Barrels per day (bbl/d) — the unit that runs global oil markets
1 million bbl/d = 1,839 m³/h = 511 L/s. The unit is quaint; the numbers it produces are enormous.
Oil production and consumption are quoted almost universally in barrels per day (bbl/d, bpd, or b/d), even in metric countries. A supertanker carrying 2 million bbl is holding 318,000 m³ of crude — the numbers work equally well in either unit, but bbl/d dominates every OPEC bulletin, EIA weekly report and futures contract.
The exact factors
1 bbl = 158.987 L = 0.158987 m³ > 1 bbl/d = 6.6245 L/hr = 1.84 × 10⁻³ m³/hr > 1 million bbl/d (Mbbl/d) = 158,987 m³/d = 1,839 m³/h = 511 L/s > 1 bbl/d ≈ 0.05 tonnes/day (medium crude)
Global anchors
Saudi Arabia production capacity: ~12 Mbbl/d. US production 2024: 13.2 Mbbl/d. Global consumption 2024: ~102 Mbbl/d. Strategic petroleum reserves: US SPR maximum 727 million bbl; typical release rate 1 Mbbl/d for 6 months. A single 500,000 bbl/d refinery processes about one supertanker every four days.
Refinery yield
A barrel of crude yields typically: 20 gal gasoline, 10 gal diesel, 4 gal jet fuel, 8 gal other. That is 42 gal in = 42 gal out — the volumetric expansion of cracking cancels the reduction from residuals. Mass is conserved; volume is not. This is why refinery output is quoted in bbl even when input is in tonnes.
Worked example — a country's 3 Mbbl/d import bill
3 Mbbl/d × 365 = 1,095 Mbbl/year × $80/bbl = $87.6 billion. Physical volume: 173.8 million m³ = a cube 558 m on a side, or 25 supertankers per week. This is roughly Japan's or Korea's typical oil import rate.
The five-second recap
1 Mbbl/d = 1,839 m³/h = 511 L/s. 1 bbl = 159 L. OPEC, EIA and every futures contract quote bbl/d — no matter where the country sits on the metric map.
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FAQ
How many bbl in a supertanker?+
A VLCC (Very Large Crude Carrier) holds 2 million bbl. An ULCC (Ultra Large) holds 3 million bbl. About 4.5% of world demand sits in transit on tankers at any moment.
Is bbl the same as an oil drum?+
The 42-gal oil barrel is a pricing unit. The physical 55-gal drum is a container. They share a lineage but are not interchangeable — a 55-gal drum holds 1.31 oil bbl.
Why 42 gallons?+
Adopted in Pennsylvania in 1866, matching the tierce (a wine cask). 42 gal was a size one man could handle rolling across a dock.
This article was written by The Turbo Unit Converter engineering desk (Oil & gas engineering) and last reviewed on 2026-06-30 against NIST SP 811 and the BIPM SI Brochure. Read our full editorial policy.