What is a plastic footprint?
Your plastic footprint is the total mass of plastic you consume and discard over a year. Single-use items like water bottles, shopping bags, coffee cups, food containers, straws and packaging add up quickly. This calculator turns your weekly habits into an annual estimate in kilograms so you can see where the biggest savings are.
How to use it
Enter roughly how many of each plastic item you use in a typical week. The tool multiplies each count by a representative per-item weight, adds them together to get your weekly plastic mass, then multiplies by 52 weeks to give your yearly total. Adjust the numbers to test the impact of switching to reusables.
The formula explained
The calculation is simply \( P = 52 \times \Sigma(\text{count} \times \text{weight}) \). Each item type has a typical weight: bottle 10 g, bag 6 g, cup/lid 12 g, food container 30 g, straw/cutlery 1.5 g, and wrap/packaging 4 g. Each weekly count is multiplied by its weight in kilograms, the products are summed for a weekly figure, and that figure is scaled to a full year.
$$\text{Annual Plastic} = 52 \times \left( \begin{aligned} &0.010\,\text{Bottles} + 0.006\,\text{Bags} + 0.012\,\text{Cups} \\ &+\ 0.030\,\text{Containers} + 0.0015\,\text{Straws} + 0.004\,\text{Wrap} \end{aligned} \right)$$
Worked example
Suppose you use 7 bottles, 5 bags, 3 cups, 4 containers, 5 straws and 6 wrap items per week. Weekly mass =
$$7\times0.010 + 5\times0.006 + 3\times0.012 + 4\times0.030 + 5\times0.0015 + 6\times0.004 = 0.070 + 0.030 + 0.036 + 0.120 + 0.0075 + 0.024 = 0.2875\ \text{kg}$$Annual = \( 0.2875 \times 52 \approx 14.95 \) kg of plastic per year.
FAQ
Are the item weights exact? No — they are typical averages. Actual weights vary by brand and product, so treat the result as an estimate.
Does this include recycling? No. It estimates plastic consumed regardless of how it is disposed; recycling reduces landfill but not the original footprint.
How can I lower my footprint? Reusable bottles, bags and cups usually cut the largest contributors quickly. Re-run the calculator with reduced counts to quantify the saving.
