Sherafy Petroleum Institute

The tools and calculators listed on this page are for reference only. Please do your due diligence and verify these numbers within the proper published tables by API/ASTM/Etc. These tools are meant for convenience; specifically, my convenience, but I am making them available to you. These tools should not be used for determining the final outturn of a cargo transfer without proper verification on your end.

I have used baseline standards applicable to the petroleum industry in my calculations, so please keep this in mind. Each industry may use slightly different, though mostly trivial, baseline standards. Looking for unit and measurement conversions? Find them here!

Use the following calculator to interpolate volume from an observed sounding or ullage measurement. To use this calculator, you will need the calibration table of the tank or container you are measuring.

Example Calibration Table


You measure a sounding value of 112.4 Cm with a trim of 1.7M, you will enter the following:

Measured Gauge: 112.4

Trim: 1.7

Lower Volume Gauge: 112.0
You enter 112.0 because 112.0 is the lower listed boundary for your observed measurement of 112.4. Think of the upper and lower boundaries as two pieces of bread sandwiching your measured value.

High Volume Gauge: 114.00
Again, you enter 114.0 because this is the listed upper boundary for your measured value of 112.4 as seen on the table.

HVHT: 123.7
LVHT: 121.6
HVLT: 125.4
LVLT: 123.3
These values indicate four numbers as a quadrant on the calibration table. They are important because they define the parameters for interpolating the final observed volume.

Since our trim is 1.7M, we will be looking at the values that fall into the upper and lower bounds of the trim as well; in this case, it is 2M and 1M.

If you followed along correctly, the entered values should result in an interpolated volume of 122.530.

Almost everything will be the same for ullages, except the low and high volume gauges will be switched since a higher ullage value corresponds to a lower volume value.