330 gallon oil tank chart
A 330 gallon tank is the 275 with 12 in more length: about 27 in wide, 44 in tall and 72 in long (PickHVAC and InspectAPedia list the same sizes; yours may differ by an inch). It stands on legs with the 44 in side up, or lies on its side with the 27 in side up. Below are inch tables for both, then what the float gauge marks mean in gallons.
That is about 2.6% under the 330 on the label, because the outside size includes the steel. The same 22 in dip is 160.8 gal here and 134.0 gal in a 275, so the two charts are not interchangeable.
Float gauge marks in gallons
The gauge on top shows F, ¾, ½, ¼. Float gauges are rough, but the marks are quick to read. This table gives the gallons at each mark and the dip stick reading that matches it (to the nearest half inch), so you can check one against the other.
| Gauge | Gallons | Dip, standing | Dip, lying |
|---|---|---|---|
| Full | 322 | 44.0 in | 27.0 in |
| 3/4 | 241 | 31.5 in | 19.5 in |
| 1/2 | 161 | 22.0 in | 13.5 in |
| 1/4 | 80 | 12.5 in | 7.5 in |
| 1/8 | 40 | 7.5 in | 4.0 in |
A gauge at ¼ means roughly 80 gal left, which is about 20 days at an example burn of 4 gal a day (yours will differ). Plan the call before it gets there.
Standing up (vertical), 44 in tall
Through the straight middle section every inch holds 8.4 gal. That is 1.4 gal more per inch than the 275, with the same height.
| Dip | Gallons | Full |
|---|---|---|
| 0 in | 0.0 | 0.0% |
| 1 in | 2.1 | 0.7% |
| 2 in | 6.0 | 1.9% |
| 3 in | 10.8 | 3.4% |
| 4 in | 16.5 | 5.1% |
| 5 in | 22.8 | 7.1% |
| 6 in | 29.5 | 9.2% |
| 7 in | 36.7 | 11.4% |
| 8 in | 44.3 | 13.8% |
| 9 in | 52.1 | 16.2% |
| 10 in | 60.1 | 18.7% |
| 11 in | 68.3 | 21.2% |
| 12 in | 76.6 | 23.8% |
| 13 in | 85.0 | 26.4% |
| 14 in | 93.4 | 29.1% |
| 15 in | 101.9 | 31.7% |
| 16 in | 110.3 | 34.3% |
| 17 in | 118.7 | 36.9% |
| 18 in | 127.1 | 39.5% |
| 19 in | 135.5 | 42.1% |
| 20 in | 143.9 | 44.8% |
| 21 in | 152.3 | 47.4% |
| 22 in | 160.8 | 50.0% |
| 23 in | 169.2 | 52.6% |
| 24 in | 177.6 | 55.2% |
| 25 in | 186.0 | 57.9% |
| 26 in | 194.4 | 60.5% |
| 27 in | 202.8 | 63.1% |
| 28 in | 211.3 | 65.7% |
| 29 in | 219.7 | 68.3% |
| 30 in | 228.1 | 70.9% |
| 31 in | 236.5 | 73.6% |
| 32 in | 244.9 | 76.2% |
| 33 in | 253.2 | 78.8% |
| 34 in | 261.4 | 81.3% |
| 35 in | 269.5 | 83.8% |
| 36 in | 277.3 | 86.2% |
| 37 in | 284.8 | 88.6% |
| 38 in | 292.0 | 90.8% |
| 39 in | 298.8 | 92.9% |
| 40 in | 305.0 | 94.9% |
| 41 in | 310.7 | 96.6% |
| 42 in | 315.6 | 98.1% |
| 43 in | 319.4 | 99.3% |
| 44 in | 321.5 | 100.0% |
Lying down (horizontal), 27 in tall
A lying tank is shallow, so a one inch error in the dip is worth up to 13.7 gal. Wipe the stick and dip twice.
| Dip | Gallons | Full |
|---|---|---|
| 0 in | 0.0 | 0.0% |
| 1 in | 7.4 | 2.3% |
| 2 in | 16.6 | 5.2% |
| 3 in | 26.7 | 8.3% |
| 4 in | 37.7 | 11.7% |
| 5 in | 49.2 | 15.3% |
| 6 in | 61.3 | 19.1% |
| 7 in | 73.8 | 23.0% |
| 8 in | 86.6 | 26.9% |
| 9 in | 99.8 | 31.0% |
| 10 in | 113.1 | 35.2% |
| 11 in | 126.6 | 39.4% |
| 12 in | 140.2 | 43.6% |
| 13 in | 153.9 | 47.9% |
| 14 in | 167.6 | 52.1% |
| 15 in | 181.3 | 56.4% |
| 16 in | 194.9 | 60.6% |
| 17 in | 208.4 | 64.8% |
| 18 in | 221.8 | 69.0% |
| 19 in | 234.9 | 73.1% |
| 20 in | 247.7 | 77.0% |
| 21 in | 260.2 | 80.9% |
| 22 in | 272.3 | 84.7% |
| 23 in | 283.8 | 88.3% |
| 24 in | 294.8 | 91.7% |
| 25 in | 305.0 | 94.8% |
| 26 in | 314.1 | 97.7% |
| 27 in | 321.5 | 100.0% |
Worked example: when to call
A standing 330 tank dips 15 in. The table gives 101.9 gal (32% full). Keep a reserve of 10% of the tank (32 gal) so the tank never runs close to empty. That leaves 70 gal to burn. At 4 gal a day, that lasts 17 days, so the call goes in about a week before then, since deliveries can take a few days in a cold spell.
Your own burn rate comes from two dips a week or two apart. The run-out guide shows the steps, and the calculator with a 330 preset does it for you.
What a delivery can add
Tanks are not filled to the brim: a 275 is often marked for a maximum fill of 247 gal (about 90%). At the same 90%, a 330 takes roughly 289 gal at most. From the 102 gal above, that is a delivery of about 187 gal. For dollars at your price, see the cost to fill a tank. Not sure how your tank sits? The 275 gallon chart explains how to tell standing from lying.