The food you throw out does not stop costing the planet once it leaves your kitchen. As it rots in a landfill, it releases methane, a greenhouse gas far stronger than CO2 over the short term. Food waste is a climate problem hiding in plain sight at the bottom of your trash can, and almost no one measures it. This calculator turns the food you bin into a number you can actually picture: kilograms of emissions, and the equivalent miles of driving.
What this calculator does
It estimates the yearly climate cost of the edible food your household sends to the landfill. You give it either your household size or the weight you bin each week, and it returns three things.
- Food wasted per year, in pounds and kilograms.
- Landfill emissions, in kilograms of CO2e, shown as an equivalent number of miles driven.
- What composting instead would save, as a percentage and an absolute figure.
It also flags a larger, less obvious number: the carbon already spent growing and shipping that food before it ever reached your bin. More on that below, because it changes the whole picture.
The output is an estimate built on US averages and federal emission factors. It is not a precise audit of your specific groceries. It is meant to be roughly right and honestly sourced, not falsely exact.
How to use it
The calculator has two input modes. Pick the one that matches how much effort you want to put in.
- By household size. Enter the number of people who live in your home. The tool multiplies that by the US average of 116 kg (256 lb) of edible food wasted per person per year, the consumer-level figure from the EPA's 2025 report. This mode is fast, but it assumes your household is average.
- By the pound. Enter the pounds of food you throw out in a typical week. The tool multiplies that by 52 to get a yearly total. This mode is more accurate because it uses your real habits instead of a national average.
If you can, weigh your bin. Put a kitchen scale under the trash for a week, or weigh a few full food-waste bags, and use the real number. Averages hide a lot of variation, and most people guess wrong about how much they actually throw away. A measured pound beats an assumed one every time.
Once you have a result, switch between the two modes to see how your household compares to the average. If the weighed number is much higher than the household-size estimate, that gap is your opportunity.
The formula, and the 0.74 number
The core calculation is deliberately simple, and the page shows it in full:
landfill CO2e = food waste (kg/year) × 0.74 kg CO2e per kg
miles driven = landfill CO2e ÷ 0.40 kg CO2e per mile
The 0.74 kg CO2e per kg factor comes from the EPA's WARM model and GHG Emission Factors Hub. It represents the methane released when food breaks down in a landfill. This part matters, so it is worth being precise about it.
Food in a landfill does not simply decompose into harmless dirt. It is buried under more trash, sealed off from oxygen. In that oxygen-starved (anaerobic) environment, the bacteria that break it down produce methane rather than plain CO2. Methane traps far more heat than carbon dioxide over the decades right after it is released. That is why a banana peel in a landfill is a climate problem in a way the same peel on a forest floor, decomposing with oxygen, is not.
The miles-driven equivalence exists to make the number legible. Kilograms of CO2e are abstract. Miles in a car are not. We divide the landfill emissions by 0.40 kg CO2e per mile, the EPA's figure for a typical passenger vehicle, so you can compare your trash to something you understand.
Take the worked example the tool uses. A household of four wastes roughly 1,025 lb (465 kg) of food a year. Run that through the formula:
- 465 kg × 0.74 = about 343 kg CO2e of landfill methane.
- 343 kg ÷ 0.40 = about 858 miles of driving.
So one average family's wasted food produces methane equivalent to a road trip from New York City to Atlanta. And as the next section explains, that 343 kg is the smaller half of the story.
The bigger number nobody mentions
The landfill methane is real, but it is not where most of the damage happens. The larger cost was paid long before the food reached your bin.
Every pound of food carries the emissions of growing it. Tractors burned diesel. Fertilizer was manufactured, often using natural gas. Fields were irrigated. The crop was harvested, processed, refrigerated, packaged, and trucked across the country. All of that emits carbon, whether or not anyone eats the result. For an average mix of US food, that embodied or lifecycle cost is around 2.9 kg CO2e per kilogram — roughly four times the 0.74 kg the landfill itself adds.
The USDA notes that more than 85% of food waste's total climate impact happens before the food is ever thrown away, in production and supply rather than in disposal. When you throw out food, you are not just creating landfill methane. You are wasting all the carbon already spent to put that food in front of you.
Run the household-of-four example again with the lifecycle factor. That 465 kg of wasted food carries roughly 1,350 kg CO2e of embodied emissions from production and transport — close to four times the 343 kg the landfill produces. The calculator shows this lifecycle figure alongside the landfill number for exactly this reason.
This reframes everything. The question is not "how do I dispose of food waste more cleanly?" It is "how do I stop producing food waste in the first place?" Because the cleanest disposal method on earth does nothing about the 2.9 kg already spent growing the thing.
Why composting helps — but reducing helps more
Composting is genuinely good, and the calculator gives it full credit. Composted food breaks down with oxygen, so it releases far less methane. Using a compost emission factor of 0.12 kg CO2e per kg against the landfill's 0.74, composting avoids about 84% of the landfill emissions. In the household-of-four example, that is roughly 288 kg CO2e kept out of the air every year. Compost your scraps instead of binning them and you have done real, measurable good.
But notice exactly what composting fixes. It addresses the 0.74. It does nothing about the 2.9. Composting a tomato still wastes every drop of water, fuel, and fertilizer that grew it. You have cleaned up the disposal, not recovered the cost.
That is why the EPA's wasted-food hierarchy puts the steps in this order, and so do we:
- Prevent. Do not buy or cook more than you will eat. This is the only step that avoids both the landfill methane and the production emissions, because the uneaten food never has to exist.
- Rescue. If edible food is surplus, donate it or share it so a person eats it. The carbon spent growing it still does its job.
- Compost. For genuine scraps — peels, cores, coffee grounds, spoiled leftovers — compost rather than landfill.
Compost is the right answer for what is left over. It is the wrong answer if it becomes permission to keep over-buying. Prevention is the only move that touches the big number.
What to do about it
Prevention sounds like discipline, but in practice it is a handful of small kitchen habits. None of them require buying anything.
- Shop to a list. Plan a few meals, write down what they need, and buy that. Most waste starts with optimistic shopping — the salad greens and fresh herbs you meant to use and did not.
- Store food so it lasts. Most produce lasts longer than people assume when it is stored correctly. Keep herbs in water, store onions and potatoes apart, and learn which items belong in the fridge versus the counter.
- Keep an "eat first" shelf. Put the food closest to going off at the front of the fridge, at eye level, on one dedicated shelf. Out of sight is the leading cause of out of date.
- Freeze the surplus. Bread, cooked portions, ripe bananas, and most leftovers freeze well. The freezer is a pause button on food waste.
- Compost what is genuinely scrap. Peels, cores, and grounds were never going to be eaten. Compost them and you avoid most of their landfill methane.
Durable kitchen gear supports the habit without being the point. Reusable produce storage, a basic kitchen scale to weigh your bin, and good airtight containers all help you waste less, and they last for years instead of becoming waste themselves. They are a help, not a substitute for buying less.
Honest limits
This is an estimate, and we would rather tell you where it is soft than pretend it is precise.
- Averages hide huge variation. The 116 kg per-person figure is a national average. Your household may waste far more or far less. Weighing your bin fixes this; the household-size mode does not.
- Not all food is equal. The embodied-carbon factor is an average across the whole food supply. Wasting a pound of beef is dramatically worse than wasting a pound of vegetables — beef can carry many times the emissions of produce. The calculator does not ask what kind of food you waste, so it smooths over a difference that can be very large.
- Landfills vary. Some capture a share of their methane and burn it for energy, which lowers real-world emissions below the 0.74 factor. Others capture little or nothing. The factor is a reasonable average, not a reading of your specific landfill.
- Composting is not free of emissions. It still produces some, which is why the compost factor is 0.12 rather than zero. Backyard composting done badly can emit more than done well.
Treat the output as a credible order-of-magnitude estimate. It is built to show you roughly how big the problem is and where the leverage sits, not to certify a precise carbon figure. We publish the number, not the vibe — and the honest number is "about this much," not "exactly this much."
Frequently asked questions
Is composting enough to fix food waste?
No. Composting avoids about 84% of the landfill methane, which is real and worth doing. But it does nothing about the roughly 2.9 kg CO2e per kg already spent growing and shipping the food — and the USDA notes that more than 85% of food waste's climate impact happens before disposal. Compost what is left over, but reduce what you waste first.
Why measure emissions in "miles driven"?
Because kilograms of CO2e mean little to most people, and miles in a car mean a lot. We divide your landfill emissions by the EPA's typical-vehicle figure of 0.40 kg CO2e per mile so you have a concrete comparison you can feel. It is a translation for scale, not a claim that food waste and driving are the same activity. The point is to make an invisible cost visible enough to act on.
Should I use household size or weigh my bin?
Weigh your bin if you can. Household size uses a national average that may be far from your reality. A week of actually weighing your trash gives you a number based on your habits, which is both more accurate and more useful for spotting where to cut.
Where do these numbers come from?
The per-person waste figure is from the EPA's 2025 report Estimating the Cost of Food Waste to American Consumers. The 0.74 landfill factor is from the EPA's GHG Emission Factors Hub and WARM model. The 0.40 kg per mile car figure is the EPA's typical passenger vehicle estimate. The lifecycle and composting factors are drawn from published US averages. Every factor is shown on the page so you can check our math.