Gallons at each gauge reading
Approximate gallons of oil in the tank. Cost to fill uses this week's U.S. average of $6.23 a gallon, before tax.
| Gauge | 275 upright | 275 flat | 330 upright | 330 flat | 500 round | 1000 round |
|---|---|---|---|---|---|---|
| 1/8 | 22 | 26 | 27 | 32 | 36 | 72 |
| 1/4 | 58 | 60 | 70 | 73 | 98 | 196 |
| 3/8 | 98 | 98 | 117 | 118 | 171 | 343 |
| 1/2 | 138 | 138 | 165 | 165 | 250 | 500 |
| 5/8 | 177 | 177 | 213 | 212 | 329 | 657 |
| 3/4 | 217 | 215 | 260 | 257 | 402 | 804 |
| 7/8 | 253 | 249 | 303 | 298 | 464 | 928 |
| Full | 275 | 275 | 330 | 330 | 500 | 1000 |
Cost to fill a 275-gallon tank
The most common home oil tank, standing upright, at this week's U.S. average. Dealers fill to about 248 gallons.
Gauge at 1/8
$1,404
about 225 gallons to fill
Gauge at 1/4
$1,178
about 189 gallons to fill
Gauge at 3/8
$932
about 150 gallons to fill
Gauge at 1/2
$686
about 110 gallons to fill
Gauge at 5/8
$439
about 70 gallons to fill
Gauge at 3/4
$193
about 31 gallons to fill
For your own state's price, use the tool at the top of this page or see heating oil prices by state.
Dipstick charts (inches to gallons)
Lower a clean stick to the bottom of the tank through the fill pipe, then read how many inches are wet.
275-gallon oval tank, standing upright — 44 inches tall
1″ 2 gal2″ 5 gal3″ 9 gal4″ 14 gal5″ 19 gal6″ 25 gal7″ 31 gal8″ 38 gal9″ 45 gal10″ 51 gal11″ 58 gal12″ 66 gal13″ 73 gal14″ 80 gal15″ 87 gal16″ 94 gal17″ 102 gal18″ 109 gal19″ 116 gal20″ 123 gal21″ 130 gal22″ 138 gal23″ 145 gal24″ 152 gal25″ 159 gal26″ 166 gal27″ 173 gal28″ 181 gal29″ 188 gal30″ 195 gal31″ 202 gal32″ 209 gal33″ 217 gal34″ 224 gal35″ 230 gal36″ 237 gal37″ 244 gal38″ 250 gal39″ 256 gal40″ 261 gal41″ 266 gal42″ 270 gal43″ 273 gal44″ 275 gal
275-gallon oval tank, lying flat — 27 inches tall
1″ 6 gal2″ 14 gal3″ 23 gal4″ 32 gal5″ 42 gal6″ 52 gal7″ 63 gal8″ 74 gal9″ 85 gal10″ 97 gal11″ 108 gal12″ 120 gal13″ 132 gal14″ 143 gal15″ 155 gal16″ 167 gal17″ 178 gal18″ 190 gal19″ 201 gal20″ 212 gal21″ 223 gal22″ 233 gal23″ 243 gal24″ 252 gal25″ 261 gal26″ 269 gal27″ 275 gal
330-gallon oval tank, standing upright — 44 inches tall
1″ 2 gal2″ 6 gal3″ 11 gal4″ 17 gal5″ 23 gal6″ 30 gal7″ 38 gal8″ 45 gal9″ 53 gal10″ 62 gal11″ 70 gal12″ 79 gal13″ 87 gal14″ 96 gal15″ 105 gal16″ 113 gal17″ 122 gal18″ 130 gal19″ 139 gal20″ 148 gal21″ 156 gal22″ 165 gal23″ 174 gal24″ 182 gal25″ 191 gal26″ 200 gal27″ 208 gal28″ 217 gal29″ 225 gal30″ 234 gal31″ 243 gal32″ 251 gal33″ 260 gal34″ 268 gal35″ 277 gal36″ 285 gal37″ 292 gal38″ 300 gal39″ 307 gal40″ 313 gal41″ 319 gal42″ 324 gal43″ 328 gal44″ 330 gal
330-gallon oval tank, lying flat — 27 inches tall
1″ 8 gal2″ 17 gal3″ 27 gal4″ 39 gal5″ 51 gal6″ 63 gal7″ 76 gal8″ 89 gal9″ 102 gal10″ 116 gal11″ 130 gal12″ 144 gal13″ 158 gal14″ 172 gal15″ 186 gal16″ 200 gal17″ 214 gal18″ 228 gal19″ 241 gal20″ 254 gal21″ 267 gal22″ 279 gal23″ 291 gal24″ 303 gal25″ 313 gal26″ 322 gal27″ 330 gal
500-gallon round tank (48-inch diameter) — 48 inches tall
1″ 3 gal2″ 7 gal3″ 13 gal4″ 20 gal5″ 28 gal6″ 36 gal7″ 45 gal8″ 55 gal9″ 65 gal10″ 75 gal11″ 86 gal12″ 98 gal13″ 109 gal14″ 121 gal15″ 133 gal16″ 146 gal17″ 158 gal18″ 171 gal19″ 184 gal20″ 197 gal21″ 210 gal22″ 224 gal23″ 237 gal24″ 250 gal25″ 263 gal26″ 276 gal27″ 290 gal28″ 303 gal29″ 316 gal30″ 329 gal31″ 342 gal32″ 354 gal33″ 367 gal34″ 379 gal35″ 391 gal36″ 402 gal37″ 414 gal38″ 425 gal39″ 435 gal40″ 445 gal41″ 455 gal42″ 464 gal43″ 472 gal44″ 480 gal45″ 487 gal46″ 493 gal47″ 497 gal48″ 500 gal
1,000-gallon round tank (64-inch diameter) — 64 inches tall
1″ 3 gal2″ 9 gal3″ 17 gal4″ 26 gal5″ 36 gal6″ 47 gal7″ 59 gal8″ 72 gal9″ 86 gal10″ 100 gal11″ 115 gal12″ 130 gal13″ 146 gal14″ 162 gal15″ 178 gal16″ 196 gal17″ 213 gal18″ 231 gal19″ 249 gal20″ 267 gal21″ 286 gal22″ 304 gal23″ 323 gal24″ 343 gal25″ 362 gal26″ 381 gal27″ 401 gal28″ 421 gal29″ 440 gal30″ 460 gal31″ 480 gal32″ 500 gal33″ 520 gal34″ 540 gal35″ 560 gal36″ 579 gal37″ 599 gal38″ 619 gal39″ 638 gal40″ 657 gal41″ 677 gal42″ 696 gal43″ 714 gal44″ 733 gal45″ 751 gal46″ 769 gal47″ 787 gal48″ 804 gal49″ 822 gal50″ 838 gal51″ 854 gal52″ 870 gal53″ 885 gal54″ 900 gal55″ 914 gal56″ 928 gal57″ 941 gal58″ 953 gal59″ 964 gal60″ 974 gal61″ 983 gal62″ 991 gal63″ 997 gal64″ 1000 gal
Which tank do I have?
- 275-gallon oval — the most common indoor tank: about 27 inches thick, 44 inches tall and 5 feet long. It usually stands upright on legs in a basement or garage.
- 330-gallon oval — the same shape but about 6 feet long.
- Round (cylinder) tanks — often 500 or 1,000 gallons, usually outdoors or buried. Check the label or your delivery tickets for the size.
Why the gauge isn't the same as gallons
The gauge is a float that shows how far up the tank the oil reaches. Oval and round tanks are narrower at the top and bottom, so the first and last few inches hold less oil than the middle. In an upright 275-gallon tank, a gauge reading of 1/4 means about 58 gallons — not 69.
When to order
Most dealers suggest ordering when the gauge reaches 1/4. That leaves a few days' margin in cold weather and avoids drawing sludge from the bottom of the tank into the burner. See how long your oil will last to plan your next delivery.
ℹ️ Figures are estimates from standard tank dimensions. Tanks that are tilted, dented or a different make can read differently. A smart tank monitor can track your level for you and warn you before you run low.