Kalkulatory
Procenty, wiek, BMI, losowanie.
Ile to X% z Y?
X to jaki % z Y?
Zmiana procentowa
Napiwek / VAT / rabata
Średnia / liczba / dane
Netto / brutto / VAT
How to use the calculator tools
- Open the tab for the calculation you need: percentage, age, BMI, random numbers, tip, average, or tax.
- Enter the values into the labelled fields, for example a base amount and a percentage.
- Read the result below the fields as you type or after you press the calculate button.
- Switch tabs at any time to move between the different everyday calculators.
- Work with one tab at a time and use the others whenever a follow-up calculation is needed.
What you can calculate
- Work out discounts, VAT and percentage changes on prices.
- Check a person's exact age in years, months and days.
- Estimate body mass index from weight and height.
- Roll random numbers within a range or split a bill with a tip.
- Splitting a restaurant bill with a tip among several people.
Frequently asked questions
Is my data sent to a server?
No. All calculations run directly in your browser and the values never leave your device. Nothing is stored, uploaded, or tracked.
What are the limitations of these calculators?
They provide everyday estimates, so BMI and tax results are informative rather than medical or financial advice. Inputs must be valid numbers, otherwise the result shows a dash.
Can I calculate a percentage increase or decrease?
Yes. The percentage tab offers three modes, including a percentage of a value and the change between two values.
Does the random number tool use a fair generator?
It uses the built-in random generator of your browser for everyday picks such as winners or sample groups. It is not designed for cryptographic or lottery-grade randomness.
Can I work offline?
Yes. The page is a static site and works without a network connection once it is loaded.
Can I calculate an average of several numbers?
Yes. The average tab accepts a list of numbers separated by commas or spaces. It adds the values and divides the sum by the count. This is handy for grades, repeated measurements, or any set of readings. Entries that are not numbers are skipped so the result stays sensible.