Gross vs actual volume
20 × 10 × 12 in multiplies out to 10.4 US gallons, but that box includes the glass and runs to the very top of the frame. Taking off 4 mm of glass on each side and the base, and filling to 1 inch below the rim, leaves about 8.9 gallons of water. Gravel, rock and wood take that down further; the volume calculator estimates it for your aquascape.
How much a filled 10 gallon weighs
| Water | ≈ 66 lb |
| Glass | ≈ 13 lb |
| Gravel (2 in) | ≈ 22 lb |
| Total | ≈ 102 lb |
|---|
Water weighs 8.34 lb per US gallon, so it is most of the load. Put the tank on a stand rated for it, level, and supported under the whole frame. More on this in how much a fish tank weighs.
Heater and filter
Holding 78 °F in a 68 °F room with a lid takes about 50 W of heater, using the same heat-loss model as the heater calculator (compare sizes on the heater size comparison). For filtration, a common target is turning the water over 4–6 times an hour: 36–54 gallons per hour of rated flow.
Frequently asked questions
What are the dimensions of a 10 gallon tank?
A standard 10 gallon aquarium is 20 × 10 × 12 in (length × width × height), or about 51 × 25 × 30 cm. These are outside dimensions; brands differ by a fraction of an inch.
How many gallons does a 10 gallon tank actually hold?
Its outside dimensions work out to 10.4 US gallons (39 liters). Inside the glass, with the water about an inch below the rim, it holds roughly 9 gallons (34 liters), and less once gravel and rock go in.
How much does a 10 gallon aquarium weigh when full?
Roughly 102 lb (46 kg): about 66 lb of water, 13 lb of glass and 22 lb for a 2 inch gravel bed. Rock, decor and the stand add to that.
What size heater does a 10 gallon need?
About 50 W to hold 78 °F in a 68 °F room with a lid. A colder room or an open top needs more; the heater calculator works it out for your conditions.