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Oil and propane tank calculator

Read your tank, enter the reading, and see how many gallons are left. For heating oil that is a dip stick or float gauge in inches; for propane it is the percent on the gauge. Add a few dated readings and it also estimates when the tank runs low at the rate you have been using it.

Your tank

Preset sizes are outside dimensions and approximate. Measure your own tank if you can; height is the direction your dip stick goes. With a label capacity filled in, every row is scaled so a full tank equals it. The presets for double-wall and bunded tanks do this, because the inner tank is much smaller than the outside. Their walls are ribbed and uneven, so for them the % full reading is the useful part and the volume is rough.

Oil in the tank
119.9 gal
Full
44.8%
Tank holds 267.9 gal to the very top. Room for 148.0 gal more.

When will the oil run out?

Enter dated dip readings, in any order. Dip after the truck leaves, and add each delivery with its date and amount. The estimate uses the average from the first reading to the last.

DateDip (in)
Delivery dateAmount (gal)

The pipe to the burner draws from a little above the bottom, so a tank stops feeding before it reads zero. Set the level you treat as empty; it starts at 10%.

Add at least two dated dip readings. See an example.

Nothing is saved on this site. Your tank and readings live in the link, so bookmark it and add the next reading to it.

Chart for this tank

45 rows, 267.9 gal when full

DipOilFull
0 in 0.0 gal 0.0%
1 in 1.8 gal 0.7%
2 in 5.0 gal 1.9%
3 in 9.0 gal 3.4%
4 in 13.7 gal 5.1%
5 in 19.0 gal 7.1%
6 in 24.6 gal 9.2%
7 in 30.6 gal 11.4%
8 in 36.9 gal 13.8%
9 in 43.4 gal 16.2%
10 in 50.1 gal 18.7%
11 in 56.9 gal 21.2%
12 in 63.9 gal 23.8%
13 in 70.9 gal 26.4%
14 in 77.9 gal 29.1%
15 in 84.9 gal 31.7%
16 in 91.9 gal 34.3%
17 in 98.9 gal 36.9%
18 in 105.9 gal 39.5%
19 in 112.9 gal 42.1%
20 in 119.9 gal 44.8%
21 in 127.0 gal 47.4%
22 in 134.0 gal 50.0%
23 in 141.0 gal 52.6%
24 in 148.0 gal 55.2%
25 in 155.0 gal 57.9%
26 in 162.0 gal 60.5%
27 in 169.0 gal 63.1%
28 in 176.0 gal 65.7%
29 in 183.1 gal 68.3%
30 in 190.1 gal 70.9%
31 in 197.1 gal 73.6%
32 in 204.1 gal 76.2%
33 in 211.0 gal 78.8%
34 in 217.8 gal 81.3%
35 in 224.5 gal 83.8%
36 in 231.1 gal 86.2%
37 in 237.3 gal 88.6%
38 in 243.3 gal 90.8%
39 in 249.0 gal 92.9%
40 in 254.2 gal 94.9%
41 in 258.9 gal 96.6%
42 in 263.0 gal 98.1%
43 in 266.2 gal 99.3%
44 in 267.9 gal 100.0%

How the numbers are worked out

  • The volume at each depth comes from the shape of the tank's cross-section. An oval-ended tank is a rectangle with a half circle at each end, and the oil at a given depth fills part of that shape. Round tanks lying down use the same circle math. Upright round tanks and boxes fill evenly, so each inch holds the same amount.
  • The chart runs to the very top of the tank. Tanks are not filled that far: InspectAPedia notes a 275 gallon tank may be marked "Maximum Fill 247 gallons", leaving about 6 in of air at the top. PickHVAC puts the usual maximum fill for a 275 at 220 to 248 gal.
  • A 27 × 44 × 60 in tank works out to 267.9 gal by its shape, a little under the 275 on the label. My guess is that the outside size includes the steel and the rounded seams, and the label is a round number.
  • A tank that leans toward one end reads differently at each end. Dip at the middle of the tank if you can.
  • US gallons are 231 cubic inches. Liters are 1,000 cubic centimeters.

Where the preset sizes come from

Guides

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