Cost Per Therm Calculator
Use this tool to quickly calculate the cost per therm of natural gas based on your utility bill. Knowing your cost per therm helps you understand your energy expenses and compare rates.
Enter the total cost of your natural gas usage and the total number of therms consumed as shown on your bill.
Enter Your Natural Gas Bill Details
Understanding Cost Per Therm
What is a Therm?
A therm is a unit of heat energy, commonly used for billing natural gas in the United States. One therm is equal to 100,000 British Thermal Units (BTUs). Utility companies measure your gas usage (often in cubic feet or CCFs) and then convert it to therms based on the energy content of the gas delivered.
Why Calculate Cost Per Therm?
Your natural gas bill often includes various charges beyond just the cost of the gas itself (like delivery fees, taxes, service charges). Calculating the "true" cost per therm by dividing your total bill amount by the total therms used gives you a clearer picture of how much you are *actually* paying per unit of energy delivered to your home or business. This is useful for:
- Budgeting and understanding energy costs.
- Comparing rates between different suppliers (if applicable).
- Evaluating the efficiency of appliances or energy-saving measures.
Formula
The calculation is straightforward:
Cost Per Therm = Total Cost / Total Therms Used
Ensure the "Total Cost" includes all charges from your bill that you want to factor into the calculation.
Cost Per Therm Examples
Here are some examples of calculating cost per therm based on different hypothetical bills:
Example 1: Typical Winter Bill
Scenario: Your winter gas bill is $120.50 for 100 therms.
Calculation: $120.50 / 100 therms
Result: $1.205 per therm
Conclusion: Each therm cost approximately $1.21.
Example 2: Lower Usage Month
Scenario: Your bill is $45.00 for 30 therms during a milder month.
Calculation: $45.00 / 30 therms
Result: $1.50 per therm
Conclusion: The cost per therm is higher than Example 1, possibly due to fixed monthly charges being spread over fewer therms.
Example 3: High Bill, High Usage
Scenario: A very cold month results in a $250.75 bill for 220 therms.
Calculation: $250.75 / 220 therms
Result: $1.1397... per therm
Conclusion: The cost per therm is roughly $1.14.
Example 4: Bill with Minimal Usage
Scenario: You used only 5 therms, and the bill is $25.00 (mostly fees).
Calculation: $25.00 / 5 therms
Result: $5.00 per therm
Conclusion: When usage is very low, fixed charges make the cost per therm appear very high.
Example 5: Commercial Bill
Scenario: A business bill is $1500.00 for 1250 therms.
Calculation: $1500.00 / 1250 therms
Result: $1.20 per therm
Conclusion: The commercial cost per therm is $1.20.
Example 6: Estimating Based on Rate (Simplified)
Scenario: Your supplier rate is listed as $0.80/therm, and delivery adds $0.30/therm plus $10 in fees for 50 therms.
Calculation: Total Cost = (50 * $0.80) + (50 * $0.30) + $10 = $40 + $15 + $10 = $65.00. Cost Per Therm = $65.00 / 50 therms
Result: $1.30 per therm
Conclusion: The actual cost per therm ($1.30) is higher than the listed gas rate ($0.80) due to delivery and fees.
Example 7: Tracking Energy Saving Impact
Scenario: Last year's bill was $100 for 80 therms ($1.25/therm). After insulation, this year's comparable bill is $90 for 70 therms.
Calculation: $90.00 / 70 therms
Result: $1.2857... per therm
Conclusion: While usage dropped (good!), the cost per therm slightly increased, potentially due to rate changes or fixed fees on lower usage. Focus on the total cost and therms saved.
Example 8: Comparing Two Bills
Scenario: Bill A: $80 for 65 therms. Bill B: $110 for 90 therms.
Calculation (Bill A): $80.00 / 65 therms ≈ $1.23 per therm
Calculation (Bill B): $110.00 / 90 therms ≈ $1.22 per therm
Conclusion: The cost per therm was slightly lower on the larger Bill B in this instance.
Example 9: Monthly Average
Scenario: Over a year, you paid $1500 total for 1200 therms.
Calculation: $1500.00 / 1200 therms
Result: $1.25 per therm
Conclusion: Your average cost per therm over the year was $1.25.
Example 10: Very Large Bill
Scenario: A factory's bill is $15,000 for 10,000 therms.
Calculation: $15000.00 / 10000 therms
Result: $1.50 per therm
Conclusion: The factory's cost per therm is $1.50.
Frequently Asked Questions about Cost Per Therm
1. What is Cost Per Therm?
Cost per therm is the total amount paid on your natural gas bill divided by the total number of therms used during that billing period. It represents the actual cost for each unit of natural gas energy.
2. Why is my calculated Cost Per Therm different from the rate listed on my bill?
Your bill's listed rate might only be for the cost of the gas commodity itself. Your total bill includes other charges like delivery fees, service fees, taxes, and surcharges, which increase the overall cost per therm you actually pay.
3. Should I include taxes and fees in the Total Cost?
Yes, to calculate your true, all-in cost per therm, you should use the total amount due for the billing period as your "Total Cost" input.
4. Where can I find the Total Cost and Total Therms on my bill?
Look for the "Total Amount Due" or similar wording for the Total Cost. Total Therms Used is usually listed under the usage details, often near where it shows the reading from your meter or the conversion from cubic feet (CCF) to therms.
5. Can I use this for other types of energy?
This specific calculator is for natural gas measured in therms. For electricity, you would calculate cost per kilowatt-hour (kWh) using Total Cost / Total kWh.
6. What if my bill shows CCF instead of Therms?
Most bills that use CCF (hundred cubic feet) will also show the conversion factor (e.g., 1 CCF = 1.024 therms) or the total therms used. Use the total therms figure if available. If only CCF is shown, you would need a different calculator that includes the conversion.
7. Can the Cost Per Therm change each month?
Yes. The price of the natural gas commodity can change, and your total bill might have fixed charges that get spread over varying amounts of therms, causing the average cost per therm to fluctuate.
8. How can I lower my Cost Per Therm?
Focusing on reducing your "Total Therms Used" through conservation and improved efficiency (better insulation, efficient furnace, etc.) is the most direct way to lower your overall bill. Sometimes, switching suppliers can also affect the commodity rate part of the cost.
9. What happens if I enter 0 therms?
If you enter 0 therms, the calculator will show an error because division by zero is not possible. Even with minimal usage, you usually use a small fraction of a therm.
10. Is this calculator suitable for all utility bills?
It's suitable for bills that clearly state the total cost and the total therms used. Ensure you are using the correct numbers from your specific bill.
