Oil tank charts by size
Every chart converts a stick reading in inches to gallons of heating oil. If you are not sure which tank you have, start with what size is my oil tank, or measure yours and use the heating oil tank calculator.
Vertical and horizontal are not the same chart
A 275 vertical and a 275 horizontal hold the same oil, but the stick does not agree. A 13 inch wet line is 72 gallons on the vertical chart and 131 on the horizontal. Check which way the oval sits before you pick one.
Above ground steel tanks
The standard basement or outdoor tank is an oval (obround) steel tank. Vertical means the oval stands tall, horizontal means it lies on its side. Measure depth through the fill or gauge opening.
Underground (buried) tanks
Buried residential tanks are round steel cylinders read through the fill pipe. If your house predates the 1980s and has no visible tank, it is likely one of these. See how to stick a tank for the buried-tank procedure.
A buried stick reading does not name the tank
The buried steel cylinders are all 48 inches across and differ only in length, so the stick alone cannot separate them. A 30 inch wet line is 371 gallons on a 550, 670 on a 1000, and 335 on the less common 500. Before you order oil, settle it from installation records, or from one delivery and two stick readings in the buried tank size calculator. A tank that reads past 48 inches full is not a cylinder at all: the fiberglass balls read about 50, 62 and 76 inches full.
By brand
Print every chart at once
Pick your tank above and print its own sheet, or take one PDF with all 15 charts in it, a page each: the seven standard steel sizes, the three fiberglass balls, and the five Roth double wall models. Print the page that matches your tank and tape it inside the basement door. Every sheet carries a code that opens its own chart on your phone.
Full on the chart is not a full delivery
The steel tank charts here run all the way to the top of the tank. A delivery stops short of that, because the vent whistle goes quiet while an air gap is still at the top. A near-empty 275 usually takes a 230 to 250 gallon fill rather than the 274 gallons the chart shows at 44 inches.
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