1000 gallon underground oil tank chart

The 1000 gallon underground tank serves larger properties and two-family homes: the same 48 inch diameter as a 550, stretched to about 130 inches long. The stick scale is identical, the gallons are not. Each wet inch here carries nearly twice the oil, so knowing which tank you own matters more than anywhere else on this site.

Enter a reading to convert it, fill the tank pictures, and highlight your row in the chart below.

empty
48″ across × 130″ long, buried
1000 gallon underground oil tank conversion chart, inches of oil to gallons
Inches Gallons Inches Gallons
1″ 5 25″ 536
2″ 15 26″ 563
3″ 27 27″ 590
4″ 41 28″ 617
5″ 56 29″ 643
6″ 73 30″ 670
7″ 92 31″ 696
8″ 112 32″ 721
9″ 132 33″ 746
10″ 154 34″ 771
11″ 176 35″ 796
12″ 199 36″ 819
13″ 223 37″ 842
14″ 247 38″ 865
15″ 272 39″ 886
16″ 297 40″ 907
17″ 323 41″ 926
18″ 349 42″ 945
19″ 375 43″ 962
20″ 402 44″ 978
21″ 428 45″ 992
22″ 455 46″ 1004
23″ 482 47″ 1013
24″ 509 48″ 1018

Generated 2026-06-12. Computed from nominal tank geometry at 231 cubic inches per gallon. Actual tanks vary by manufacturer; cross-check your tank data plate.

Reading the numbers

Common questions

How can I tell a 1000 from a 550?

Not with the stick: both tanks are 48 inches deep, and the length difference (about 130 inches against 72) is buried. Look for installation records or the original permit, or ask your oil company. One hard clue from delivery history: a single delivery larger than about 560 gallons cannot fit in a 550. What size is my oil tank has more.

Who actually has a 1000 gallon tank?

Larger single homes, two-family houses, and properties that were converted from small commercial use. The draw of the size is fewer deliveries: one tank can carry a long stretch of the heating season between fills.

How many gallons per inch?

About 27 through the middle band, far less in the first and last few inches where the round shell curves away. Always convert with the chart; straight multiplication on a cylinder goes wrong fast near the top and bottom.

Is the reading procedure different from a smaller buried tank?

No, it is the same fill-pipe technique: a 6 to 8 foot clean wooden stick, lowered gently to the bottom, wet line only, cap back on firmly. See the buried-tank section of how to stick an oil tank, including the water-finding paste check.

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