330 gallon horizontal oil tank chart
The 330 gallon horizontal tank is the biggest of the common ovals, and the easiest one to read wrong: 44″ wide, 27″ tall, 72″ long. All 329 gallons fit under a stick scale that tops out at 27 inches, so one inch of depth covers a lot of oil. Read the wet line and convert below.
Type a reading, or drag the level ↕
| Inches | Gallons | Inches | Gallons |
|---|---|---|---|
| 1″ | 8 | 15″ | 185 |
| 2″ | 17 | 16″ | 199 |
| 3″ | 27 | 17″ | 213 |
| 4″ | 39 | 18″ | 227 |
| 5″ | 50 | 19″ | 240 |
| 6″ | 63 | 20″ | 253 |
| 7″ | 75 | 21″ | 266 |
| 8″ | 89 | 22″ | 278 |
| 9″ | 102 | 23″ | 290 |
| 10″ | 116 | 24″ | 301 |
| 11″ | 129 | 25″ | 312 |
| 12″ | 143 | 26″ | 321 |
| 13″ | 157 | 27″ | 329 |
| 14″ | 171 |
Tap any row to send that reading to the gauge above.
Generated 2026-09-20. Computed from nominal tank geometry at 231 cubic inches per gallon, with a 2.2 percent dished-head allowance calibrated to the manufacturer’s published capacity chart. Matches the chart books oil dealers use within about a gallon.
Preview the printable sheet
Reading the numbers
- Full is about 329 gallons, the same oil a 330 vertical holds, read on a 27 inch scale instead of 44.
- Half is 13.5 inches, 164 gallons. A quarter (about 82 gallons) sits at about 8 inches.
- The middle band runs about 14 gallons per inch, the steepest of the household ovals. Stood upright, the very same tank moves only about 8.6 gallons per inch.
- At 5 inches you are near 50 gallons. In the heating season, order a delivery that day.
- Confirm the length before trusting any oval chart. 72 inches end to end is a 330; 60 inches is a 275.
Common questions
Is my horizontal oval really a 330?
Every common horizontal oval lies 44 inches wide and 27 inches tall, so the end profile cannot tell you. Measure end to end: 72 inches is a 330, and anything a foot shorter is not. Then confirm against the data plate if it is legible.
What if I read this tank with a chart for a shorter oval?
About 20 percent low at any depth. At 15 inches the 275 gallon horizontal oil tank chart shows 154 gallons; this tank actually holds about 185 at the same reading.
How many gallons per inch?
About 14 at mid height, where the rounded ends are at their full spread. Nearer the top and the bottom the oil surface narrows and an inch is worth under 9. Use the chart for the conversion rather than multiplying, especially at the ends of the scale.
Is my 330 vertical or horizontal?
Stand at the oval end. Wider than tall means horizontal, and this chart applies. Taller than wide means you want the 330 vertical chart, where the same oil reads across 44 inches.
Related
- 330 gallon vertical chart (same tank stood on end)
- All tank charts by size
- How to stick an oil tank
- How long will my oil last?
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