The pilot will perform a number of calculations during preflight planning and those we use on the site are listed below for convenient access. Sometimes the use of a special aviation calculator (E6B mechanical models or electronic Jeppesen and other apps) is required, other times it can be done without the use of such devices. Have a look at our E6B Tools above too!
Previous article discussed the formula's used in aviation calculations but sometimes we need to convert between different systems be that volumes, densities or mass. The table below shows some of the common ones used. For common fuel conversions hover your mouse over the image to the right/above. We also provide the most commonly used prefixes that are used with these base units.
Using these conversions is quite simple. For example: to convert 150 US gallon to liters is 150 x 3.785 = 567.75 liters. If you want to convert from liters to US gallon then divide the number of liters by the conversion factor.
| Volume, SI unit cubic meter (m3) | ||
| Convert from: | To: | Multiply by: |
| m3 | ft3 | 35.315 |
| in3 | cm3 | 16.387 |
| US Gal | liters | 3.785 |
| UK Gal (Imperial) | liters | 4.546 |
| US Gal | m3 | 3.785 x 10-3 |
| UK Gal (Imperial) | m3 | 4.546 x 10-3 |
| Mass (Weight), SI unit kilogram (kg) | ||
| Convert from: | To: | Multiply by: |
| kg | lb | 2.2046 |
| lb | g | 4.536 x 102 |
| Pressure, SI unit Newton/square meter (N/m2) | ||
| Convert from: | To: | Multiply by: |
| N/m2 (pa) | bar | 10-5 |
| lbf/in2 (psi) | N/m2 (pa) | 6.895 x 103 |
| lbf/in2 | hPa (mbar) | 68.948 |
| kgf/cm2 | N/m | 9.807 x 104 |
| inHg | hPa (mbar) | 33.864 |
| Bar | Pa (N/m2) | 105 |
| Energy / Power / Heat flow SI unit Watt (W) | ||
| Convert from: | To: | Multiply by: |
| hp | kW | 0.7457 (electric) |
| hp (metric) | kW | 0.7355 |
| ft.lbf/s | W | 1.3558 |
| Btu/hr | W | 0.2931 |
| kWh | MJ | 3.6 |
| cal | J | 4.1868 |
| Btu | kJ | 1.055 |
| Btu | kWh | 2.9307 x 10-4 |
Sometimes I see these prefixes not being used in the correct way. For example: the use of the kilo prefix is being mistakenly written as K (which is Kelvin) where it should be k (lower case). The table below shows them with their factor.
| Commonly used Metric prefixes with SI base units | ||
| Prefix | Symbol | Factor |
| Yotta | Y | 1024 |
| Zeta | Z | 1021 |
| Exa | E | 1018 |
| Peta | P | 1015 |
| Tera | T | 1012 |
| Giga | G | 109 |
| Mega | M | 106 |
| kilo | k | 103 |
| hecto | h | 102 |
| deca | da | 101 |
| deci | d | 10-1 |
| centi | c | 10-2 |
| milli | m | 10-3 |
| micro | μ | 10-6 |
| nano | n | 10-9 |
| pico | p | 10-12 |
| femto | f | 10-15 |
| atto | a | 10-18 |
| zepto | z | 10-21 |
| yocto | y | 10-24 |
More commonly used conversions can be found on websites like unitconverters.net, onlineconversion.com and wikipedia.
