Natural Gas Bill Calculator

Calculate monthly natural gas bill from therms used and rate.

By Konstantin Iakovlev · Updated September 2026 · Source: EIA — Natural Gas Prices, U.S. residential price (monthly, data through June 2026)

$
$

Monthly Bill

$12.00

Annual Cost

$144.00

Breakdown

Usage Cost$0.00
Service Charge$12.00
Monthly Total$12.00
Annual Total$144.00
Equivalent Electric Cost$0.00

Use the Natural Gas Bill Calculator above to calculate your results. Enter your values and see instant results — all calculations run in your browser.

Disclaimer: This calculator is for informational purposes only. Results are estimates based on the information you provide and the assumptions described on this page.

How It Works

Estimating a monthly natural gas bill comes down to how much energy your home burns and what your utility charges for it. That math matters for budgeting and for spotting where you might trim usage. EIA's U.S. average residential price was $15.34 per thousand cubic feet in 2025, about $1.48 per therm, and it swings with the season: $13.96 in January 2026 and $24.09 in June 2026, the latest month published.

The underlying formula is simple: Total Bill = (Therms Used * Rate per Therm) + Fixed Monthly Charges. A therm reflects the energy content of the gas your meter records as you consume it. The rate per therm is what your utility bills for each one, and it is often tiered or tied to market swings. Fixed monthly charges sit on top regardless of usage, covering administrative and infrastructure costs.

People routinely leave the fixed monthly charges out of their estimate, and that omission can throw off the total considerably. Tiered pricing is another wrinkle: cross a certain usage threshold and your per-therm rate may jump. For the most accurate picture, pull your latest bill or check your provider's website for current rates and any surcharges that apply to your account.

Example: Estimating a Winter Month's Natural Gas Bill

  1. 1 Input: you used 85 therms in a winter month. Your utility charges $1.45 per therm and a fixed monthly service charge of $18.50.
  2. 2 Calculation: 85 therms × $1.45 = $123.25 for usage, plus the $18.50 service charge = $141.75.
  3. 3 Result: the bill for that month is about $141.75. The calculator's annual line multiplies it by 12 ($1,701.00), which overstates the year for a home that burns far less gas in summer, so average several months' bills for a yearly figure.
  4. 4 The Equivalent Electric Cost line prices the same energy as electricity: 85 therms × 29.3 kWh per therm × $0.16 = $398.48.

Source: EIA — Natural Gas Prices, U.S. residential price (monthly, data through June 2026) · Last updated: September 2026

Frequently Asked Questions

What is the average natural gas bill per month?
It depends heavily on the season and on whether gas heats your home. At EIA's 2025 U.S. average residential price of about $1.48 per therm ($15.34 per thousand cubic feet), 50 therms, the calculator's placeholder usage, costs about $74; winter use in a gas-heated home is usually well above that, and summer use for water heating and cooking well below.
How much does natural gas cost per therm?
EIA's U.S. average residential price was $15.34 per thousand cubic feet in 2025, about $1.48 per therm at EIA's conversion of 10.37 therms per Mcf. Among states with 2025 data, averages ran from $7.69 in Idaho (about $0.74 per therm) to $25.48 in Florida (about $2.46) and $52.38 in Hawaii (about $5.05), and the national figure moves with the season, from $13.96 in January 2026 to $24.09 in June 2026. Your bill may also carry a fixed monthly customer charge, which the calculator takes separately.
How many therms does a gas furnace use per month?
It depends on climate, house size, insulation and thermostat settings, so your own winter bills are the best guide. Efficiency matters too: AFUE is the share of the fuel's energy a furnace turns into heat over a year, so a 95% AFUE furnace uses about 16% less gas than an 80% AFUE model for the same heat (80 ÷ 95 = 0.84).

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