How We Calculate Propane Prices
The full methodology behind every price, calculator estimate, and savings recommendation on this site. We show our work so you can sanity-check ours and run your own.
Where the price data comes from
The EIA publishes a weekly residential propane survey covering 23 reporting states from October to March, plus monthly data for the full year. We pull this through the EIA Open Data API and use it as our anchor for state and regional averages. PADD (Petroleum Administration for Defense District) regional data fills in non-reporting states using a regional adjustment factor.
We sample retail rates from regional and national suppliers across 30+ markets each month — AmeriGas, Suburban, Ferrellgas, plus regional cooperatives. These do not replace EIA but are used to sanity-check directional movement and to surface supplier markup ranges that EIA does not capture.
When readers submit anonymised fill receipts, those are used to validate state-level averages and surface county-level outliers (rural premium, supplier monopoly markets). Submitted data is never used to identify individuals and is only published in aggregate.
How the calculator works
The Winter Cost Calculator on the homepage and the standalone calculator at /calculator use the same engine. The output is your annual propane cost, fills required, and how you compare to the national average. Here is the math:
Multipliers we use
| Variable | Range | Source |
|---|---|---|
| Climate (mild / moderate / cold) | 0.7 / 1.0 / 1.4 | Heating-degree-day data, NOAA |
| Home size (500 to 5,000 sqft) | 0.7 to 1.5 | DOE residential energy use survey |
| Tank fill rule | 80% of nominal | NFPA 58 safety standard |
| Furnace base usage | 1,000 gal/yr (2,000 sqft, moderate) | Industry standard 0.5-0.6 gal/sqft/yr |
| Water heater base usage | 250 gal/yr | DOE energy use estimates |
| Cooking range base usage | 42 gal/yr | DOE energy use estimates |
| Standby generator base usage | 50 gal/yr typical | Generator manufacturer specs |
| Pool/spa heater base usage | 500 gal/yr seasonal | Pool industry usage data |
These are estimates. Your actual usage depends on insulation quality, thermostat behaviour, appliance age, and a dozen other factors no calculator can know. Treat the result as a planning baseline, not a forecast.
Update cadence
EIA prices refreshed weekly. State-level data, national averages, and the Winter Cost Calculator output update every Monday.
EIA prices refreshed monthly. We backfill missing weekly data using PADD regional movement.
Every guide includes a "Last verified" stamp. We re-review against current data before each heating season and any time a reader flags a stale figure.
When we change how a number is calculated (multiplier change, new data source, different rounding), we note it here and version the change.
Editorial standards
- Independence. Pricing data, supplier comparisons, and product recommendations are never paid placements. Where a link earns us a referral fee, it is labelled.
- Sourcing. Numerical claims (price, capacity, savings figures) reference EIA, DOE, NFPA, or specific supplier quote dates. Subjective claims (best, worst, recommended) are framed as our opinion based on the underlying numbers.
- Corrections policy. We fix factual errors within 48 hours of being notified. Material corrections are noted at the bottom of the affected page.
- AI use. We use Claude and other LLMs to draft, summarise, and check our writing. Every published page is reviewed and edited by a human editor before going live. AI-only output never ships.
- Reader privacy. Reader-submitted fill receipts and form responses are anonymised before any aggregation. We do not sell, share, or rent reader contact data.
Honest limitations
What this site is good at: state-level price ranges, household-level cost estimates, fuel comparison logic, fill timing, and savings strategy.
What it is not good at: forecasting next month's wholesale propane price, naming the cheapest supplier in your specific zip code, or telling you what a contract you have not yet signed will end up costing.
For zip-level pricing decisions, get three written quotes from local suppliers — that is still the only reliable way to find the cheapest delivered price in your area. Our calculators help you sanity-check those quotes against the regional baseline.
Read next
Who runs the site, why it exists, what we publish.
Apply this methodology to your home, state, and tank.
The state-level dataset built on this methodology.
Founder of Digital Signet, an independent research firm that builds data-led pricing and decision tools for US homeowners. PropaneCostPerGallon.com is built from the EIA's weekly residential propane survey, supplier-quoted retail rates, and real fill-up receipts collected from readers.