Natural Gas Cost Calculator

Frequently Asked Questions

How is natural gas billed?

Usually per therm or per ccf (≈1.037 therms), plus a fixed monthly service charge. 1 therm = 100,000 BTU = ~29.3 kWh.

How do I find an appliance's gas cost?

Appliance BTU/hr × hours ÷ 100,000 = therms used; × your $/therm gives the cost. The calculator also converts therms, ccf, BTU, and m³.

Is gas cheaper than electricity for heat?

Per delivered BTU it usually is, but efficiency matters: a 95% gas furnace vs a heat pump (COP 2–4) can flip the comparison depending on local rates.

Why did my bill rise without using more?

Gas commodity prices and the per-therm rate fluctuate seasonally; the fixed service charge and delivery fees also change independently of usage.

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Estimates for informational purposes only.

Important Disclaimer: Estimates for informational purposes only.

This calculator provides estimates for informational purposes only. Results are based on assumptions and may not reflect actual outcomes. Consult qualified professionals in relevant fields before making important decisions based on these results.

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How This Calculator Works

Natural gas is billed by energy content, not raw volume. The anchor unit is the therm, defined as exactly 100,000 BTU. Utilities meter volume in ccf (hundred cubic feet) and convert using a heating value, typically ≈ 1.037 therm per ccf. Your bill is then: Cost = (therms used × price per therm) + fixed monthly service charge. For appliance estimates we work the other way: an appliance rated in BTU/hr, run for a number of hours over a number of days, consumes (BTU/hr × hours × days) ÷ 100,000 therms. Metric meters report cubic metres (1 m³ ≈ 36,303 BTU).

Worked Example

A furnace rated 60,000 BTU/hr runs an average 5 hours/day for 30 days: 60,000 × 5 × 30 = 9,000,000 BTU = 90 therms. At $1.20/therm that is $108.00 of gas, plus a $12 fixed charge = $120.00 for the month. Converting 90 therms back: 90 ÷ 1.037 ≈ 86.8 ccf, or 9,000,000 BTU, or about 247.9 m³. This is why a cold snap that doubles furnace runtime roughly doubles the variable part of your bill but leaves the fixed charge unchanged.

Real-World Use

Use this to sanity-check a utility bill, compare a gas vs. electric appliance on a true energy-cost basis, or budget seasonal heating. To compare with electricity, convert: 1 therm = 29.3 kWh of energy, but a gas furnace at 80–95% efficiency versus a heat pump at 250–400% effective efficiency changes the real cost comparison dramatically - compare delivered heat, not raw energy.

Common Mistakes

Treating ccf and therm as identical. They differ by the ≈ 1.037 heat-content factor, and your local factor may vary ± a few percent - check the bill.

Forgetting the fixed charge. Customer/service charges are flat regardless of usage and dominate a low-usage summer bill.

Using nameplate BTU as actual draw. A modulating or thermostatically cycled appliance rarely runs at full input continuously.

Ignoring delivery vs. supply. Deregulated markets split the per-therm price into a supply rate and a delivery rate; sum both.

Limitations

Results assume a constant price per therm; tiered or seasonal rate blocks, demand charges, taxes, and riders are not modeled - add them to the fixed-charge field as an approximation. Heating value varies slightly by region and over time. Appliance estimates assume the unit runs at its full rated input for the entered hours, which overstates usage for modulating furnaces and tankless water heaters. For precise budgeting, reconcile against 12 months of actual meter reads.

Natural Gas Cost Calculator

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