Plastic Bottle Waste Calculator
Turn your weekly bottled-water habit into kilograms of plastic and CO₂ per year.
Result
Bottles per year
520
Plastic (kg/year)
10.4
CO₂ (kg/year)
31.2
How it works
A PET water bottle weighs about 20 g in the 0.5 L format and about 35 g in the 1.5 L format. Multiply your weekly count by 52 and by the bottle weight, and the innocent-looking habit becomes a yearly mass: ten small bottles a week is 520 bottles and roughly 10 kg of plastic per year. Producing, transporting and disposing of PET emits in the order of 3 kg of CO₂ per kg of plastic — so those same ten bottles a week carry about 31 kg of CO₂ annually, before counting the bottled water’s transport. Only part of the world’s plastic bottles are collected for recycling, and PET fibres degrade with each cycle (downcycling). A reusable bottle — with tap, filtered or larger-format water — removes this entire line from your footprint at almost no cost.
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Frequently asked questions
Is recycling bottles enough?
It helps, but collection rates are partial and PET quality drops with each cycle. Reducing the number of single-use bottles beats recycling them.
How long does a plastic bottle persist in nature?
Commonly cited estimates are around 450 years for a PET bottle to break down — and it fragments into microplastics along the way rather than disappearing.
What is the cheapest alternative?
A reusable bottle filled with tap water (filtered if needed) or large-format containers. The habit typically pays for the bottle within weeks.
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