and 15-year fixed loans plus custom terms.
Mortgage Payment Calculator
Calculate your exact monthly mortgage payment, principal, interest, property taxes, and insurance with a full amortization schedule.
Loan EMI Calculator
Calculate the monthly EMI on any loan, personal, car, education, or business. Enter your amount, rate, and term to see your payment instantly. Supports 20+ currencies worldwide.
Compound Interest Calculator
Calculate compound interest on savings, investments, and loans. See how your money grows over time with daily, monthly, or yearly compounding. Supports 150+ currencies worldwide.
Debt Payoff Calculator
Pay off credit cards, loans & debt faster. Compare Avalanche vs Snowball strategies, see your debt-free date, and find out exactly how much interest you'll save.
Retirement Calculator
Find out exactly how much you need to retire comfortably. Calculate your retirement savings goal, monthly contribution needed, and projected nest egg.
Paycheck Calculator
Calculate your exact take-home pay after taxes in seconds. Supports salary & hourly workers, all pay frequencies, pre-tax deductions
Percentage Calculator
Calculate any percentage instantly. Find what is X% of Y, X is what percent of Y, percentage increase, decrease, difference, or change
Tip Calculator
Calculate tips instantly, split the bill between any number of people, and choose from 25+ currencies. Perfect for restaurants, taxis, delivery, hotels, and salons — worldwide.
Discount Calculator
Calculate sale price, total savings, and your real out-the-door price in seconds. Handles stacked & double discounts, reverse discounts (find the original price), sales tax / VAT, and 25+ currencies — worldwide.
Sales Tax Calculator
Add sales tax to a price, remove it to find the original pre-tax amount, or work out the tax rate from a before-and-after price.
Loan Calculator
Calculate your monthly loan payment, total interest, and total cost for any loan — personal, auto, student, or business.
Rent vs Buy Calculator
Should you rent or buy a home? Compare the true, all-in cost of each over time — mortgage, taxes, maintenance, rent increases, equity build-up, and the opportunity cost of your down payment.
Salary Calculator
Convert your pay between hourly, daily, weekly, biweekly, semi-monthly, monthly, quarterly, and yearly in seconds. Enter any one figure and instantly see all the others
Net Worth Calculator
Find out exactly what you're worth. Add up everything you own — cash, savings, investments, retirement, your home and car — then subtract what you owe.
Salary Raise Calculator
How much is your pay raise really worth? Enter your current salary and either the percentage raise or your new salary, and instantly see your new pay, the increase as a percentage, and exactly how much extra you'll earn per year, month, week, and hour. Works in any currency.
VAT & GST Calculator
Add VAT or GST to a price, or remove it from a tax-inclusive total (reverse VAT) — in seconds. Enter any rate and currency, and see the net amount, the tax, and the gross total clearly broken down.
Health & Fitness Calculators
Track your health metrics with calculators using formulas from peer-reviewed medical and fitness research. Note: these tools provide general estimates and should not replace medical advice.
BMI Calculator
Calculate your Body Mass Index (BMI) instantly in metric or imperial units. Free, accurate, and worldwide
Calorie Calculator
Calculate your daily calorie needs, BMR, TDEE and macros for weight loss, maintenance or muscle gain.
TDEE Calculator
Calculate your Total Daily Energy Expenditure (TDEE) and BMR instantly. Find your exact maintenance, weight loss, and weight gain calorie targets
Pregnancy Due Date Calculator
Estimate your baby's due date, current pregnancy week, trimester, and key milestones. Calculate by last menstrual period (LMP), conception date, ultrasound, or IVF transfer date. Works worldwide.
Ovulation Calculator
Predict your ovulation day, fertile window, and next period in seconds. See a color-coded calendar of your most fertile days over the next 6 cycles.
BMR Calculator
Find your Basal Metabolic Rate — the calories your body burns at complete rest — using three trusted formulas: Mifflin-St Jeor, Harris-Benedict, and Katch-McArdle.
Macro Calculator
Get your daily protein, carbs, and fat targets — in grams, calories, and percentages — for weight loss, muscle gain, maintenance, or keto.
Pace Calculator
Find your running pace, predict your race finish time, or work out the distance you can cover at a given pace — for 5K, 10K, half marathon, marathon, ultra, or any custom distance.
Body Fat Calculator
Estimate your body fat percentage in seconds using the trusted U.S. Navy tape method or a quick BMI-based estimate.
Water Intake Calculator
How much water should you drink a day? Get your personalized daily hydration target based on your body weight, activity level, and climate. See it in liters, milliliters, cups, and ounces — and find out how many glasses that really means.
Sleep Calculator
What time should you go to bed — or wake up? This sleep calculator uses 90-minute sleep cycles to find the times that let you wake up between cycles, not in the middle of one, so you rise refreshed instead of groggy.
Education Calculators
Advanced education calculators to simplify academic calculations like GPA, percentages, grades, and study planning.
Get accurate results instantly to track performance, improve scores, and stay on top of your academic goals.
GPA Calculator
Calculate your Grade Point Average (GPA) for high school, college, or university. Supports 4.0, 4.3, 5.0, 10.0 (CGPA India), and percentage grading scales used worldwide.
Grade Calculator
Find your current weighted grade, the exact score you need on your final exam, or your full semester grade — in seconds.
Game Calculators
Specialized calculators for popular games. Built and verified by players, updated when game mechanics change.
Palworld Breeding Calculator
Select two Pals to instantly predict their offspring — including all possible passives and traits. Plan your perfect breeding chain.
Dice Probability Calculator
Work out the odds of any dice roll. Enter standard dice notation like 2d6+3 or 4d8 and instantly see the chance of hitting a target, the full probability distribution, the average, and the min and max. Perfect for D&D, board games, and any tabletop RPG.
Everyday Tools
Smart everyday tools to simplify daily calculations, conversions, and quick problem-solving with speed and accuracy.
From unit converters to practical utilities, get instant results designed for convenience and efficiency.
Age Calculator
Find your exact age from your date of birth in years, months, weeks, days, hours, minutes, and seconds.
Date Calculator
Find the exact number of days, weeks, months, and years between two dates, add or subtract time from any date, or count down the days until a future date.
Hours Calculator
Work out the time between two times, total your work hours with lunch breaks and overtime, or fill in a full weekly time card.
Fuel Cost Calculator
Work out exactly what a trip will cost in fuel. Enter your distance, your vehicle's fuel efficiency, and the price of fuel — and get the total gas/petrol cost, fuel needed, cost per mile or km, and the cost split between passengers.
Square Footage Calculator
Calculate the area of any room or space in square feet and square meters at once. Add multiple rooms, handle rectangle, circle, and triangle shapes, allow for waste, and estimate flooring, paint, or tile cost.
Time Calculator
Add or subtract hours, minutes, and seconds, find the duration between two times, multiply or divide a time value, and convert between time units.
Concrete Calculator
Find out exactly how much concrete you need for a slab, footing, wall, round column, or set of stairs — in cubic yards, cubic metres, bags, or ready-mix.
Dice Probability Calculator
Work out the odds of any dice roll. Enter standard dice notation like 2d6+3 or 4d8 and instantly see the chance of hitting a target, the full probability distribution, the average, and the min and max. Perfect for D&D, board games, and any tabletop RPG.
Age Difference Calculator
Find the exact age gap between two people. Enter two birth dates and instantly see who is older and by how much — in years, months, weeks, and days.
Dog Age Calculator
How old is your dog in human years? Forget the old "multiply by 7" myth — this dog age calculator uses the modern, size-adjusted veterinary method (and an optional scientific formula) to convert dog years to human years accurately.
Cat Age Calculator
How old is your cat in human years? Skip the old "multiply by 7" myth — this cat age calculator uses the modern veterinary method to convert cat years to human years accurately.
Every calculator shows the exact formula it uses. Mortgage calculations follow industry-standard amortization formulas. Health calculators use peer-reviewed research equations. Tax calculators use current published rates.
You shouldn’t need an account to calculate a percentage. Every tool works instantly the moment the page loads.
Real responsive design, not a desktop site squeezed onto a phone screen. Tested on iPhone, Android, iPad, and desktop browsers.
Every calculator includes the formula, examples of how the calculation works, and answers to common questions about the topic.
We don’t store your inputs. We don’t track what you calculate. Your data stays in your browser.
BSM Sites is a WordPress development agency. We build these tools to showcase what custom WordPress development looks like — and we keep them maintained because we use them in client work too.
We build custom calculator tools, quote generators, and interactive widgets as part of our WordPress development services — the same way we build the free ones on this page. If you need a custom tool for your website, tell us what you need and we’ll send a fixed-price quote within 48 hours.
BSM Sites maintains one of the most accessible free online calculator libraries on the web. Every tool is built using industry-standard formulas, tested across devices, and updated regularly. Our finance calculators (mortgage, loan EMI, compound interest, retirement) help with real financial decisions. Our health calculators (BMI, TDEE, calorie tracking) use peer-reviewed research formulas. Our education calculators (GPA, grade calculator) support both U.S. and international grading systems. And our specialty calculators (Palworld breeding, gaming tools) serve communities the big calculator sites ignore.
The library is built and maintained by BSM Sites, a WordPress development agency that creates custom calculator tools and interactive widgets for client websites. Every calculator on this page is also a working example of what we can build for your business. If you need a custom calculator, quote tool, or interactive widget for your site, get in touch — most projects are quoted within 48 hours.