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Carbon Footprint worksheet

Grade 7 · CCSS 7.EE.B.3

Solve each problem and show your work. Round answers to 2 decimal places where needed.

1.
Problem 1.
- People in the household: 2
- Electricity used per month: 950 kWh
- Electricity factor (EPA 2025, US average grid: 0.35): 0.42 kg CO2/kWh
- Natural gas used per month: 30 therms
- Natural gas factor (EPA 2025: 5.306): 4.75 kg CO2/therm
- Heating oil used per year: 0 gal
- Heating oil factor (EPA 2025: 10.21): 7.5 kg CO2/gal
- Propane used per year: 0 gal
- Propane factor (EPA 2025: 5.72): 5.5 kg CO2/gal
- Miles driven per year (all household cars): 12,000 mi
- Average fuel economy: 32 mpg
- Fuel: Diesel
- Diesel factor (EPA 2025: 10.21): 9.5 kg CO2/gal
- Flight miles per year: short trips (under 300 mi): 0 mi
- Short-haul factor (EPA 2025: 0.207): 0.18 kg CO2/passenger-mi
- Flight miles per year: medium trips (300–2,300 mi): 1,300 mi
- Medium-haul factor (EPA 2025: 0.129): 0.16 kg CO2/passenger-mi
- Flight miles per year: long trips (2,300 mi or more): 0 mi
- Long-haul factor (EPA 2025: 0.163): 0.16 kg CO2/passenger-mi
Find: Estimated CO2 per year
Answer
2.
Problem 2.
- People in the household: 3
- Electricity used per month: 750 kWh
- Electricity factor (EPA 2025, US average grid: 0.35): 0.45 kg CO2/kWh
- Natural gas used per month: 44 therms
- Natural gas factor (EPA 2025: 5.306): 5.4 kg CO2/therm
- Heating oil used per year: 0 gal
- Heating oil factor (EPA 2025: 10.21): 10 kg CO2/gal
- Propane used per year: 0 gal
- Propane factor (EPA 2025: 5.72): 5.5 kg CO2/gal
- Miles driven per year (all household cars): 9,000 mi
- Average fuel economy: 22 mpg
- Fuel: Diesel
- Diesel factor (EPA 2025: 10.21): 7 kg CO2/gal
- Flight miles per year: short trips (under 300 mi): 0 mi
- Short-haul factor (EPA 2025: 0.207): 0.22 kg CO2/passenger-mi
- Flight miles per year: medium trips (300–2,300 mi): 1,800 mi
- Medium-haul factor (EPA 2025: 0.129): 0.16 kg CO2/passenger-mi
- Flight miles per year: long trips (2,300 mi or more): 0 mi
- Long-haul factor (EPA 2025: 0.163): 0.09 kg CO2/passenger-mi
Find: Estimated CO2 per year
Answer
3.
Problem 3.
- People in the household: 2
- Electricity used per month: 1,250 kWh
- Electricity factor (EPA 2025, US average grid: 0.35): 0.26 kg CO2/kWh
- Natural gas used per month: 40 therms
- Natural gas factor (EPA 2025: 5.306): 6.8 kg CO2/therm
- Heating oil used per year: 0 gal
- Heating oil factor (EPA 2025: 10.21): 8 kg CO2/gal
- Propane used per year: 0 gal
- Propane factor (EPA 2025: 5.72): 7 kg CO2/gal
- Miles driven per year (all household cars): 9,500 mi
- Average fuel economy: 22 mpg
- Fuel: Gasoline
- Gasoline factor (EPA 2025: 8.78): 10 kg CO2/gal
- Flight miles per year: short trips (under 300 mi): 0 mi
- Short-haul factor (EPA 2025: 0.207): 0.18 kg CO2/passenger-mi
- Flight miles per year: medium trips (300–2,300 mi): 1,800 mi
- Medium-haul factor (EPA 2025: 0.129): 0.11 kg CO2/passenger-mi
- Flight miles per year: long trips (2,300 mi or more): 0 mi
- Long-haul factor (EPA 2025: 0.163): 0.19 kg CO2/passenger-mi
Find: Estimated CO2 per year
Answer
4.
Problem 4.
- People in the household: 2
- Electricity used per month: 700 kWh
- Electricity factor (EPA 2025, US average grid: 0.35): 0.3 kg CO2/kWh
- Natural gas used per month: 44 therms
- Natural gas factor (EPA 2025: 5.306): 4.4 kg CO2/therm
- Heating oil used per year: 0 gal
- Heating oil factor (EPA 2025: 10.21): 11 kg CO2/gal
- Propane used per year: 0 gal
- Propane factor (EPA 2025: 5.72): 7 kg CO2/gal
- Miles driven per year (all household cars): 11,000 mi
- Average fuel economy: 26 mpg
- Fuel: Diesel
- Diesel factor (EPA 2025: 10.21): 11.5 kg CO2/gal
- Flight miles per year: short trips (under 300 mi): 0 mi
- Short-haul factor (EPA 2025: 0.207): 0.16 kg CO2/passenger-mi
- Flight miles per year: medium trips (300–2,300 mi): 1,950 mi
- Medium-haul factor (EPA 2025: 0.129): 0.09 kg CO2/passenger-mi
- Flight miles per year: long trips (2,300 mi or more): 0 mi
- Long-haul factor (EPA 2025: 0.163): 0.2 kg CO2/passenger-mi
Find: Estimated CO2 per year
Answer
5.
Problem 5.
- People in the household: 2
- Electricity used per month: 1,050 kWh
- Electricity factor (EPA 2025, US average grid: 0.35): 0.28 kg CO2/kWh
- Natural gas used per month: 34 therms
- Natural gas factor (EPA 2025: 5.306): 6.6 kg CO2/therm
- Heating oil used per year: 0 gal
- Heating oil factor (EPA 2025: 10.21): 10 kg CO2/gal
- Propane used per year: 0 gal
- Propane factor (EPA 2025: 5.72): 5 kg CO2/gal
- Miles driven per year (all household cars): 13,500 mi
- Average fuel economy: 34 mpg
- Fuel: Diesel
- Diesel factor (EPA 2025: 10.21): 9.25 kg CO2/gal
- Flight miles per year: short trips (under 300 mi): 0 mi
- Short-haul factor (EPA 2025: 0.207): 0.225 kg CO2/passenger-mi
- Flight miles per year: medium trips (300–2,300 mi): 1,600 mi
- Medium-haul factor (EPA 2025: 0.129): 0.1 kg CO2/passenger-mi
- Flight miles per year: long trips (2,300 mi or more): 0 mi
- Long-haul factor (EPA 2025: 0.163): 0.2 kg CO2/passenger-mi
Find: Estimated CO2 per year
Answer
6.
Problem 6.
- People in the household: 2
- Electricity used per month: 1,100 kWh
- Electricity factor (EPA 2025, US average grid: 0.35): 0.36 kg CO2/kWh
- Natural gas used per month: 50 therms
- Natural gas factor (EPA 2025: 5.306): 5 kg CO2/therm
- Heating oil used per year: 0 gal
- Heating oil factor (EPA 2025: 10.21): 12.5 kg CO2/gal
- Propane used per year: 0 gal
- Propane factor (EPA 2025: 5.72): 5.5 kg CO2/gal
- Miles driven per year (all household cars): 10,000 mi
- Average fuel economy: 23 mpg
- Fuel: Diesel
- Diesel factor (EPA 2025: 10.21): 7 kg CO2/gal
- Flight miles per year: short trips (under 300 mi): 0 mi
- Short-haul factor (EPA 2025: 0.207): 0.2 kg CO2/passenger-mi
- Flight miles per year: medium trips (300–2,300 mi): 2,400 mi
- Medium-haul factor (EPA 2025: 0.129): 0.13 kg CO2/passenger-mi
- Flight miles per year: long trips (2,300 mi or more): 0 mi
- Long-haul factor (EPA 2025: 0.163): 0.23 kg CO2/passenger-mi
Find: Estimated CO2 per year
Answer
7.
Problem 7.
- People in the household: 3
- Electricity used per month: 875 kWh
- Electricity factor (EPA 2025, US average grid: 0.35): 0.28 kg CO2/kWh
- Natural gas used per month: 48 therms
- Natural gas factor (EPA 2025: 5.306): 5 kg CO2/therm
- Heating oil used per year: 0 gal
- Heating oil factor (EPA 2025: 10.21): 13 kg CO2/gal
- Propane used per year: 0 gal
- Propane factor (EPA 2025: 5.72): 4 kg CO2/gal
- Miles driven per year (all household cars): 9,500 mi
- Average fuel economy: 18 mpg
- Fuel: Diesel
- Diesel factor (EPA 2025: 10.21): 10.25 kg CO2/gal
- Flight miles per year: short trips (under 300 mi): 0 mi
- Short-haul factor (EPA 2025: 0.207): 0.2 kg CO2/passenger-mi
- Flight miles per year: medium trips (300–2,300 mi): 1,475 mi
- Medium-haul factor (EPA 2025: 0.129): 0.15 kg CO2/passenger-mi
- Flight miles per year: long trips (2,300 mi or more): 0 mi
- Long-haul factor (EPA 2025: 0.163): 0.16 kg CO2/passenger-mi
Find: Estimated CO2 per year
Answer
8.
Problem 8.
- People in the household: 2
- Electricity used per month: 750 kWh
- Electricity factor (EPA 2025, US average grid: 0.35): 0.45 kg CO2/kWh
- Natural gas used per month: 36 therms
- Natural gas factor (EPA 2025: 5.306): 6.5 kg CO2/therm
- Heating oil used per year: 0 gal
- Heating oil factor (EPA 2025: 10.21): 13 kg CO2/gal
- Propane used per year: 0 gal
- Propane factor (EPA 2025: 5.72): 4.5 kg CO2/gal
- Miles driven per year (all household cars): 11,000 mi
- Average fuel economy: 26 mpg
- Fuel: Gasoline
- Gasoline factor (EPA 2025: 8.78): 9.5 kg CO2/gal
- Flight miles per year: short trips (under 300 mi): 0 mi
- Short-haul factor (EPA 2025: 0.207): 0.2 kg CO2/passenger-mi
- Flight miles per year: medium trips (300–2,300 mi): 2,400 mi
- Medium-haul factor (EPA 2025: 0.129): 0.115 kg CO2/passenger-mi
- Flight miles per year: long trips (2,300 mi or more): 0 mi
- Long-haul factor (EPA 2025: 0.163): 0.16 kg CO2/passenger-mi
Find: Estimated CO2 per year
Answer
9.
Problem 9.
- People in the household: 3
- Electricity used per month: 850 kWh
- Electricity factor (EPA 2025, US average grid: 0.35): 0.36 kg CO2/kWh
- Natural gas used per month: 54 therms
- Natural gas factor (EPA 2025: 5.306): 4 kg CO2/therm
- Heating oil used per year: 0 gal
- Heating oil factor (EPA 2025: 10.21): 6.75 kg CO2/gal
- Propane used per year: 0 gal
- Propane factor (EPA 2025: 5.72): 5.1 kg CO2/gal
- Miles driven per year (all household cars): 15,000 mi
- Average fuel economy: 24 mpg
- Fuel: Gasoline
- Gasoline factor (EPA 2025: 8.78): 7.5 kg CO2/gal
- Flight miles per year: short trips (under 300 mi): 0 mi
- Short-haul factor (EPA 2025: 0.207): 0.25 kg CO2/passenger-mi
- Flight miles per year: medium trips (300–2,300 mi): 3,000 mi
- Medium-haul factor (EPA 2025: 0.129): 0.11 kg CO2/passenger-mi
- Flight miles per year: long trips (2,300 mi or more): 0 mi
- Long-haul factor (EPA 2025: 0.163): 0.14 kg CO2/passenger-mi
Find: Estimated CO2 per year
Answer
10.
Problem 10.
- People in the household: 2
- Electricity used per month: 550 kWh
- Electricity factor (EPA 2025, US average grid: 0.35): 0.32 kg CO2/kWh
- Natural gas used per month: 38 therms
- Natural gas factor (EPA 2025: 5.306): 6 kg CO2/therm
- Heating oil used per year: 0 gal
- Heating oil factor (EPA 2025: 10.21): 8 kg CO2/gal
- Propane used per year: 0 gal
- Propane factor (EPA 2025: 5.72): 6.25 kg CO2/gal
- Miles driven per year (all household cars): 15,500 mi
- Average fuel economy: 24 mpg
- Fuel: Diesel
- Diesel factor (EPA 2025: 10.21): 6.75 kg CO2/gal
- Flight miles per year: short trips (under 300 mi): 0 mi
- Short-haul factor (EPA 2025: 0.207): 0.22 kg CO2/passenger-mi
- Flight miles per year: medium trips (300–2,300 mi): 1,450 mi
- Medium-haul factor (EPA 2025: 0.129): 0.13 kg CO2/passenger-mi
- Flight miles per year: long trips (2,300 mi or more): 0 mi
- Long-haul factor (EPA 2025: 0.163): 0.17 kg CO2/passenger-mi
Find: Estimated CO2 per year
Answer

Answer key: Carbon Footprint worksheet

1. Estimated CO2 per year: 10.27 t
1. Electricity: kWh per month × 12 months × factor
  $950 kWh \times 12 \times 0.42$ $= 4,788 kg$
2. Natural gas: therms per month × 12 months × factor
  $30 therms \times 12 \times 4.75$ $= 1,710 kg$
3. Fuel burned = miles ÷ miles per gallon
  $\frac{12,000 mi}{32 mpg}$ $= 375 gal$
4. Driving: gallons × diesel factor
  $375 gal \times 9.5$ $= 3,562.5 kg$
5. Flights: miles in each distance band × its factor
  $0 \times 0.18 + 1,300 \times 0.16 + 0 \times 0.16$ $= 208 kg$
6. Add up every source for the yearly total
  $4,788 + 1,710 + 0 + 3,562.5 + 208$ $= 10,268.5 kg$
7. Divide by 1,000 to turn kilograms into metric tonnes, which are easier to read (1 tonne is 1,000 kg)
  $\frac{10,268.5 kg}{1,000}$ $= 10.2685 t$
2. Estimated CO2 per year: 10.05 t
1. Electricity: kWh per month × 12 months × factor
  $750 kWh \times 12 \times 0.45$ $= 4,050 kg$
2. Natural gas: therms per month × 12 months × factor
  $44 therms \times 12 \times 5.4$ $= 2,851.2 kg$
3. Fuel burned = miles ÷ miles per gallon
  $\frac{9,000 mi}{22 mpg}$ $= 409.0909 gal$
4. Driving: gallons × diesel factor
  $409.0909 gal \times 7$ $= 2,863.6364 kg$
5. Flights: miles in each distance band × its factor
  $0 \times 0.22 + 1,800 \times 0.16 + 0 \times 0.09$ $= 288 kg$
6. Add up every source for the yearly total
  $4,050 + 2,851.2 + 0 + 2,863.6364 + 288$ $= 10,052.8364 kg$
7. Divide by 1,000 to turn kilograms into metric tonnes, which are easier to read (1 tonne is 1,000 kg)
  $\frac{10,052.8364 kg}{1,000}$ $= 10.052836 t$
3. Estimated CO2 per year: 11.68 t
1. Electricity: kWh per month × 12 months × factor
  $1,250 kWh \times 12 \times 0.26$ $= 3,900 kg$
2. Natural gas: therms per month × 12 months × factor
  $40 therms \times 12 \times 6.8$ $= 3,264 kg$
3. Fuel burned = miles ÷ miles per gallon
  $\frac{9,500 mi}{22 mpg}$ $= 431.8182 gal$
4. Driving: gallons × gasoline factor
  $431.8182 gal \times 10$ $= 4,318.1818 kg$
5. Flights: miles in each distance band × its factor
  $0 \times 0.18 + 1,800 \times 0.11 + 0 \times 0.19$ $= 198 kg$
6. Add up every source for the yearly total
  $3,900 + 3,264 + 0 + 4,318.1818 + 198$ $= 11,680.1818 kg$
7. Divide by 1,000 to turn kilograms into metric tonnes, which are easier to read (1 tonne is 1,000 kg)
  $\frac{11,680.1818 kg}{1,000}$ $= 11.680182 t$
4. Estimated CO2 per year: 9.88 t
1. Electricity: kWh per month × 12 months × factor
  $700 kWh \times 12 \times 0.3$ $= 2,520 kg$
2. Natural gas: therms per month × 12 months × factor
  $44 therms \times 12 \times 4.4$ $= 2,323.2 kg$
3. Fuel burned = miles ÷ miles per gallon
  $\frac{11,000 mi}{26 mpg}$ $= 423.0769 gal$
4. Driving: gallons × diesel factor
  $423.0769 gal \times 11.5$ $= 4,865.3846 kg$
5. Flights: miles in each distance band × its factor
  $0 \times 0.16 + 1,950 \times 0.09 + 0 \times 0.2$ $= 175.5 kg$
6. Add up every source for the yearly total
  $2,520 + 2,323.2 + 0 + 4,865.3846 + 175.5$ $= 9,884.0846 kg$
7. Divide by 1,000 to turn kilograms into metric tonnes, which are easier to read (1 tonne is 1,000 kg)
  $\frac{9,884.0846 kg}{1,000}$ $= 9.884085 t$
5. Estimated CO2 per year: 10.05 t
1. Electricity: kWh per month × 12 months × factor
  $1,050 kWh \times 12 \times 0.28$ $= 3,528 kg$
2. Natural gas: therms per month × 12 months × factor
  $34 therms \times 12 \times 6.6$ $= 2,692.8 kg$
3. Fuel burned = miles ÷ miles per gallon
  $\frac{13,500 mi}{34 mpg}$ $= 397.0588 gal$
4. Driving: gallons × diesel factor
  $397.0588 gal \times 9.25$ $= 3,672.7941 kg$
5. Flights: miles in each distance band × its factor
  $0 \times 0.225 + 1,600 \times 0.1 + 0 \times 0.2$ $= 160 kg$
6. Add up every source for the yearly total
  $3,528 + 2,692.8 + 0 + 3,672.7941 + 160$ $= 10,053.5941 kg$
7. Divide by 1,000 to turn kilograms into metric tonnes, which are easier to read (1 tonne is 1,000 kg)
  $\frac{10,053.5941 kg}{1,000}$ $= 10.053594 t$
6. Estimated CO2 per year: 11.11 t
1. Electricity: kWh per month × 12 months × factor
  $1,100 kWh \times 12 \times 0.36$ $= 4,752 kg$
2. Natural gas: therms per month × 12 months × factor
  $50 therms \times 12 \times 5$ $= 3,000 kg$
3. Fuel burned = miles ÷ miles per gallon
  $\frac{10,000 mi}{23 mpg}$ $= 434.7826 gal$
4. Driving: gallons × diesel factor
  $434.7826 gal \times 7$ $= 3,043.4783 kg$
5. Flights: miles in each distance band × its factor
  $0 \times 0.2 + 2,400 \times 0.13 + 0 \times 0.23$ $= 312 kg$
6. Add up every source for the yearly total
  $4,752 + 3,000 + 0 + 3,043.4783 + 312$ $= 11,107.4783 kg$
7. Divide by 1,000 to turn kilograms into metric tonnes, which are easier to read (1 tonne is 1,000 kg)
  $\frac{11,107.4783 kg}{1,000}$ $= 11.107478 t$
7. Estimated CO2 per year: 11.45 t
1. Electricity: kWh per month × 12 months × factor
  $875 kWh \times 12 \times 0.28$ $= 2,940 kg$
2. Natural gas: therms per month × 12 months × factor
  $48 therms \times 12 \times 5$ $= 2,880 kg$
3. Fuel burned = miles ÷ miles per gallon
  $\frac{9,500 mi}{18 mpg}$ $= 527.7778 gal$
4. Driving: gallons × diesel factor
  $527.7778 gal \times 10.25$ $= 5,409.7222 kg$
5. Flights: miles in each distance band × its factor
  $0 \times 0.2 + 1,475 \times 0.15 + 0 \times 0.16$ $= 221.25 kg$
6. Add up every source for the yearly total
  $2,940 + 2,880 + 0 + 5,409.7222 + 221.25$ $= 11,450.9722 kg$
7. Divide by 1,000 to turn kilograms into metric tonnes, which are easier to read (1 tonne is 1,000 kg)
  $\frac{11,450.9722 kg}{1,000}$ $= 11.450972 t$
8. Estimated CO2 per year: 11.15 t
1. Electricity: kWh per month × 12 months × factor
  $750 kWh \times 12 \times 0.45$ $= 4,050 kg$
2. Natural gas: therms per month × 12 months × factor
  $36 therms \times 12 \times 6.5$ $= 2,808 kg$
3. Fuel burned = miles ÷ miles per gallon
  $\frac{11,000 mi}{26 mpg}$ $= 423.0769 gal$
4. Driving: gallons × gasoline factor
  $423.0769 gal \times 9.5$ $= 4,019.2308 kg$
5. Flights: miles in each distance band × its factor
  $0 \times 0.2 + 2,400 \times 0.115 + 0 \times 0.16$ $= 276 kg$
6. Add up every source for the yearly total
  $4,050 + 2,808 + 0 + 4,019.2308 + 276$ $= 11,153.2308 kg$
7. Divide by 1,000 to turn kilograms into metric tonnes, which are easier to read (1 tonne is 1,000 kg)
  $\frac{11,153.2308 kg}{1,000}$ $= 11.153231 t$
9. Estimated CO2 per year: 11.28 t
1. Electricity: kWh per month × 12 months × factor
  $850 kWh \times 12 \times 0.36$ $= 3,672 kg$
2. Natural gas: therms per month × 12 months × factor
  $54 therms \times 12 \times 4$ $= 2,592 kg$
3. Fuel burned = miles ÷ miles per gallon
  $\frac{15,000 mi}{24 mpg}$ $= 625 gal$
4. Driving: gallons × gasoline factor
  $625 gal \times 7.5$ $= 4,687.5 kg$
5. Flights: miles in each distance band × its factor
  $0 \times 0.25 + 3,000 \times 0.11 + 0 \times 0.14$ $= 330 kg$
6. Add up every source for the yearly total
  $3,672 + 2,592 + 0 + 4,687.5 + 330$ $= 11,281.5 kg$
7. Divide by 1,000 to turn kilograms into metric tonnes, which are easier to read (1 tonne is 1,000 kg)
  $\frac{11,281.5 kg}{1,000}$ $= 11.2815 t$
10. Estimated CO2 per year: 9.4 t
1. Electricity: kWh per month × 12 months × factor
  $550 kWh \times 12 \times 0.32$ $= 2,112 kg$
2. Natural gas: therms per month × 12 months × factor
  $38 therms \times 12 \times 6$ $= 2,736 kg$
3. Fuel burned = miles ÷ miles per gallon
  $\frac{15,500 mi}{24 mpg}$ $= 645.8333 gal$
4. Driving: gallons × diesel factor
  $645.8333 gal \times 6.75$ $= 4,359.375 kg$
5. Flights: miles in each distance band × its factor
  $0 \times 0.22 + 1,450 \times 0.13 + 0 \times 0.17$ $= 188.5 kg$
6. Add up every source for the yearly total
  $2,112 + 2,736 + 0 + 4,359.375 + 188.5$ $= 9,395.875 kg$
7. Divide by 1,000 to turn kilograms into metric tonnes, which are easier to read (1 tonne is 1,000 kg)
  $\frac{9,395.875 kg}{1,000}$ $= 9.395875 t$