Help — Formulas & assumptions
Explanations are simplified and intended for informational use.
Table of contents
On this page
Loan
The loan calculator estimates amortized payments using a fixed interest rate and a fixed term.
- Principal: the amount you borrow.
- APR: annual percentage rate, converted to a monthly rate.
- Term: number of months you repay over.
Monthly payment depends on the interest rate and the number of payments. Rounding differences between tools are normal.
Informational only. Taxes, fees, insurance, and variable rates are not included.
Age
The age calculator computes a calendar-based difference between your date of birth and an “as of” date.
- Years: full years since your birth date.
- Months: full months after subtracting years.
- Days: remaining days after subtracting years and months.
Informational only. “Age” can be defined differently in different contexts.
BMI
BMI (Body Mass Index) is an estimate based on height and weight.
- Metric: BMI = kg / m²
- Imperial: BMI = 703 × lb / in²
Categories are broad ranges and may not apply equally across all individuals.
Informational only. BMI is a screening metric and does not diagnose health.
Privacy
Calculations run locally in your browser. There are no accounts and no data uploads.
Optional convenience features may store your last inputs in `localStorage` on your device.