Sustainability calculators & tools
Quick, free calculators that turn vague good intentions into real numbers. Each one runs entirely in your browser — nothing you enter is sent anywhere or stored — and comes with practical tips to improve the result.
Food waste calculator
See roughly what your household throws away in uneaten food each year — and how much you could save by wasting less.
Try the calculatorReusable swap savings calculator
Compare a reusable against single-use to see your yearly saving and how fast it pays for itself.
Try the calculatorAppliance energy cost calculator
Work out what any appliance costs to run per year using your own electricity rate — including standby power.
Try the calculatorHome water use calculator
Estimate your household's daily and yearly water use, see where it goes, and find the biggest savings.
Try the calculatorPrivate by design
Every calculator here runs locally in your browser using plain JavaScript. The numbers you type are used only to show your result on the page — they're never uploaded, saved or shared. Close the tab and they're gone. The figures are deliberately transparent: where a calculation needs a rate or price, you enter your own, so the maths reflects your real situation rather than a guessed average.
These tools are for guidance and motivation, not precision to the penny. Their job is to make an invisible cost — wasted food, standby power, water down the drain — visible enough that a small habit feels worth starting. Pair each one with the linked guide and you'll have both the number and the plan.
Popular guides
Numbers are motivating — habits are the win
Run a calculator, pick the biggest number, and start one change this week. Then explore the guides to keep the savings coming.