bbl to ft³ Converter — Oil Barrels, Beer Barrels & US Liquid Barrels
Convert barrels to cubic feet instantly with our free bbl to ft3 calculator. Supports all major barrel types: US oil barrels (42 gal), US beer barrels (31 gal), US liquid barrels (31.5 gal), and UK beer barrels (36 imp gal). Whether you're converting oil barrels to cubic feet for tank design, beer barrels to cubic feet for brewery planning, or bbls to cubic feet for chemical storage, select your barrel type and get instant results. 1 oil barrel = 5.6146 ft³. Need the reverse? Use the ft³ → bbl tab below.
Oil Barrel
1 oil bbl = 5.6146 ft³
Beer Barrel
1 beer bbl = 4.1448 ft³
Oil Formula
× 5.6146
Select Barrel Type
Convert barrels into cubic feet for the currently selected barrel standard.
Cubic Feet (ft³)
5.6146 ft³
US Oil Barrels (42 gal each)
1 bbl × 5.61458 = 5.6146 ft³
Formula: ft³ = bbl × 5.61458
(1 US Oil Barrel = 42 US gallons)
US gallons
42.00 gal
Liters
158.987 L
Cubic Meters
0.1590 m³
Cubic Inches
9,702 in³
💡 Tip
1 oil barrel = 42 US gallons = 5.6146 ft³. The 42-gallon standard has been used since the 1860s Pennsylvania oil boom.
Visualizing barrel volumes as real-world spaces.
5.6146 ft³
A box roughly 2 ft × 1.5 ft × 1.87 ft — about the size of a large microwave oven or a medium suitcase standing upright.
42 US gallons = 158.99 L = 5.6146 ft³
1 bbl = 5.6146 ft³
10 bbl = 56.15 ft³
100 bbl = 561.5 ft³
Industry: Petroleum, crude oil, and refined products
4.1448 ft³
A box roughly 1.75 ft × 1.5 ft × 1.58 ft — slightly smaller than a standard keg, about the size of a large carry-on suitcase.
31 US gallons = 117.35 L = 4.1448 ft³
1 bbl = 4.1448 ft³
½ bbl = 2.0724 ft³
¼ bbl = 1.0362 ft³
⅙ bbl = 0.6908 ft³
Industry: US craft brewing and TTB reporting
4.2109 ft³
Very similar to a US beer barrel: a box roughly 1.75 ft × 1.5 ft × 1.61 ft. It is only about 1.6% larger than a US beer barrel.
31.5 US gallons = 119.24 L = 4.2109 ft³
1 bbl = 4.2109 ft³
10 bbl = 42.109 ft³
100 bbl = 421.09 ft³
Industry: Cranberries, molasses, and some chemicals
5.7779 ft³
Almost the same size as a US oil barrel: a box roughly 2 ft × 1.5 ft × 1.93 ft. It is about 2.9% larger than a US oil barrel.
36 imperial gallons = 163.66 L = 5.7779 ft³
1 bbl = 5.7779 ft³
½ bbl = 2.8890 ft³
¼ bbl = 1.4445 ft³
Industry: UK brewing and HMRC duty calculations
| Barrel Type | Gallons | Liters | Cubic Feet |
|---|---|---|---|
| US Oil Barrel | 42 US gal | 158.99 L | 5.6146 ft³ |
| UK Beer Barrel | 36 imp gal | 163.66 L | 5.7779 ft³ |
| US Liquid Barrel | 31.5 US gal | 119.24 L | 4.2109 ft³ |
| US Beer Barrel | 31 US gal | 117.35 L | 4.1448 ft³ |
⚠️ "bbl" is ambiguous. Always confirm barrel type before converting.
Formula: ft³ = bbl × 5.6146
Formula: ft³ = beer bbl × 4.1448
Select barrel type to see the corresponding ft³ values.
| Barrels (bbl) | Cubic Feet (ft³) | US Gallons | Common Use |
|---|---|---|---|
| 0.5 bbl | 2.807 ft³ | 21 gal | Half barrel ref |
| 1 bbl | 5.6146 ft³ | 42 gal | 1 oil barrel ⭐ |
| 2 bbl | 11.229 ft³ | 84 gal | Small vessel |
| 5 bbl | 28.073 ft³ | 210 gal | Small tank |
| 10 bbl | 56.146 ft³ | 420 gal | Storage vessel |
| 25 bbl | 140.36 ft³ | 1,050 gal | Medium tank |
| 50 bbl | 280.73 ft³ | 2,100 gal | Tank truck |
| 100 bbl | 561.46 ft³ | 4,200 gal | Small storage tank |
| 250 bbl | 1,403.6 ft³ | 10,500 gal | Medium tank |
| 500 bbl | 2,807.3 ft³ | 21,000 gal | Large tank |
| 1,000 bbl | 5,614.6 ft³ | 42,000 gal | Tank farm unit |
| 5,000 bbl | 28,072.9 ft³ | 210,000 gal | Large storage tank |
| 10,000 bbl | 56,145.8 ft³ | 420,000 gal | Major tank farm |
US Oil Barrel (42 US gal): ft³ = bbl × 5.61458 bbl = ft³ × 0.178107 US Beer Barrel (31 US gal): ft³ = bbl × 4.14479 bbl = ft³ × 0.241365 US Liquid Barrel (31.5 US gal): ft³ = bbl × 4.21094 bbl = ft³ × 0.237483 UK Beer Barrel (36 imp gal): ft³ = bbl × 5.77792 bbl = ft³ × 0.173072
All barrel-to-ft³ conversions go through gallons: Step 1: Know ft³ per gallon 1 US gallon ≈ 0.133681 ft³ 1 imperial gallon ≈ 0.160544 ft³ Step 2: Multiply by barrel size US oil bbl: 42 × 0.133681 = 5.61458 ft³ US beer bbl: 31 × 0.133681 = 4.14479 ft³ US liq bbl: 31.5 × 0.133681 = 4.21094 ft³ UK beer bbl: 36 × 0.160544 = 5.77792 ft³ Step 3: Reverse when needed 1 ÷ 5.61458 = 0.178107 bbl/ft³ 1 ÷ 4.14479 = 0.241365 bbl/ft³
1 US gallon = 231 in³ by US definition 1 ft³ = 1,728 in³ So 1 ft³ ≈ 7.48052 US gallons That gives the standard engineering value used here: 1 US oil bbl ≈ 42 ÷ 7.48052 = 5.61458 ft³ For planning, reporting, and equipment sizing, the rounded values on this page are typically more than sufficient.
A petroleum company needs a storage tank to hold 500 oil barrels. What size tank in cubic feet do they need?
Step 1: Formula: ft³ = bbl × 5.61458
Step 2: ft³ = 500 × 5.61458
Step 3: ft³ = 2,807.3
Result: 500 oil bbl = 2,807.3 ft³
If the tank is cylindrical with a 12 ft diameter, height = 2,807.3 ÷ (π × 6²) = 24.8 ft, so a 12 ft diameter × 25 ft tall tank is a practical target.
A craft brewery has 6 × 15 bbl fermenters. How much floor space do they need if each tank is 6 ft tall?
Step 1: ft³ per fermenter = 15 × 4.14479 = 62.17 ft³
Step 2: Total volume = 6 × 62.17 = 373.0 ft³
Step 3: Floor area per tank = 62.17 ÷ 6 = 10.36 ft²
Step 4: Total floor area = 6 × 10.36 = 62.2 ft²
Add roughly 50% clearance for access and service space, so plan for about 93 ft² minimum and round up to 100 ft².
A UK pub needs to store 20 UK beer barrels. What cellar volume is required?
Step 1: Formula: ft³ = bbl × 5.77792
Step 2: ft³ = 20 × 5.77792
Step 3: ft³ = 115.56
Result: 20 UK barrels = 115.56 ft³
Add 40% for access, cooling equipment, and CO₂ cylinders: 115.56 × 1.4 = 161.8 ft³, so a 6 ft × 9 ft × 3 ft cellar would cover the target.
Six industry scenarios where bbl to ft³ conversion is essential.
Civil and mechanical engineers often receive oil capacity requirements in barrels, then have to size the actual steel or concrete structure in cubic feet.
Client spec: 1,000 bbl crude oil storage. Convert: 1,000 × 5.6146 = 5,614.6 ft³. Always add 5-10% freeboard above the calculated volume for safety and thermal expansion.
Brewers buy, compare, and report production in barrels, but building permits, room layouts, and HVAC designs still rely on cubic feet and square feet.
Common brewery systems: 1 bbl = 4.14 ft³ 3 bbl = 12.43 ft³ 7 bbl = 29.01 ft³ 15 bbl = 62.17 ft³ 30 bbl = 124.3 ft³
Chemical facilities frequently specify vessel capacity in barrels, while secondary containment, civil drawings, and safety systems are designed in cubic feet.
Example: 50 liquid barrels of solvent = 50 × 4.2109 = 210.5 ft³. At 110% containment, the berm must hold about 231.6 ft³.
Auditors and operations teams often cross-check barrel-based production or inventory records against tank charts and physical measurements in cubic feet.
If a tank chart shows 3,200 ft³, then 3,200 × 0.17811 = 569.9 oil bbl. If the invoice says 580 bbl, the 1.7% gap deserves review.
Liquid cargo is often traded in barrels but vehicle, trailer, railcar, and hold capacities are commonly checked in cubic feet or cubic meters.
Typical oil references: Tanker truck ≈ 180 bbl = 1,011 ft³ Rail tank car ≈ 700 bbl = 3,930 ft³ Barge ≈ 10,000 bbl = 56,146 ft³
Homeowners and HVAC contractors sometimes need to convert barrel-style liquid references into cubic feet for enclosure planning and permit paperwork.
A 500 gallon residential tank is about 11.905 oil bbl and about 66.84 ft³. Heating oil usually follows liquid volume conventions, so always verify the exact unit used.
Click any card to use this value in the calculator above.
These quick cards use US oil barrel references by default. Your currently selected barrel type in the calculator stays unchanged.
Common questions about converting barrels to cubic feet.
It depends on the barrel type:
US Oil Barrel (42 US gal): 1 bbl = 5.6146 ft³ US Beer Barrel (31 US gal): 1 bbl = 4.1448 ft³ US Liquid Barrel (31.5 US gal): 1 bbl = 4.2109 ft³ UK Beer Barrel (36 imp gal): 1 bbl = 5.7779 ft³
For petroleum and oil & gas contexts, use the US oil barrel. For US brewing, use the 31-gallon beer barrel.
Quick mental reference: Oil barrel ≈ 5.6 ft³ Beer barrel ≈ 4.1 ft³
Multiply the number of oil barrels by 5.6146:
ft³ = bbl × 5.6146
Examples: • 1 bbl × 5.6146 = 5.6146 ft³ • 10 bbl × 5.6146 = 56.146 ft³ • 100 bbl × 5.6146 = 561.46 ft³ • 1,000 bbl × 5.6146 = 5,614.6 ft³
Reverse: 100 ft³ × 0.17811 = 17.811 bbl
1 US oil barrel = 5.6146 cubic feet.
This comes from: 1 US oil barrel = 42 US gallons 1 US gallon ≈ 0.133681 ft³ 42 × 0.133681 = 5.61458 ft³
Visualize it as something around the size of a large microwave oven or a medium suitcase standing upright.
Common oil-barrel references: 10 bbl = 56.15 ft³ 100 bbl = 561.5 ft³ 1,000 bbl = 5,615 ft³
For US beer barrels: ft³ = bbl × 4.1448
Examples: • 1 bbl = 4.1448 ft³ • 7 bbl = 29.013 ft³ • 15 bbl = 62.172 ft³ • 30 bbl = 124.34 ft³
For UK beer barrels: ft³ = bbl × 5.7779
US and UK beer barrels are different sizes, so always confirm the system before converting.
A US half-barrel keg (15.5 US gallons) = 2.0724 ft³.
That is the most common commercial keg size in the US.
Other US keg references: Sixtel (⅙ bbl) = 0.6908 ft³ Pony keg (¼ bbl) = 1.0362 ft³ Half-barrel (½ bbl) = 2.0724 ft³ Full barrel (1 bbl) = 4.1448 ft³
A half-barrel takes up about the space of a large carry-on suitcase.
US Oil Barrel: 42 US gallons = 158.99 L = 5.6146 ft³ US Beer Barrel: 31 US gallons = 117.35 L = 4.1448 ft³ UK Beer Barrel: 36 imperial gallons = 163.66 L = 5.7779 ft³
Key differences: • US and UK gallons are not the same size • A UK beer barrel is slightly larger than a US oil barrel • The UK firkin = ¼ UK barrel = 1.4445 ft³ • The UK kilderkin = ½ UK barrel = 2.8890 ft³
Step 1: Convert bbl to ft³ ft³ = bbl × 5.6146 (oil) or × 4.1448 (beer)
Step 2: Choose a diameter D in feet Height = ft³ ÷ (π × (D/2)²)
Example: 100 oil barrels with a 10 ft diameter tank: 100 × 5.6146 = 561.46 ft³ h = 561.46 ÷ (π × 5²) h = 561.46 ÷ 78.54 h = 7.15 ft
So a 10 ft diameter × 7.15 ft tall cylinder holds about 100 oil barrels. Add freeboard if the tank should never be filled to the absolute top.
For the reverse-direction page, use Cubic Feet to Barrels.
From cubic meters to cubic feet, compare volumes quickly with clear formulas and fast results.