Calculate
Everyday Calculators
BMI, loan payments, percentages and date differences — with the formulas shown and nothing leaving your browser.
BMI calculator
Runs locallyYour BMI
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Loan calculator
Runs locallyMonthly payment
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First 12 payments
| Month | Principal | Interest | Balance |
|---|
Percentage calculators
Percent of a number
Result: —
What percent is one number of another
Result: —
Percentage change
Change: —
Date difference
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About this tool
This page groups four calculators that are useful every week. Body mass index uses the standard WHO bands; the loan calculator uses the annuity formula and lists the first twelve amortization rows; percentages cover “percent of”, “what percent” and percentage change; the date tool counts days, weeks and weekday-only working days.
Every field updates as you type. There is no submit button and no network request, and the formulas are described next to each result so you can check the arithmetic yourself.
How to use it
- BMIEnter height and weight in metric or imperial units. The result includes the WHO category and the healthy weight range for that height.
- Loan paymentEnter the principal, annual rate and term in months. You get the monthly payment, total interest, total repayment and a first-year schedule.
- Percentages and datesUse the three percentage blocks for common comparisons, and pick two dates to see the exact gap in days, weeks and working days.
Common questions
Is BMI a diagnosis?
No. BMI is a screening indicator. Muscle mass, age, pregnancy and ethnicity all affect its interpretation; consult a clinician for medical advice.
How is the monthly payment calculated?
It uses the standard annuity formula: P × r / (1 − (1 + r)⁻ⁿ), where r is the monthly rate and n the number of months. A 0% rate falls back to principal divided by months.
How are working days counted?
Weekdays from Monday to Friday are counted between the two dates, excluding the start date. Public holidays are not subtracted.