Butane and Propane Conversion Chart: Pounds, Gallons and Liters
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Liquid solvent conversions for filling tanks, sizing recovery and checking inventory, at 60°F (16°C) and chilled.
DocumentREF-SC-01
SeriesEngineering Reference
Revision2026.1
Issued24 September 2026
Liquid density changes with temperature, so a pound of cold solvent takes up less room than a pound of warm solvent. Use the 60°F (16°C) tables for inventory and the density table for chilled solvent.
Quick conversions at 60°F (16°C)
| Solvent | lb per gal | gal per lb | in³ per lb | L per lb | lb per L | kg per L |
|---|---|---|---|---|---|---|
| n-Butane | 4.869 | 0.2054 | 47.4 | 0.777 | 1.286 | 0.583 |
| Propane | 4.221 | 0.2369 | 54.7 | 0.897 | 1.115 | 0.506 |
| 75/25 butane/propane | 4.707 | 0.2124 | 49.1 | 0.804 | 1.243 | 0.564 |
| 50/50 butane/propane | 4.545 | 0.2200 | 50.8 | 0.833 | 1.201 | 0.545 |
Blends are butane / propane by liquid volume: blend density = butane fraction x butane density + propane fraction x propane density.
Pounds to volume at 60°F (16°C)
| Solvent (lb) | Butane gal | Butane in³ | Butane L | Propane gal | Propane in³ | Propane L |
|---|---|---|---|---|---|---|
| 1 | 0.21 | 47 | 0.8 | 0.24 | 55 | 0.9 |
| 5 | 1.03 | 237 | 3.9 | 1.18 | 274 | 4.5 |
| 10 | 2.05 | 474 | 7.8 | 2.37 | 547 | 9.0 |
| 20 | 4.11 | 949 | 15.5 | 4.74 | 1,095 | 17.9 |
| 25 | 5.13 | 1,186 | 19.4 | 5.92 | 1,368 | 22.4 |
| 40 | 8.22 | 1,898 | 31.1 | 9.48 | 2,189 | 35.9 |
| 50 | 10.27 | 2,372 | 38.9 | 11.85 | 2,736 | 44.8 |
| 75 | 15.40 | 3,558 | 58.3 | 17.77 | 4,105 | 67.3 |
| 100 | 20.54 | 4,744 | 77.7 | 23.69 | 5,473 | 89.7 |
| 150 | 30.81 | 7,116 | 116.6 | 35.54 | 8,209 | 134.5 |
| 200 | 41.08 | 9,488 | 155.5 | 47.38 | 10,946 | 179.4 |
Liquid density vs temperature
| Temperature | Butane lb/gal | Butane kg/L | Propane lb/gal | Propane kg/L |
|---|---|---|---|---|
| -80°F (-62°C) | 5.54 | 0.663 | 5.03 | 0.603 |
| -60°F (-51°C) | 5.45 | 0.653 | 4.93 | 0.591 |
| -40°F (-40°C) | 5.35 | 0.642 | 4.82 | 0.578 |
| -20°F (-29°C) | 5.26 | 0.631 | 4.72 | 0.565 |
| 0°F (-18°C) | 5.17 | 0.619 | 4.60 | 0.551 |
| 20°F (-7°C) | 5.07 | 0.608 | 4.48 | 0.537 |
| 40°F (4°C) | 4.97 | 0.596 | 4.36 | 0.522 |
| 60°F (16°C) | 4.87 | 0.583 | 4.22 | 0.506 |
| 80°F (27°C) | 4.76 | 0.571 | 4.08 | 0.489 |
| 100°F (38°C) | 4.65 | 0.557 | 3.93 | 0.471 |
Fill cold tanks to no more than 75 percent. Butane at -40°F (-40°C) is about 10 percent denser than at 60°F (16°C); propane about 14 percent. A tank filled with chilled solvent to 90 percent can go liquid full as it warms to room temperature.
Formulas
| To get | Formula |
|---|---|
| Gallons | lb ÷ lb/gal |
| Cubic inches | gal x 231 |
| Liters | gal x 3.785 |
| Pounds in a tank | tank gal x fill fraction x lb/gal |
- Isobutane is lighter than n-butane, about 4.69 lb/gal at 60°F (16°C). Use n-butane values only for n-butane.
- Commercial blends vary by supplier. For certified purity solvent, use the density on the supplier's certificate of analysis when it is given.
Sources. Saturated liquid density of n-butane and propane from NIST-based tables published by The Engineering ToolBox, interpolated to the temperatures shown. 60°F values agree with GPSA specific gravities within 0.2 percent.
Questions about your system? Call the shop at 541-330-6409, Monday to Thursday, 8 to 4 Pacific, or email info@nboler.com.