275 gallon oil tank chart
The common 275 gallon heating oil tank is a steel box with rounded ends, about 27 in wide, 44 in tall and 60 in long (outside sizes from InspectAPedia's tank size table; yours may differ by an inch or so). It can stand on its legs with the 44 in side up, or lie on its side with the 27 in side up. The same dip reading means a different amount of oil in each position, so there are two tables below.
Half full is 22 in on a standing tank and 13.5 in on one lying down (134.0 gal either way).
Which way is your tank?
Measure from the floor of the tank to the top. About 44 in means it stands up (called vertical): the rounded ends are at the top and bottom. About 27 in means it lies down (horizontal): the rounded ends are the sides. A 330 gallon tank has the same end shape and is 72 in long; it is a preset in the calculator. If your tank measures something else, enter its size in the calculator and it makes a chart for it.
Standing up (vertical), 44 in tall
Near the bottom and the top, each inch holds less because the ends are rounded. Between about 14 and 30 in every inch holds the same 7.0 gal.
| Dip | Gallons | Full |
|---|---|---|
| 0 in | 0.0 | 0.0% |
| 1 in | 1.8 | 0.7% |
| 2 in | 5.0 | 1.9% |
| 3 in | 9.0 | 3.4% |
| 4 in | 13.7 | 5.1% |
| 5 in | 19.0 | 7.1% |
| 6 in | 24.6 | 9.2% |
| 7 in | 30.6 | 11.4% |
| 8 in | 36.9 | 13.8% |
| 9 in | 43.4 | 16.2% |
| 10 in | 50.1 | 18.7% |
| 11 in | 56.9 | 21.2% |
| 12 in | 63.9 | 23.8% |
| 13 in | 70.9 | 26.4% |
| 14 in | 77.9 | 29.1% |
| 15 in | 84.9 | 31.7% |
| 16 in | 91.9 | 34.3% |
| 17 in | 98.9 | 36.9% |
| 18 in | 105.9 | 39.5% |
| 19 in | 112.9 | 42.1% |
| 20 in | 119.9 | 44.8% |
| 21 in | 127.0 | 47.4% |
| 22 in | 134.0 | 50.0% |
| 23 in | 141.0 | 52.6% |
| 24 in | 148.0 | 55.2% |
| 25 in | 155.0 | 57.9% |
| 26 in | 162.0 | 60.5% |
| 27 in | 169.0 | 63.1% |
| 28 in | 176.0 | 65.7% |
| 29 in | 183.1 | 68.3% |
| 30 in | 190.1 | 70.9% |
| 31 in | 197.1 | 73.6% |
| 32 in | 204.1 | 76.2% |
| 33 in | 211.0 | 78.8% |
| 34 in | 217.8 | 81.3% |
| 35 in | 224.5 | 83.8% |
| 36 in | 231.1 | 86.2% |
| 37 in | 237.3 | 88.6% |
| 38 in | 243.3 | 90.8% |
| 39 in | 249.0 | 92.9% |
| 40 in | 254.2 | 94.9% |
| 41 in | 258.9 | 96.6% |
| 42 in | 263.0 | 98.1% |
| 43 in | 266.2 | 99.3% |
| 44 in | 267.9 | 100.0% |
Lying down (horizontal), 27 in tall
Each inch holds more here, up to 11.4 gal at the middle, because the tank is wide and low.
| Dip | Gallons | Full |
|---|---|---|
| 0 in | 0.0 | 0.0% |
| 1 in | 6.2 | 2.3% |
| 2 in | 13.8 | 5.2% |
| 3 in | 22.3 | 8.3% |
| 4 in | 31.4 | 11.7% |
| 5 in | 41.0 | 15.3% |
| 6 in | 51.1 | 19.1% |
| 7 in | 61.5 | 23.0% |
| 8 in | 72.2 | 26.9% |
| 9 in | 83.1 | 31.0% |
| 10 in | 94.2 | 35.2% |
| 11 in | 105.5 | 39.4% |
| 12 in | 116.8 | 43.6% |
| 13 in | 128.3 | 47.9% |
| 14 in | 139.7 | 52.1% |
| 15 in | 151.1 | 56.4% |
| 16 in | 162.4 | 60.6% |
| 17 in | 173.7 | 64.8% |
| 18 in | 184.8 | 69.0% |
| 19 in | 195.7 | 73.1% |
| 20 in | 206.4 | 77.0% |
| 21 in | 216.8 | 80.9% |
| 22 in | 226.9 | 84.7% |
| 23 in | 236.5 | 88.3% |
| 24 in | 245.7 | 91.7% |
| 25 in | 254.1 | 94.8% |
| 26 in | 261.7 | 97.7% |
| 27 in | 267.9 | 100.0% |
Why a full tank shows 267.9 gal
These tables come from the shape: a 27 × 44 in rounded rectangle, 60 in long, filled to the very top. Worked out from those outside measurements, the tank holds 267.9 gal, about 2.6% under the 275 on the label. My guess is that the outside size includes the steel and the rounded seams, and that 275 is a rounded label figure. If you know your tank's exact inside size, enter it in the calculator.
A tank is never filled to the top. InspectAPedia notes that a 275 gallon tank may be marked "Maximum Fill 247 gallons", which leaves about 6 in of air space, and PickHVAC gives 220 to 248 gal as the usual maximum fill. So a delivery tops out well below the last rows of these tables. What that costs at today's prices is on the cost to fill a tank page.
How to dip an oil tank
- Use a clean wooden stick or a dip stick marked in inches, longer than the tank is tall.
- Open the fill cap or the gauge port on top. Lower the stick straight down until it touches the bottom, then pull it out.
- Read where the wet line ends. Oil soaks into bare wood, so the line is easier to see on a plain stick.
- Look the reading up in the table for your tank, or type it into the gauge.
- Close the cap tightly so rain cannot get in.
The float gauge on top of most tanks shows quarters (F, ¾, ½, ¼). A quarter of this tank is 67 gal: about 12 in on the stick when it stands up and 8 in when it lies down. Float gauges are rough, so a dip now and then is worth it.
Knowing when to order
Two readings a week or two apart tell you how much you burn per day. The run-out guide walks through the math, and the calculator does it for your own readings. For a rough idea of how many days a full tank lasts at different temperatures, see how long a 275 gallon tank lasts.