Utilities

Calculate exact age in years, months, and days from a birth date — leap-year aware.

Calculate days between two dates with a years, months, and days breakdown.

Convert one civil date and time across IANA zones, with UTC offsets and a DST-change hint — privately in your browser.

Convert Unix seconds and milliseconds to UTC, local, and IANA time zones — plus ISO-8601, RFC 2822, and relative time. Runs in your browser.

Count weekdays between two dates, skip custom holidays, or add working days. Saturday–Sunday, Friday–Saturday, and Sunday-only weekends.

Estimate body surface area (m²) with the Mosteller formula from height and weight.

Calculate prescription days supply from quantity dispensed, dose amount, and doses per day.

Use C₁V₁ = C₂V₂ to find how much stock and diluent you need for a target concentration and volume.

Calculate a weight-based drug dose (mg/kg) and daily total from patient weight and frequency.

Calculate IV pump rate (mL/hr) and gravity drip rate (gtt/min) from volume, time, and drop factor.

Convert an ordered mg dose into mL using the liquid’s concentration (mg/mL).

Estimate pediatric doses with Clark's rule, Young's rule, or mg/kg weight-based dosing.