Practical calculators that actually explain things.
Free calculators for everyday needs — GST, percentages, mortgage repayments, fitness targets, and more. Every calculator includes explanations of how the math works, what the results mean, and common use cases. No account needed. No data stored.
Finance
GST Calculator
Add or remove 10% Australian GST. Instantly calculate GST-exclusive and GST-inclusive prices.
Percentage Calculator
Find percentages, calculate percentage change, and work out what percent one number is of another.
Tip Calculator
Calculate the right tip based on service quality. Split bills fairly among any number of people.
Savings Goal Calculator
See how long it takes to reach your savings goal with a target amount, monthly savings, and expected interest rate.
Investment Calculator
Project portfolio growth over time with compound returns, regular contributions, and inflation adjustments.
Compound Interest Calculator
See how compound interest grows wealth over time. Compare different rates, terms, and contribution amounts.
Mortgage Calculator
Calculate Australian home loan repayments. See the true cost including LMI, interest, and extra repayment scenarios.
Loan Calculator
Calculate personal loan and car loan repayments. See the true cost with Australian comparison rates.
Retirement Calculator
Estimate your retirement savings trajectory. See how long your nest egg will last in retirement.
Debt Pay-off Calculator
Find the fastest way to become debt-free. Compare snowball vs avalanche strategies for any debt type.
Maths
Fraction Calculator
Add, subtract, multiply, and divide fractions. Convert between fractions, decimals, and percentages instantly.
Unit Converter
Convert between units of length, weight, temperature, speed, volume, and more. All common conversions in one place.
Speed Calculator
Convert between speed units (km/h, mph, m/s, knots). Calculate speed, distance, or time from the other two values.
Discount Calculator
Calculate sale prices and savings. Apply single or stacked discounts to see the final price.
Health
BMI Calculator
Calculate your Body Mass Index and see how you compare to standard weight status categories.
Calorie Calculator
Calculate your daily calorie needs based on your age, weight, height, and activity level. Supports weight loss, maintenance, and muscle gain goals.
Ideal Weight Calculator
Find your ideal body weight based on height using the Devine, BMI, and Robinson formulas.
Body Fat Calculator
Estimate body fat percentage using the US Navy method. See how you compare to typical body fat ranges.
Pregnancy Due Date Calculator
Calculate your expected due date based on last menstrual period or conception date.
Ovulation Calculator
Estimate your ovulation window and fertile days based on your average cycle length.
Sleep Calculator
Find the best time to wake up or go to sleep based on 90-minute sleep cycles for maximum rest.
Sports & Fitness
1RM Calculator
Estimate your one-rep max from any weight and reps. Get percentages for warm-up sets and training loads.
Heart Rate Zone Calculator
Find your target heart rate zones for fat burn, cardio, and peak performance training.
Race Splits Calculator
Split a race time into equal pace segments. See projected split times for any distance.
Running Pace Calculator
Convert between pace per km and speed. Calculate race finish times from pace or pace from target time.
Time
Utilities & Transport
Carbon Footprint Calculator
Estimate your annual carbon footprint from transport, home energy, and diet. See how you compare to global averages.
Electricity Cost Calculator
Calculate the cost of running any appliance. Enter wattage, usage hours, and your electricity rate.
Fuel Calculator
Calculate fuel economy in L/100km or mpg. Estimate trip fuel cost based on distance and consumption.
EV Charging Calculator
Compare home vs public charging costs. Calculate cost per kilometre and charge time for any EV.
Why use our calculators?
⚡ Instant Results
No submit buttons. No page reloads. Results appear as you type, every time.
🔒 Privacy First
No accounts. No tracking. No data collected. Your calculations stay on your device.
🎯 No Signup Required
Open the page and start calculating. No account, no email, no friction.
🌍 Works Everywhere
Fully responsive. Use it on your phone, tablet or desktop. No app to install.