7 Best Carbon Footprint Calculators

If you’re trying to calculate your carbon footprint, this guide will show you which calculator is right for you.

I tested seven of the best carbon footprint calculators and rated them based on their comprehensiveness across the four main categories of household consumption:

  • Transportation
  • Housing
  • Food
  • Goods, services, and leisure1

Doing so quickly revealed which of the top carbon calculators offer more complete carbon footprint estimates…and which are limited.

Best Carbon Footprint Calculators

  1. CoolClimate Calculator
  2. WWF Footprint Calculator
  3. CarbonFootprint.com Carbon Calculator
  4. Conservation International Carbon Footprint Calculator
  5. UN Carbon Footprint Calculator
  6. TerraPass Carbon Footprint Calculator
  7. EPA Carbon Footprint Calculator

1. CoolClimate Calculator: Best for US Residents

CoolClimate Calculator

The CoolClimate Calculator is the most comprehensive carbon calculator I tested designed for US residents. It includes in its calculations the four main categories of household consumption, resulting in an estimate of your carbon footprint that takes into account all the major sources of your personal emissions.

The calculator allows you to plug in granular data for each category. For transportation, it asks for your annual mileage from a variety of methods. For housing, it asks for your energy usage from all the major home energy sources.

For food, you input your average daily servings of several different types of food. Most calculators simply ask how much meat you eat.

Related: Best Food Carbon Footprint Calculators

Lastly, its goods, services, and leisure section is one of the most comprehensive I’ve seen.

For most categories it has “Simple” and “Advanced” tabs that you can toggle between. It defaults to Simple which is good for quicker calculations, but I recommend using the Advanced options to fine-tune your estimates.

Unlike most carbon calculators, the CoolClimate Calculator includes estimated amortized emissions from the manufacturing of your car and construction of your home.

It’s a helpful reminder that a substantial percentage of a car’s or home’s carbon footprint comes from its production. But, if you didn’t buy a new car or build a new home in the year you’re calculating, you can subtract these two amounts from your total to get a more accurate estimate of how much you emitted that year.

The CoolClimate Calculator is designed for US residents, which is to say its emissions estimates are based mainly on US data. Non-US residents should look at the other options on this list. Or, search for a calculator that is specific to your country.


  • Main categories of household consumption included: 4/4
  • Target locale: United States

2. WWF Footprint Calculator: Best for UK Residents

WWF Footprint Calculator

The WWF calculator is the most user-friendly I tested. Instead of asking you to provide exact numbers for your energy usage, annual mileage, and the like — which most of us don’t have on hand — it asks you simple multiple choice questions.

It’s also one of the most comprehensive. It includes the four main categories of household consumption and asks a number of questions about each.

The WWF calculator is intended for UK residents, with data coming from the Office for National Statistics. On the results page it even compares your estimated footprint to the UK government’s 2020 target.

It asks where you live, but if it’s not in the UK it doesn’t even let you select your country of residence. It simply remains as “Other.”


  • Main categories of household consumption included: 4/4
  • Target locale: United Kingdom

3. CarbonFootprint.com Carbon Calculator: Best for Residents of Calculator-less Countries

CarbonFootprint.com Carbon Calculator

Its interface is clunky, but this carbon calculator is easily one of the most comprehensive. There are sections covering each of the four main categories of household consumption asking you to enter specific numbers for everything from your public transportation usage to groceries spending.

The calculator allows you to enter your country of residence. Doing so compares your footprint to your country’s average and also adjusts your electricity emissions based on the carbon intensity of your country’s grid electricity.

Because of its comprehensiveness and the minor adjustments it makes based on your country of residence, this is the calculator I recommend for people who live outside of the US and UK who can’t find a calculator specific to their own country.

However, the calculator draws most of its data from the UK government’s emission conversion factors. You should therefore take the results with a large grain of salt if you don’t live in the UK. It can offer highly inaccurate estimates for residents of other countries.

For instance, the CarbonFootprint.com Calculator estimates riding 1,000 miles in a long-distance train to have a footprint of 0.011 US tons (0.01 metric tons). The CoolClimate Calculator estimates the same distance to have a footprint of 0.23 US tons (0.209 metric tons) — nearly twenty-one times greater. The discrepancy is due to the carbon intensity of public transportation across countries.

Most carbon calculators suffer from this shortcoming. At some point they decide which country’s emissions data to use for their calculations.

Thus, the best carbon footprint calculator for you might be one that is specific to your country. Only if one doesn’t exist — or if it doesn’t include the four main categories of household consumption — should you consider using this one.


  • Main categories of household consumption included: 4/4
  • Target locale: United Kingdom

4. Conservation International Carbon Footprint Calculator

Conservation International Carbon Footprint Calculator

Technically this calculator includes in its estimates the four main categories of household consumption. However, two of the four are limited in scope.

It only asks one question about food. And instead of asking any questions about goods, services, and leisure, it automatically adds four tons of CO2 to your total to cover this category.

That’s better than not including it at all like the remaining calculators on this list. But of course it won’t produce as fine-tuned an estimate of your carbon footprint as the ones above that account for your lifestyle and spending habits.

The Conservation International calculator is designed for US residents. It mostly pulls its numbers from EPA data.


  • Main categories of household consumption included: 4/4
  • Target locale: United States

5. UN Carbon Footprint Calculator

UN Carbon Footprint Calculator

The UN carbon calculator mainly asks about your household energy usage and transportation habits. It has very limited questioning about food and goods, services, and leisure. It doesn’t include the latter category in its estimates.

Like some other calculators, this one compares your footprint to the per-capita average of your country and the world. If, like me, you live in the US or another country with a high per-capita average, it’s a helpful, if sobering, reminder of your personal climate impact.

This calculator lets you choose your country of residence and then estimates your household emissions based on the latest country-specific data. It’s a welcome feature when a lot of the most popular carbon calculators are US- or UK-specific, and a good alternative for residents of other countries to the CarbonFootprint.com calculator.


  • Main categories of household consumption included: 3/4
  • Target locale: Variable

6. TerraPass Carbon Footprint Calculator

TerraPass Carbon Footprint Calculator

Only transportation and housing are included in this calculator’s estimates. Accordingly, its estimates will be low relative to other calculators that do include the four main categories of household consumption.

Unless you know going in that food and goods, services, and leisure should also be included for the most comprehensive estimate of your carbon footprint, calculators like this one could leave you to believe your footprint is far lower than it actually is.


  • Main categories of household consumption included: 2/4
  • Target locale: United States

7. EPA Carbon Footprint Calculator

EPA Carbon Footprint Calculator

The EPA’s carbon calculator is embarrassingly incomplete. Its estimates leave out some of the main sources of personal emissions, such as flights, food, goods, services, and leisure.

It’s so incomplete that it’s easier to say what it does include: home energy and car usage. It also asks one question about waste.

As a result, its estimates are greatly underestimated relative to carbon calculators that include all four main categories of household consumption.

For instance, according to the EPA calculator, my 2019 carbon footprint was an estimated 7.19 US tons (6.53 metric tons). According to the CoolClimate Calculator it was 15.8 US tons (14.3 metric tons) — more than double.

I worry that the well-intentioned but uninformed will estimate their footprint with this calculator (or the TerraPass calculator) and conclude it’s far smaller than it actually is. Avoid this one. Opt instead for a more complete estimate.


  • Main categories of household consumption included: 2/4
  • Target locale: United States

What to Do Once You Know Your Carbon Footprint

Reduce it, of course! 🙂

There are many lifestyle changes that will reduce your carbon footprint, but here are the most impactful:

  • Drive less
  • Fly less
  • Switch to renewable energy
  • Eat fewer animal products

How I Reduced My Carbon Footprint

My estimated 2019 carbon footprint was 16.3 US tons (14.8 metric tons), based on the average of the CoolClimate and Conservation International calculators (the two calculators I tested that are US-specific and include all four main categories of household consumption).

My 2020 goal was to reduce my carbon footprint to 10 US tons of CO2. I succeeded and then some, reducing it to just 8 tons. Lockdown ‘helped’ in this regard — I stayed home a lot — but there were other changes I made that had a huge impact:

  • Move closer to downtown. Calculating and tracking my carbon footprint has made me realize that reducing it by any significant amount requires lifestyle change. I’m fortunate enough to be able to make some of these changes. Moving closer to where you work and play can significantly reduce your transportation emissions.
  • Bike more and drive less. Once moving downtown, I was within biking distance of friends and other venues I frequent.
  • Switch 100% of my electricity to a clean energy program. A lot of electric utilities offer this option — call yours or check its website for details.
  • Eat a mostly vegetarian diet. I already do this at home, but tend to eat meat when I go out to eat or when on vacation. In 2020 I was stricter about avoiding animal products.

Should You Buy Carbon Offsets?

A carbon footprint calculator's call to action for you to buy carbon offsets to offset your footprint
Many carbon calculators, such as the Conservation International Carbon Footprint Calculator, encourage you to buy carbon offsets after you’ve calculated your footprint. But should you?

Most of the calculators I tested direct you to a place where you can buy carbon offsets to offset your carbon footprint after you calculate it.

In theory, it sounds like a great idea. Simply spend some money and — voilà! — a chunk of your emissions has been offset by some renewable energy or tree planting project in a developing country.

In practice, the effectiveness of carbon offsets (aka carbon credits) is highly questionable. A 2016 report found that 85% of the projects analyzed had a “low likelihood” of creating real impacts.

Do your own research before deciding whether or not to purchase any. Unfortunately, many carbon offset projects likely aren’t as effective as a cursory glance would lead you to believe.

If you want to reduce your climate impact, it’s best to start by lobbying your government to pass climate legislation and reducing your carbon footprint through lifestyle change. Don’t let carbon offsets be an excuse to continue on in a business-as-usual manner.

How I Tested

Here’s what I did to test these calculators:

  • Compiled a list of the most popular carbon footprint calculators based on their Ahrefs Organic Traffic at the time of publishing2
  • Calculated my 2019 carbon footprint using each calculator
  • Rated the comprehensiveness of each calculator by tracking how many of the four main categories of household consumption it includes as well as the number of questions it asks for each category
  • Examined data sources to determine the target country or countries of each calculator

Using this data I was then able to rank the calculators from most to least comprehensive.

The Bottom Line

The best carbon calculator for you is one that:

  • Is designed for your country of residence
  • Includes all four main categories of household consumption (transportation, housing, food, and goods, services, and leisure)

Avoid calculators that don’t meet these criteria. Their estimates can differ greatly from those that do.

After testing and ranking seven of the best carbon footprint calculators, I think the CoolClimate Calculator is the best for US residents and the WWF Footprint Calculator is best for UK residents.

If there isn’t a carbon calculator designed specifically for the country you live in, I recommend using the CarbonFootprint.com Carbon Calculator. It’s comprehensive and offers some localization. You’ll have to take its results with a grain of salt, however.

Knowing how big your carbon footprint is, and which parts of your lifestyle contribute most, is the critical first step to shrinking it. Congrats!

Now you’re ready to learn how to reduce your carbon footprint so you can mitigate the effects your lifestyle has on climate change.

More importantly, with a keen awareness of what contributes to your own footprint, you’re better informed to support and work towards policies, technologies, and systemic changes that make it easier for all of us to reduce ours collectively.


  1. Lifestyle carbon footprint studies such as this one sometimes separate goods, services, and leisure (or some subset of these three) into their own categories for a total of five or six major domains of household consumption. For this guide I’ve grouped them together to match the categorization of the most comprehensive carbon footprint calculators.
  2. I excluded business carbon footprint calculators and ecological footprint calculators. I also excluded the Nature Conservancy’s Carbon Footprint Calculator because it appears to be a licensed version of the CoolClimate Calculator.
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Alex Beale
Alex Beale
Hi, I'm Alex. I started Footprint Hero to help people reduce their environmental impact. My current obsession is DIY solar power projects, which I've been building since 2020.

24 thoughts on “7 Best Carbon Footprint Calculators”

  1. All these calculators only include usage. How does my working for an environmental charity impact my footprint? What about growing my own veg? What about tree planting schemes. These calculators are greatibg for totting up usage, but not so great for working out contributions. I would love to know if there is a calculator out there that has a more rounded input.

    1. There’s nothing that comprehensive that I know of unfortunately. The closest thing I can think of is an app called LiveGreen.

  2. can you give some idea about the ranges of costs those calculator may incur. Or all of those can be used for free. Thanks.

  3. thanks for the analysis! unfortunately none of these work for because they all make too many assumptions that are incorrect for me. Do you have any recommendations of other carbon calculators that do not make a bunch of assumptions? I am that guy who can tell you off the cuff how many kWh and CCF he uses. I’m not afraid of entering real data.

    1. You’re welcome! The CoolClimate calculator lets you put in kWh per month or year. And its water usage field is a little wonky but you can use their household averages and the percentage slider to approximate your water consumption.

    1. You’re welcome, Nick! Your best bet would be a carbon footprint phone app. My guess is some of those can be used offline. Don’t have any recs but I’m sure there are plenty out there.

  4. Have you come across carbonindependent.org ? This works when you are off line. I’d be interested in your comments Alex.

  5. Have you seen one that lets you put in negative values? Since we got solar, we’re sending more power to the grid than we’re using. But CoolClimate and EPA, at least, won’t let you put in negative values. Also, do you know of one that does actual food miles? CoolClimate assumes you just go to generic grocery stores and buy generic food. A lot of us who care about this problem work very hard to buy locally sourced organic. For my family, we run an organic small farm, so it’s particularly problematic to make assumptions in cases like that.

    Terrific to have a comparison for these tools though. I had the same thoughts about the EPA one – not even counting flights? I may know the people who run that one, actually. I’ll see if I can pass along your comments.

    1. Thank you! I haven’t seen one that lets you put in negative values unfortunately. You’ll have to do some manual calculations — use the CoolClimate calc to find out the carbon intensity of the grid where you live (the lbs of CO2 emitted for every kWh of electricity). Multiply that number by the kWh you send back to the grid and subtract that total from your carbon footprint.

      As for food miles, you’ll have to use a “foodprint” calculator. Here are my recs for those. (And here’s a good piece from Our World in Data that compares how food choice vs food miles affect the carbon footprint of what you eat. It’s helped me for keeping things in perspective!)

      If you could get in contact with the people behind the EPA calculator, that’d be amazing! Making that one more comprehensive would make such a big impact.

  6. Thanks Alex. I shall be using it a public event tomorrow in a location where there is no internet, so it’s useful if only for that reason – but it does look quite good to me, and it’s easy to use.

  7. Have you tried the Earth Hero app carbon calculator? The detail level is similar to CoolClimate, however my CF comes out was 4.5 tons vs CoolClimate’s 9 tons. It looks like CC includes “embodied carbon”, which is carbon to build a house or manufacture a vehicle vs Hero’s “operating carbon”.

    1. Not yet, but I just looked it up and it looks good! I’ll make a note to try it out next time I update this article. That’s encouraging to hear it’s quite detailed.

  8. Hi Alex,
    Thanks for the review, love it.
    I’m curious to know when you tested all the calculators, what were the figures?
    I’m interested to know the discrepancy over the calculators reviewed.
    Thank you


    1. The top 5 calculators all gave me roughly the same results (within a couple tons CO2e of each other). The bottom 2 (TerraPass and EPA) estimated my footprint to be about half as much as the other calculators did because they aren’t as comprehensive.

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