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.
Source: EIA SHOPP residential propane survey. Current data is the final release of the 2025/26 heating season (week ending 30 March 2026). EIA pauses weekly publication April-September; next release expected October 2026. Refreshed 26 May 2026.
Where the price data comes from
Source: EIA State Heating Oil and Propane Program (SHOPP), the residential propane price series. SHOPP publishes state-level weekly prices during the heating season (October to March) only; outside that window EIA does not collect state-level weekly residential propane data. State pages are reviewed against the latest SHOPP release each month, which during off-season means displaying the final release of the previous season (typically late April) until the new season opens. The headline US-average figure on the home page comes from the EIA weekly residential propane series (week ending 30 March 2026, the final release of the 2025/26 heating season; $2.67/gal). EIA does not publish weekly residential propane between April and September; the next release is expected October 2026. Where EIA does not publish a direct state value within a given week, the affected page indicates that explicitly.
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 SHOPP publishes state-level weekly residential propane prices Monday through March. State pages are reviewed against the latest release each month.
EIA SHOPP does not collect state-level weekly prices outside the heating season. The final release of one season (typically late April) is the latest available state data until the next season opens (typically early October). State pages display that final-of-season figure during off-season; the LastVerified date reflects the actual EIA release date, not today.
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. Digital Signet uses large language models (Claude, GPT-4, others) to draft and quality-check content via the Signet autonomous-dev-team methodology. Editorial direction is set by humans; drafting is mostly automated; review depth scales with the site's tier.
- Reader privacy. Where forms or contact channels collect reader data, that data is anonymised before any aggregation. We do not sell, share, or rent reader contact information.
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.