Eight browser-side calculators for oil & gas — no data leaves your device. Convert crude volumes by API gravity, estimate refining margins, translate between energy-content units, size a storage tank, value a futures contract, split a barrel into products, test well economics and total up fuel taxes.
Barrels ↔ gallons, litres, cubic metres & tonnes — mass depends on API gravity.
Formula: SG = 141.5 / (°API + 131.5); 1 bbl = 42 US gal = 158.987 L; tonnes = litres × SG × 0.999 ÷ 1000. WTI ≈ 39.6°API, Brent ≈ 38°API, Dubai ≈ 31°API.
Gross refining margin from crude & product prices.
Formula: 3:2:1 crack = [(2 × gasoline + 1 × distillate) × 42 − 3 × crude] ÷ 3, in $/bbl. Products are quoted $/gallon and multiplied by 42 to reach $/barrel. This is a gross margin — it excludes operating, energy and capital costs.
Heating value across fuels & energy units (barrel of oil equivalent).
Reference: 1 bbl crude ≈ 5.8 MMBtu; 1 MMBtu = 1.055 GJ = 0.293 MWh = 10 therms = 1 Mcf gas (≈1.036). Approximate EIA heating-value conversions — actual energy content varies by crude grade and fuel spec.
Storage tank or vessel dimensions to barrels, gallons, litres & tonnes.
Formula: cylinder V = π r² h; rectangular V = l × w × h. 1 bbl = 5.614583 ft³ = 42 US gal. Mass uses the same API-gravity density as the converter above. This is total geometric capacity — working capacity is lower, since tanks are not filled to the roof.
Notional value, tick value and P&L for energy futures.
Formula: notional = price × contract size × contracts. CL and BZ are 1,000 barrels with a $0.01 tick worth $10; NG is 10,000 MMBtu ($0.001 tick = $10); RB and HO are 42,000 gallons ($0.0001 tick = $4.20). Notional is not margin — exchanges require only a few percent of this to hold a position, which is exactly why futures amplify both gains and losses.
Split a barrel of crude into its finished products.
Note: defaults are roughly the US average yield. Refineries produce MORE than a barrel of product per barrel of crude — cracking adds volume, so total yield runs about 102–104%. That "processing gain" is real, not an error. Remaining percent is booked as residual fuel, petrochemical feedstock, asphalt and refinery losses.
The oil price a new well needs to pay back its drilling cost.
Formula: break-even = (capex ÷ EUR + opex) ÷ (1 − royalty & severance). EUR is entered in thousands of barrels. This is a simplified half-cycle break-even: it ignores the time value of money, land and seismic costs already sunk, and the steep first-year decline of a shale well. Published basin break-evens use full discounted cash flow and will differ.
Federal plus state fuel tax on a fill-up and over a year.
Formula: tax = (federal 18.4¢ + state ¢) × gallons. "Miles/year ÷ MPG" is your annual gallons — 500 is roughly 12,000 miles at 24 MPG. State rates here are the hand-curated highest and lowest ten from gas tax by state and are approximate; states adjust them, often each January or July. Sales tax, where a state charges it on fuel, is not included.
These calculators use standard EIA/industry conversion factors and are for estimation only. For live prices to plug in, see crude & product prices, retail gasoline and diesel.