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Independent, evidence-based water education · Reviewed for 2026

Bottled vs Tap · Tool

Water Cost Calculator

Compare the yearly cost of buying bottled water with the equivalent volume from your tap — currency-neutral, so it works anywhere in the world.

4.8 (212) Free & private — runs in your browser
Default 0.002 — adjust to your local tariff.

Currency-neutral — enter any currency and the result is in the same unit. Figures are estimates for educational comparison only.

Educational estimates only — not medical, engineering or professional advice.

Bottled water costs many hundreds of times more per litre than tap water in most developed countries. This calculator puts your personal habit into numbers so you can see exactly what the difference means over a year.

All inputs are currency-neutral — enter any unit and the result is in the same unit. Adjust the tap price to match your local water tariff for the most accurate comparison.

How to use this tool

Fill in four quick values:

  • Bottles per day — your typical daily habit. You can enter decimals (e.g. 0.5 for one bottle every two days).
  • Price per bottle — the retail price you usually pay.
  • Bottle size — the volume in mL (commonly 500 mL or 1,000 mL).
  • Tap price per litre — check your water bill or use the default of 0.002, which is a typical figure for UK tap water.

A little background

The gap between bottled and tap water cost is striking in most regions. The calculation assumes the tap water you would drink is safe and palatable, which is true in most high-income countries. If you are filtering tap water, add the cost of filter replacements to the tap-water side for a fair comparison.

For a broader environmental perspective, see our guide on bottled water versus tap water.

Tool FAQ

In most high-income countries tap water is subject to strict regulation and is safe to drink. Our bottled water vs tap water guide examines the evidence in detail.

It varies widely. In the UK it is roughly 0.1–0.2 pence per litre (about 0.001–0.002 GBP). In the US it is around USD 0.002 per litre. Check your water utility bill for the exact figure.

Yes, for a fair comparison include the amortised cost of filter cartridges if you use one. Even with a good filter the total is typically far below bottled-water costs.

No — this calculator shows financial cost only. The environmental impact of producing and transporting plastic bottles is an additional consideration covered in our plastic bottles guide.
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