Free Online Calculators
Every calculator here runs in your browser and shows the formula it used, so you can check the maths yourself. Nothing you type is uploaded, and there is no signup or download.
All Calculators (29 Available)
Age Calculator
Find your exact age in years, months, days, hours and minutes.
Percentage Calculator
Solve every common percentage question in one place.
Percentage Increase Calculator
Work out the percentage rise between two values.
Percentage Decrease Calculator
Work out the percentage drop between two values.
Discount Calculator
Find the sale price, the amount saved and the real discount.
Profit Margin Calculator
Calculate margin, markup and the price you need to charge.
Profit and Loss Calculator
Work out profit or loss and the percentage on any transaction.
GST Calculator
Add or remove GST at any rate, with the CGST/SGST/IGST split.
Sales Tax Calculator
Add or remove sales tax, VAT or any percentage tax.
Salary Calculator
Convert a wage between hourly, weekly, monthly and yearly.
EMI Calculator
Monthly instalment, total interest and full amortisation schedule.
Loan Calculator
Compare loan payments, total interest and payoff timelines.
Simple Interest Calculator
Calculate simple interest with the classic P × R × T formula.
Compound Interest Calculator
See how savings grow with compounding and regular contributions.
SIP Calculator
Project the value of a monthly systematic investment plan.
Investment Calculator
Project the future value of a lump sum investment.
ROI Calculator
Return on investment as a percentage, plus annualised return.
Mortgage Calculator
Monthly payment including tax and insurance, plus full amortisation.
Tip Calculator
Split a bill and work out the tip, per person, in seconds.
BMI Calculator
Body mass index in metric or imperial, with the healthy range.
BMR Calculator
Basal metabolic rate — the calories you burn at complete rest.
Calorie Calculator
Daily calorie needs for maintenance, loss and gain.
Date Difference Calculator
Days, weeks, months and years between any two dates.
Hours Calculator
Add up worked hours and convert them to decimal for payroll.
Average Calculator
Mean, sum and count from any list of numbers.
Mean, Median and Mode Calculator
All three measures of central tendency from one data set.
Standard Deviation Calculator
Population and sample standard deviation, variance and more.
Fraction Calculator
Add, subtract, multiply and divide fractions with the steps shown.
Ratio Calculator
Simplify ratios, scale them up and solve for a missing value.
About Calculators
The finance calculators cover the numbers people actually need to decide something: monthly loan instalments, the real cost of a discount, GST added or removed from an invoice, and how much a SIP or lump-sum investment could grow to at a given rate.
The health and body calculators use published formulas — Mifflin-St Jeor for BMR, the standard WHO weight-for-height ranges for BMI — and name the formula on the page so you know exactly what produced the number.
The date and statistics calculators handle the fiddly parts for you: leap years, month-end rollover, timezone-free date arithmetic, and population versus sample standard deviation.
Calculators FAQs
Are these calculators free to use?
Yes. Every calculator on this site is free, needs no account, and has no usage limit. They are funded by advertising on the page.
Is my data sent to a server?
No. All calculators run entirely in your browser using JavaScript. The numbers you type never leave your device, which is why the results appear instantly.
How accurate are the results?
The arithmetic is exact to JavaScript double precision, and money values are rounded only at the final display step. Each calculator states the formula it uses so you can verify it independently.
Can I use these calculators on a phone?
Yes. Every calculator is built mobile-first with large touch targets, numeric keyboards on number fields, and a single-column layout on small screens.