Formula
- Use the units shown beside each field.
- Results update automatically whenever you change an input.
- Displayed values use up to four decimal places, or scientific notation for very small or large numbers. Calculations use standard floating-point arithmetic; exact integer and fraction tools identify their own precision rules.
- Costs only. Water potability and whether filtration is needed are not assessed; fixed filter cost is charged for the entered scenario.
Example Calculation
- Water consumed: 2 L/day
- Days: 365
- Bottled price: 0.5 currency/L
- Tap water tariff: 3 currency/m³
- Annual filter cost: 30 currency
730 L costs 365 bottled versus 32.19 for the entered tap tariff and filter, a difference of 332.81.
Frequently asked questions
How do I use this calculator?
Enter water consumed, days, bottled price, tap water tariff, annual filter cost. The result updates automatically. Use Reset to restore the example values.
What method does it use?
bottled=liters × price/L; tap=liters/1000 × tariff+filter cost.. Costs only. Water potability and whether filtration is needed are not assessed; fixed filter cost is charged for the entered scenario.
Why might a rounded result differ?
The calculation keeps full numeric precision internally, then rounds the displayed result. Rounding intermediate steps by hand can produce a slightly different answer.
Are my inputs saved online?
No. This calculator processes your inputs in your browser. A recently used list stores only calculator names on this device, not your entered values.
Check the assumptions and units before using this result. Read about calculation methods.