Rex says
Everyday utility math — the kind you'd otherwise pull up four browser tabs for. I keep it to one clean answer.
Try a scenario
Click to load — tweak from there.Inputs
Result
Total Scope 1+2 emissions
428.3
Scope 1 (direct)
235.3
Scope 2 (electricity)
193.0
Average per month
35.69
Share from electricity
45%
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How to use this
- 1Enter natural gas used (therms/yr).
- 2Enter diesel/fuel oil used (gal/yr).
- 3Enter propane used (gal/yr).
- 4Enter purchased electricity (kWh/yr).
- 5Enter grid emission factor (kg CO2e/kWh).
- 6Read your total scope 1+2 emissions on the right — it updates as you type.
- 7Hit Share to keep the scenario or send it to someone.
About this calculator
Scope 1 covers fuel you burn on-site or in owned vehicles — natural gas, diesel, propane. Scope 2 covers purchased electricity, using the grid's emission factor for your region. This calculator takes your annual gas therms, fuel gallons, and electricity kWh, applies EPA-standard emission factors, and rolls them into a total metric-ton CO2e figure you can report or benchmark. It is the same math behind most corporate GHG inventories built to the GHG Protocol, minus the audit trail. Grid factors vary a lot by region — a kWh in the Pacific Northwest can be 5-10x cleaner than one in a coal-heavy grid, so the eGRID subregion factor input matters more than people expect. Use this for a first-pass inventory, board reporting, or CDP prep, then refine with your actual utility invoice emission factors when you need audit-grade numbers.
Worked example
Using the values the calculator loads with:
Inputs
- Natural gas used: 40000 therms/yr
- Diesel/fuel oil used: 2000 gal/yr
- Propane used: 500 gal/yr
- Purchased electricity: 500000 kWh/yr
- Grid emission factor: 0.386 kg CO2e/kWh
Results
- Total Scope 1+2 emissions: 428.3
- Scope 1 (direct): 235.3
- Scope 2 (electricity): 193
- Average per month: 35.69
- Share from electricity: 45%
What each field means
Inputs
- Natural gas used (therms/yr)
- The natural gas used used in the calculation, measured in therms/yr. Starts at 40000 therms/yr so you have a working example on load.
- Diesel/fuel oil used (gal/yr)
- The diesel/fuel oil used used in the calculation, measured in gal/yr. Starts at 2000 gal/yr so you have a working example on load.
- Propane used (gal/yr)
- The propane used used in the calculation, measured in gal/yr. Starts at 500 gal/yr so you have a working example on load.
- Purchased electricity (kWh/yr)
- The purchased electricity used in the calculation, measured in kWh/yr. Starts at 500000 kWh/yr so you have a working example on load.
- Grid emission factor (kg CO2e/kWh)
- The grid emission factor used in the calculation, measured in kg CO2e/kWh. Starts at 0.386 kg CO2e/kWh so you have a working example on load.
Results
- Total Scope 1+2 emissions
- Returned as a whole number and shown as the headline result. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Scope 1 (direct)
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Scope 2 (electricity)
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Average per month
- Returned as a whole number. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
- Share from electricity
- Returned as a percentage. It recalculates instantly whenever you change an input, so you can compare scenarios without reloading.
FAQ
Where do I get my grid emission factor?
EPA's eGRID database publishes subregion factors updated roughly every two years; utilities sometimes print a factor on the bill too. The US average is around 0.386 kg CO2e/kWh but ranges from under 0.1 in hydro-heavy regions like the Pacific Northwest to over 0.7 in coal-dependent grids, so pull the number for your specific service territory.
Do I need Scope 3 too?
For CDP, SBTi, or most investor-grade disclosures, yes — Scope 3 (supply chain, business travel, commuting, purchased goods) is usually the largest bucket. This calculator only covers Scope 1 and 2, which is the right starting point for a first inventory or SEC climate disclosure baseline.
How accurate are the default emission factors?
The natural gas factor (0.0053 tCO2e/therm) and diesel/propane factors come from EPA's Emission Factors Hub and are accurate to within a few percent for combustion-only accounting. They exclude upstream methane leakage, which matters for lifecycle-scope claims but not for a standard operational inventory.
Should I use market-based or location-based Scope 2?
This tool computes location-based Scope 2 using the grid average. If you have signed a renewable energy contract or REC purchase, market-based accounting can show a lower number — GHG Protocol requires you to report both when you have contractual instruments.
Accuracy and limitations
- Estimates assume standard, average conditions — local rules, pricing, and materials vary.
- Results are rounded for readability; add a buffer before ordering, booking, or committing.
- Double-check anything with a real cost attached against a local quote.
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Emissions per dollar of spend by supplier category, spend-based method.
Cite this calculator
Writing about this topic? Grab a citation — every link helps keep these tools free.
RevenueLab. (2026). Scope 1 & 2 Emissions Calculator. Retrieved from https://www.revenuelab.fyi/toolbox/scope1-2-emissions
<p>Source: <a href="https://www.revenuelab.fyi/toolbox/scope1-2-emissions" target="_blank" rel="noopener">Scope 1 & 2 Emissions Calculator — RevenueLab</a> (2026).</p>
Source: [Scope 1 & 2 Emissions Calculator — RevenueLab](https://www.revenuelab.fyi/toolbox/scope1-2-emissions) (2026).