Convert US gallons to oil barrels and back with high precision. Choose decimal places or significant figures, copy results instantly, and build shareable permalinks. Supports unit hints, rounding control, and input validation for reliable engineering workflows. Ideal for petroleum economics, storage planning, and trading calculations across labs, terminals, and classrooms. Includes 42-gallon standard reference and quick inverse conversion helpers too.
| Gallons | Barrels (bbl) |
|---|
| Barrels (bbl) | Gallons |
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This converter is designed to answer the most common question in oil trading, brewing, and logistics: “How many barrels is n gallons?” The twist is that the term barrel does not always mean the same thing. An oil barrel is standardized at 42 US gallons. In brewing you will also find the US beer barrel at 31 US gallons, and in older US liquid‑measure references, a US liquid barrel defined as 31.5 US gallons. In the UK brewing context, a beer barrel is 36 imperial gallons—a different gallon size from the US gallon. That is why a high‑quality converter must let you choose both the gallon unit and the barrel type.
Start by entering your gallon value and selecting the gallon unit (US or Imperial). Then choose a barrel type. The calculator converts everything through liters to avoid ambiguity: it multiplies your gallons by the appropriate liters‑per‑gallon factor, then divides by the liters represented by the chosen barrel type. For oil and US barrels the base gallon is US; for the UK beer barrel the base gallon is the imperial gallon. The result updates instantly and is also shown in liters for quick cross‑checks.
If you need the reverse, switch to “Barrels → Gallons,” enter barrels (bbl), select the same barrel type, and choose whether you want the output in US or Imperial gallons. The copy buttons allow you to paste results or formulas directly into emails, reports, or spreadsheet models. The quick lookups summarize popular values—like 1, 5, 10, 42, 55, 100, and 1000 gallons—so you can get answers at a glance.
| Barrel type | Gallons per barrel | Liters per barrel (approx.) | Simple forward formula |
|---|---|---|---|
| Oil barrel | 42 US gal | ~158.99 L | bbl = US gallons ÷ 42 |
| US beer barrel | 31 US gal | ~117.35 L | bbl = US gallons ÷ 31 |
| US liquid barrel | 31.5 US gal | ~119.24 L | bbl = US gallons ÷ 31.5 |
| UK beer barrel | 36 imperial gal | ~163.66 L | bbl = Imperial gallons ÷ 36 |
Notes on precision: we show up to six decimal places on barrels because shipping and trading sometimes require fractional barrels; you may round to fewer decimals for consumer contexts. Liter equivalents are rounded to two decimals by default. Internally, the converter uses the SI‑exact factors 1 US gal = 3.785411784 L and 1 imp gal = 4.54609 L to maintain consistency across all paths, which is why results stay coherent when you switch units and barrel types.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.