Enter fuel data
Choose a mode, enter known values, select units, and calculate. Preset density values remain editable for real product data.
Fuel density comparison
These reference values are approximate. Specifications, composition, temperature, pressure, and batches can produce different measurements.
| Fuel | Reference density | Approximate range | kg per litre | lb per US gallon | Approx. SG | Approx. API | Expansion β |
|---|---|---|---|---|---|---|---|
| Gasoline / petrol Typical automotive gasoline blend. |
745.0 kg/m³ at 15°C | 700–780 kg/m³ | 0.7450 | 6.217 | 0.7457 | 58.26° | 0.000950/°C |
| Automotive diesel Typical road diesel near the reference temperature. |
832.0 kg/m³ at 15°C | 800–870 kg/m³ | 0.8320 | 6.943 | 0.8327 | 38.42° | 0.000830/°C |
| Biodiesel (B100) Density varies with feedstock and specification. |
880.0 kg/m³ at 15°C | 860–900 kg/m³ | 0.8800 | 7.344 | 0.8808 | 29.15° | 0.000750/°C |
| Kerosene General kerosene estimate. |
800.0 kg/m³ at 15°C | 775–840 kg/m³ | 0.8000 | 6.676 | 0.8007 | 45.22° | 0.000900/°C |
| Jet A Approximate aviation turbine fuel density. |
804.0 kg/m³ at 15°C | 775–840 kg/m³ | 0.8040 | 6.710 | 0.8047 | 44.34° | 0.000990/°C |
| Jet A-1 Approximate; use dispatch documentation for flight operations. |
804.0 kg/m³ at 15°C | 775–840 kg/m³ | 0.8040 | 6.710 | 0.8047 | 44.34° | 0.000990/°C |
| Aviation gasoline (Avgas) Approximate aviation gasoline value. |
720.0 kg/m³ at 15°C | 690–750 kg/m³ | 0.7200 | 6.009 | 0.7206 | 64.85° | 0.001100/°C |
| Heating oil Representative middle-distillate value. |
850.0 kg/m³ at 15°C | 820–900 kg/m³ | 0.8500 | 7.094 | 0.8508 | 34.82° | 0.000800/°C |
| Marine diesel oil Marine grades span a broad density range. |
890.0 kg/m³ at 15°C | 850–930 kg/m³ | 0.8900 | 7.427 | 0.8908 | 27.35° | 0.000720/°C |
| Heavy fuel oil High-viscosity residual fuel estimate. |
970.0 kg/m³ at 15°C | 930–1010 kg/m³ | 0.9700 | 8.095 | 0.9709 | 14.25° | 0.000650/°C |
| Ethanol Approximate anhydrous ethanol value. |
789.3 kg/m³ at 20°C | 780–800 kg/m³ | 0.7893 | 6.587 | 0.7907 | 47.45° | 0.001090/°C |
| Methanol Approximate pure methanol value. |
791.8 kg/m³ at 20°C | 785–800 kg/m³ | 0.7918 | 6.608 | 0.7932 | 46.89° | 0.001180/°C |
| E10 gasoline Gasoline containing about ten percent ethanol. |
750.0 kg/m³ at 15°C | 710–790 kg/m³ | 0.7500 | 6.259 | 0.7507 | 57.00° | 0.000980/°C |
| E85 fuel Seasonal ethanol content changes actual density. |
785.0 kg/m³ at 15°C | 760–810 kg/m³ | 0.7850 | 6.551 | 0.7857 | 48.59° | 0.001050/°C |
| Liquefied petroleum gas Composition and pressure strongly affect liquid LPG density. |
540.0 kg/m³ at 15°C | 500–590 kg/m³ | 0.5400 | 4.507 | 0.5405 | 130.30° | 0.002500/°C |
| Light crude oil Crude oils vary widely by origin. |
830.0 kg/m³ at 15°C | 780–870 kg/m³ | 0.8300 | 6.927 | 0.8307 | 38.83° | 0.000820/°C |
| Heavy crude oil Representative heavy-crude estimate. |
950.0 kg/m³ at 15°C | 900–1010 kg/m³ | 0.9500 | 7.928 | 0.9509 | 17.31° | 0.000700/°C |
Formula used
Core density formulas
Mass: m = ρ × V
Volume: V = m / ρ
Internally, mass is converted to kilograms and volume to cubic metres. The result is then converted into the requested display unit.
Specific gravity and API gravity
°API = 141.5 / SG60°F − 131.5
SG60°F = 141.5 / (°API + 131.5)
Specific gravity has no unit. API gravity is normally based on relative density at 60°F.
Temperature correction
V(T) = Vref × [1 + β(T − Tref)]
The calculator applies a linear volumetric expansion model. It treats mass as constant while volume and density change inversely.
Tank calculations
Cylinder: V = πr²L
Sphere: V = 4πr³/3
Ellipsoid: V = 4πabc/3
Fuel mass: m = ρ × Vfilled
Horizontal-cylinder and spherical tanks can use liquid depth. Other shapes use entered fill percentage.
How to use this calculator
- Select the calculation mode matching the quantity you need.
- Choose a fuel preset or select Custom fuel.
- Enter the known mass, volume, density, gravity, temperature, or tank dimensions.
- Check every input unit, especially US versus Imperial gallons.
- For temperature correction, confirm the measured, reference, and target temperatures.
- Replace the preset expansion coefficient with a verified product value when available.
- Select the output units and number formatting.
- Press Calculate fuel values. Review warnings before using the result.
- Copy, print, save as PDF, or export the calculation to CSV.
Understanding fuel density and practical measurement
What fuel density means
Fuel density describes how much mass is contained in a given volume. A density of 832 kilograms per cubic metre means one cubic metre of that fuel has a mass of about 832 kilograms under the stated conditions. The same value can be written as 0.832 kilograms per litre or 0.832 grams per millilitre. Density helps operators convert a delivery volume into mass, estimate vehicle payload, compare energy supplied by volume, and check whether a measured product is broadly consistent with its expected grade.
Why temperature changes the result
Most liquid fuels expand when warmed and contract when cooled. The number of fuel molecules does not increase during ordinary heating, so the mass remains nearly constant while the occupied volume changes. A warmer sample therefore usually has a lower density. Commercial fuel measurements often specify a standard reference temperature so quantities recorded in different climates can be compared consistently. Common references include 15°C, 20°C, and 60°F. This calculator uses an editable volumetric expansion coefficient for convenient estimates between temperatures.
The linear model is most useful across moderate temperature differences. Very broad ranges, pressurized liquids, volatile mixtures, phase changes, and unusual compositions may need more detailed equations or standardized correction tables. LPG is especially sensitive to composition, pressure, and temperature. Aviation, custody-transfer, taxation, and regulated transactions should rely on certified documentation, approved instruments, and the relevant industry standard rather than an informal estimate.
Density, specific gravity, and API gravity
Density includes units because it compares mass with volume. Specific gravity is a ratio between the fuel density and water density at a stated reference condition, so it is dimensionless. A specific gravity below one normally indicates a liquid lighter than water. API gravity is another petroleum scale derived from specific gravity at 60°F. Higher API gravity values indicate lighter petroleum liquids, while lower values indicate heavier products. The calculator provides both directions of conversion, but the reference condition must be understood before comparing reported values.
Improving measurement quality
Accurate calculations require accurate inputs. Confirm that weighing equipment is calibrated, tank dimensions reflect internal usable dimensions, and volume readings account for the tank orientation. Remove commas or ambiguous symbols from numeric entries. Record the sample temperature near the time of measurement. Use a hydrometer or digital density meter suitable for the product. Avoid trapped air, water contamination, sediment, and unrepresentative samples. For a fuel blend, use the certificate of analysis or supplier specification whenever possible.
Preset values on this page represent broad examples, not guaranteed specifications. Gasoline changes with season and blending components. Diesel varies by regional grade and biodiesel content. Crude oil can span a very wide density range. Even products sharing a trade name can differ between batches. Entering a laboratory or supplier value will usually produce a more useful mass, tank, or cost estimate than accepting a generic preset unchanged.
Using density for tank and transport planning
A tank’s geometric capacity gives volume, but vehicle and structural limits are often based on mass. Multiplying filled volume by density converts the liquid quantity into fuel mass. Adding the empty tank or container weight gives a loaded-weight estimate. This is useful for preliminary transport, lifting, storage, and inventory planning. Always keep operating fill limits, thermal expansion space, legal axle limits, structural ratings, and safety requirements separate from the calculator’s mathematical result.
For horizontal cylindrical and spherical tanks, liquid depth does not correspond linearly with volume. The calculator therefore uses curved-segment geometry when a fill depth is supplied. Rectangular, vertical cylindrical, custom-capacity, and ellipsoidal options use a fill fraction. Complex end caps, internal baffles, irregular bottoms, dead stock, pipework, and calibration offsets are not included. A certified tank strapping chart provides better inventory accuracy for commercial storage.
Frequently asked questions
What is a typical diesel density?
Road diesel is often roughly 800–870 kg/m³ near a standard reference temperature. Exact specifications depend on grade, location, biodiesel content, and test method.
How much does one litre of fuel weigh?
Multiply one litre, equal to 0.001 m³, by density in kg/m³. A fuel at 832 kg/m³ weighs about 0.832 kg per litre.
Are US and Imperial gallons interchangeable?
No. One US liquid gallon is about 3.785 litres, while one Imperial gallon is about 4.546 litres. Selecting the wrong gallon can create a substantial error.
Does fuel mass change with temperature?
In a closed system without loss, ordinary temperature changes mainly alter volume and density. The fuel mass remains approximately constant.
Can this replace ASTM or API correction tables?
No. The linear correction model is intended for estimation. Certified transactions and regulated operations may require standardized tables, calibrated equipment, and documented procedures.
Why is my density outside the preset range?
The selected fuel may have a different blend, temperature basis, contamination level, or specification. Check units, temperature, sample quality, and source documentation.
How is partial horizontal tank volume calculated?
The calculator uses the circular-segment area determined by liquid depth, then multiplies that area by tank length.
What expansion coefficient should I use?
Use a coefficient supplied for the actual product and temperature range. Presets are approximate and should be edited when verified data are available.
Accuracy and safety limitations
Always follow applicable fire, environmental, transport, workplace, aviation, marine, tax, and measurement regulations. Confirm tank ratings and leave required thermal-expansion space.