Five everyday calculators in one: percentage, tip, discount, loan/EMI and BMI — fast, accurate and right in your browser.
🔒 Every calculation runs on your device — nothing is sent anywhere.
Find X% of a number, what percent one value is of another, or the percent change between two numbers.
Tip presets and instant per-person totals make splitting the check painless.
Estimate monthly loan/EMI payments and total interest, and check your BMI in metric or imperial.
Most disputes about a calculator's answer come down to precedence rather than arithmetic. Multiplication and division bind more tightly than addition and subtraction, and operators of equal precedence evaluate left to right — so 10 − 3 − 2 is 5, not 9.
The genuinely ambiguous case is implicit multiplication. Expressions of the form 6 ÷ 2(1+2) circulate periodically as viral arguments, and the honest answer is that there is no universal convention: some calculators treat juxtaposition as binding tighter than division and return 1, others treat it as ordinary multiplication and return 9. Both are internally consistent. The lesson is not that one camp is wrong but that the expression is badly written — parentheses cost nothing and remove the ambiguity entirely.
Percentage keys are the other inconsistency. On many calculators 200 + 10% yields 220, because the percent key is interpreted relative to the preceding term, while on others it yields 200.1. Check what your tool does with a case you can verify mentally before trusting it on one you cannot.
Calculations here use IEEE 754 double precision, which stores numbers in binary. Most decimal fractions have no exact binary representation, so 0.1 + 0.2 produces 0.30000000000000004 rather than 0.3 — not a fault, but a consequence of the format, and the same behaviour you will find in essentially every programming language and spreadsheet.
Displayed results are rounded to hide this, which is the right default but means the stored value can differ slightly from what you see. It matters when a result feeds into another calculation: rounding at each step and then multiplying compounds the error, whereas keeping full precision throughout and rounding once at the end does not.
Integers are exact up to 2⁵³, about 9.007 × 10¹⁵. Beyond that, consecutive integers are no longer all representable, so very large values silently round. For money, this is why financial systems generally store amounts as integer minor units — pence or cents — rather than as decimal fractions.
There is more than one correct way to round, and the choice has real consequences. Round-half-up, the method taught in schools, always sends .5 upward, which introduces a small systematic upward bias across many values. Round-half-to-even — banker's rounding — sends .5 to the nearest even digit, so 2.5 becomes 2 and 3.5 becomes 4, and the bias cancels over a large set.
That is why banker's rounding is the default in many financial and statistical systems, and it is the IEEE 754 default too. If you compare a total computed in one system against the same total in another and find a discrepancy of a few pence across thousands of rows, differing rounding modes are a likely explanation.
For money specifically, round once at the end rather than at each intermediate step, and be explicit about the method where it matters. Percentages compound the issue: three values rounded individually to whole percentages frequently sum to 99 or 101 rather than 100, which is expected rather than a mistake.
On the Percentage tab you can find X% of a number, work out what percent one number is of another, or calculate the percent increase or decrease between two values.
Enter the bill, a tip percentage (or tap a preset) and the number of people — you'll see the tip, the total and each person's share.
From the loan amount, annual rate and term, using the standard amortization formula, to show monthly payment, total interest and total repaid.
Weight in kilograms divided by height in metres squared. Metric and imperial units are supported, with your category and a healthy weight range.
Because implicit multiplication has no universal precedence convention — some tools bind it tighter than division and give 1, others treat it as ordinary multiplication and give 9. The expression is ambiguous as written; parentheses resolve it.
Binary floating point cannot represent most decimal fractions exactly. The result is 0.30000000000000004, and the same happens in nearly every programming language and spreadsheet.