🐠 Fish Tank Weight Calculator
Calculate the total weight of your aquarium — empty, full of water, and with substrate included
| Tank Name | Dimensions (L✕W✕H in) | Volume (gal / L) | Water Weight (fresh) | Est. Full Weight |
|---|---|---|---|---|
| Nano 5 Gallon | 12" ✕ 6" ✕ 8" | 5 gal / 19 L | 42 lbs / 19 kg | ~55 lbs / 25 kg |
| 10 Gallon Standard | 20" ✕ 10" ✕ 12" | 10 gal / 38 L | 83 lbs / 38 kg | ~111 lbs / 50 kg |
| 20 Gallon Long | 30" ✕ 12" ✕ 12" | 20 gal / 76 L | 167 lbs / 76 kg | ~200 lbs / 91 kg |
| 29 Gallon Standard | 30" ✕ 12" ✕ 18" | 29 gal / 110 L | 242 lbs / 110 kg | ~290 lbs / 132 kg |
| 40 Gallon Breeder | 36" ✕ 18" ✕ 16" | 40 gal / 151 L | 334 lbs / 151 kg | ~400 lbs / 182 kg |
| 55 Gallon Standard | 48" ✕ 13" ✕ 21" | 55 gal / 208 L | 459 lbs / 208 kg | ~530 lbs / 240 kg |
| 75 Gallon Standard | 48" ✕ 18" ✕ 21" | 75 gal / 284 L | 626 lbs / 284 kg | ~710 lbs / 322 kg |
| 90 Gallon Standard | 48" ✕ 18" ✕ 25" | 90 gal / 341 L | 751 lbs / 341 kg | ~850 lbs / 386 kg |
| 125 Gallon Standard | 72" ✕ 18" ✕ 22" | 125 gal / 473 L | 1,043 lbs / 473 kg | ~1,200 lbs / 544 kg |
| 180 Gallon Standard | 72" ✕ 24" ✕ 25" | 180 gal / 681 L | 1,502 lbs / 681 kg | ~1,700 lbs / 771 kg |
| Volume | Glass Tank (lbs/kg) | Acrylic Tank (lbs/kg) | Glass-to-Water Ratio |
|---|---|---|---|
| 5 gal | 7 lbs / 3.2 kg | 3 lbs / 1.4 kg | 1:6 |
| 10 gal | 11 lbs / 5 kg | 6 lbs / 2.7 kg | 1:7.5 |
| 20 gal | 25 lbs / 11.3 kg | 13 lbs / 5.9 kg | 1:6.7 |
| 29 gal | 32 lbs / 14.5 kg | 17 lbs / 7.7 kg | 1:7.6 |
| 40 gal | 55 lbs / 24.9 kg | 28 lbs / 12.7 kg | 1:6.1 |
| 55 gal | 78 lbs / 35.4 kg | 40 lbs / 18.1 kg | 1:5.9 |
| 75 gal | 140 lbs / 63.5 kg | 72 lbs / 32.7 kg | 1:4.5 |
| 125 gal | 206 lbs / 93.4 kg | 105 lbs / 47.6 kg | 1:5.1 |
| Substrate Type | Density (g/cm³) | lbs per gallon of tank volume per inch depth | kg per liter of tank volume per cm depth |
|---|---|---|---|
| Aquarium Gravel | 1.6–1.8 | ~0.92 lbs/gal/in | ~0.11 kg/L/cm |
| Pool Filter Sand | 1.7–1.9 | ~1.00 lbs/gal/in | ~0.12 kg/L/cm |
| Planted Soil (Aquasoil) | 0.9–1.1 | ~0.71 lbs/gal/in | ~0.085 kg/L/cm |
| Crushed Coral | 1.8–2.1 | ~1.13 lbs/gal/in | ~0.135 kg/L/cm |
| Live Rock (approx.) | 1.3–1.6 | ~0.80 lbs/gal/in | ~0.096 kg/L/cm |
Folks commonly underestimate the weight of a Fish Tank. The main reason is water. One gallon of fresh water weighs around 8,34 pounds while saltwater reaches about 8,55 pounds each gallon.
That tiny difference comes from the dissolved salt, that adds weight based on the salt level.
How Heavy Is a Fish Tank?
The glass itself is also heavy. An empty 55-gallon Fish Tank weighs around 100 pounds. For 75 gallons it reaches maybe 140 pounds.
A 90-gallon one sits more near 160 pounds before water goes in. Some occasionally mentioned heavy Fish Tank models from thick 10 mm glass, two strong folks had to carry it without water, and it passed 50 kilos.
So one must consider the soil, base, stones, filters, lamps, decorations and everything else, that builds it. Everything adds up quickly. In my experience, a good rough number is between 10 and 12 pounds each gallon, if one includes everything.
Like this a 50-gallon setup can easily reach 500 pounds total.
A full 20-gallon Fish Tank usually weighs around 225 pounds. A loaded 55-gallon one? It can have from 500 to 650 pounds.
For 75 gallons one could reach 850 pounds. A 125-gallon Fish Tank gets around 1 400 pounds, when it is fully filled with substrate and devices. Even a small 5-gallon setup weighs 50 to 60 pounds, after everthing is put together.
Here basic knowledge is important. Commonly home floors hold around 40 pounds each square foot. If you place the tank beside an outer wall or above a support wall, the wait goes directly down through the structure.
A stand with flat base spreads the load great, which beats those four-legged models, that focus everything in four little spots. Laying a sheet of plywood below also helps to spread the weight.
Apartments and upper floors need more attention. A big Fish Tank on the third floor? It is a risky idea.
Concrete floors handle heavy setups much better than raised wooden floors. Funny, in the 80s and 90s folks had 2 000-pound Fish Tank setups in bedrooms without problems, so floors can hold more than one thinks.
One last tip… Never move a full tank. Even a 10-gallon one gets really heavy, whenit is full.
Empty it first, always.
