Which BMI categories does this use?

The standard World Health Organization ranges: under 18.5 is underweight, 18.5–25 is normal weight, 25–30 is overweight, and 30+ is obese.

Does the days calculator count the start and end date both?

It counts the whole days between the two dates (end minus start), the same way you'd count nights between a check-in and check-out date.

Can I enter a custom tip percentage?

Yes — type any percentage into the custom field next to the preset buttons and it's used immediately.

Is my data stored anywhere?

No — every calculation happens in your browser and nothing is sent to a server.

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Calculator

Metric (kg/cm) Imperial (lb/ft+in)

Height (cm)

Weight (kg)

Underweight Normal weight Overweight Obese

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Everyday Calculators

Four calculators in one place: BMI, days between two dates, percentages, and a tip calculator with bill splitting. Switch between them with the tabs above — no need to visit a separate page for each.

How it works

Each tab uses a standard, verifiable formula: BMI divides weight in kilograms by height in meters squared; the date calculator counts whole calendar days (and separately, weekdays) between two dates; percentage results use plain ratio math (part/whole × 100); and the tip calculator applies your chosen percentage to the bill total, then divides the grand total evenly across the number of people you specify.

Worked example

A $50 bill split three ways with an 18% tip: the tip comes to $9, the total is $59, and each person owes $19.67 — switch to the Tip & Bill Split tab to see this update live as you change any number.

What is X% of Y?

X is what percent of Y?

Percentage change from X to Y

Everyday Calculators

How it works

Worked example

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