Three different numbers, three different stories
The Strategic Petroleum Reserve is an emergency stockpile of crude oil. Commercial crude inventories are a separate measure; use the series excluding the SPR when comparing commercial stocks. Gasoline inventories describe a refined product. These are not interchangeable totals, and none is the same thing as underground proved oil reserves.
Read the week, not just the headline
The EIA Weekly Petroleum Status Report provides inventory and operating data. When reading a change, check the observation week, release date, units, geography, and whether a correction was issued. A national inventory change is not a local station quote. This article is an evergreen guide, not a report of a new inventory decline.
Do not invent a cents-per-gallon forecast
A reserve release or inventory draw is context, not a formula giving an exact future pump price. Instead, choose explicit price scenarios. For example, 12 gallons weekly with a hypothetical 70¢ increase adds $36.40 per average month. A 40¢ decrease would reduce the same planned expense by $20.80 monthly.
Follow the evidence, then test your plan
Use official EIA data for inventories and DOE information for the SPR. Ask what changed and which series was measured. Then use your own gallons and frequency in Piggy. The calculator does not claim to predict oil markets or tell you how to invest.
Try this with your numbers
The calculator opens with this article's hypothetical example. Your budget is not a headline—change the prices, quantity and frequency.
Test your plan with PiggySources and coverage
This guide does not quote a current station price or report a fresh inventory change. Follow the source to check its latest observation period and publication date.
A little clarity, not a guarantee
Projections are not recorded spending or confirmed savings. No national average or future price is inferred. The web calculator does not upload receipts, send family requests, or update the iPhone app.