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Aquarium Weight Calculator
A set-up aquarium weighs far more than its gallons suggest. A 55 gallon with 2 inches of sand comes to about 510 lb, a 75 gallon about 740 lb, and nearly all of it sits on a few square feet of floor. Pick your tank (or enter its size), add substrate, rock and the stand, and see the total, what it puts on the floor, and how to place it safely.
Aquarium weight calculator
Weight on the floor
- Empty tank
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- Water real volume
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- Substrate
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- Rock, decor and stand
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- Footprint
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- Load on the footprint
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- Versus a 40 lb/sq ft floor code minimum
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This is a planning estimate, not a structural check. Floors differ in span, joist size, age and condition. For a heavy tank, an upstairs room or any doubt, ask a structural engineer or a qualified builder before you fill it.
Equipment for this tank
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Next steps
- Tank sizes chart: compare footprints and stand sizes
- Substrate: how many bags of sand or gravel
- Heater size: watts for your room
How the weight is worked out
Most quick answers multiply the label gallons by 8.34 lb. That overstates the water, because glass, the gap below the rim and the substrate take up room, and it leaves out the tank, the sand and the rock. The calculator adds the parts up:
Sources. Standard tanks use the makers' own empty weights and exact sizes, as printed by Aqueon and Marineland (the same table as our tank sizes chart). For a custom tank the calculator estimates the bottom and four sides from their thickness, with float glass at 2,500 kg/m³ (Pilkington ATS-129) and acrylic at 1.19 g/cm³ (ISO 1183 datasheets); trim and braces add a little more. Fresh water uses 8.34 lb per US gallon, the figure used across this site. Seawater at 35 ppt and 25 °C is 1,023 kg/m³ against 997 kg/m³ for fresh water (TEOS-10), so a reef tank's water is 2.6% heavier. Substrate densities are the same as on our substrate calculator; they are estimates, because bags vary.
Can my floor hold it?
US homes are built to the International Residential Code, whose Table R301.5 sets a minimum design live load of 40 lb per sq ft for living areas and 30 lb per sq ft for sleeping areas. That figure is spread across the whole room. A tank concentrates its weight: a 55 gallon puts about 120 lb on each square foot it stands on, three times the design figure. Floors carry this every day because joists share the load, the rest of the room is lightly loaded, and codes build in safety margins. So the multiple is not a pass or fail; it shows how much placement matters.
- Under about 400 lb (up to about a 38 gallon, set up): a proper stand on any sound floor is normal.
- 400–1,000 lb (about 40 to 90 gallons): stand the tank across the floor joists rather than along one, close to a load-bearing wall, on a level floor.
- Over 1,000 lb (110 gallons and up): ask a structural engineer or builder first, especially upstairs or on an old or bouncy floor.
Those three bands are our own rule of thumb, not a code requirement; we could find no official limit for aquariums. The code figures come from IRC 2021 R301.5 (the 2024 edition keeps the same values); local codes can differ.
Example 1: Aqueon 55 gallon, freshwater, 2 in of sand
- Empty tank: Aqueon lists 78 lb for its 48¼ × 12¾ × 21 in tank.
- Water: with 5/16 in glass, the inside is 47⅝ × 12⅛ in, and the water stands 21 − 5/16 − 1 − 2 = 17 11/16 in deep: 10,214 in³ = 44.2 gal × 8.34 = 369 lb.
- Sand: 577.5 in² × 2 in = 0.67 ft³ × 100 = 67 lb.
- Total: 78 + 369 + 67 = 514 lb (233 kg) on 4.27 sq ft: 120 lb per sq ft, 3.0 times the code figure. Place with care.
Aqueon prints 625 lb "full" for this tank. That is more than even its whole outside volume of water plus the glass (about 544 lb), so treat it as a cautious upper figure. Your real number is lower, but a stand and rock bring it back up.
Example 2: custom acrylic reef tank
48 × 24 × 24 in, ½ in acrylic, saltwater, 2 in of live sand, 50 lb of rock and a 100 lb stand.
- Empty tank (estimate): panels of (48×24 + 2×48×24 + 2×24×24) × ½ = 2,304 in³ = 37.8 L × 1.19 kg/L = 44.9 kg = 99 lb.
- Water: 47 × 23 × 20.5 in = 95.9 gal × 8.34 × 1.026 = 821 lb.
- Live sand: 1,081 in² × 2 in = 1.25 ft³ × 120 = 150 lb. Plus 50 lb rock and the 100 lb stand.
- Total: 1,220 lb (554 kg) on 8 sq ft: 153 lb per sq ft, 3.8 times the code figure. Get advice before filling.
Example 3: 60 cm nano, in metric
60 × 30 × 36 cm, 6 mm glass, freshwater, 2.5 cm gap, 5 cm of gravel.
- Glass (estimate): (60×30 + 2×60×36 + 2×30×36) × 0.6 = 4,968 cm³ × 2.5 g = 12.4 kg.
- Water: 58.8 × 28.8 × 27.9 cm = 47.2 L, 47.2 kg.
- Gravel: 58.8 × 28.8 × 5 cm = 8.5 L, about 10.9 kg.
- Total: about 70.5 kg (155 lb) on 0.18 m², roughly 390 kg/m². Any sturdy stand will do.
Aquarium weight chart
Empty and "full" weights are as printed by each maker (– = that maker doesn't list the size). The set-up column is our estimate for freshwater with 2 in of sand and a 1 in gap, using Aqueon's tank where it lists one (Marineland's otherwise); add your stand and rock.
| Tank | Empty, lb Aqueon / Marineland | "Full" as printed, lb Aqueon / Marineland | Set up: water + 2 in sand our estimate | lb per sq ft on its footprint |
|---|---|---|---|---|
| 5½ gallon 16 × 8 × 10 in | 7 / 7 | 62 / 53 | 56 lb 25 kg | 60 |
| 10 gallon 20 × 10 × 12 in | 11 / 11 | 111 / 94 | 102 lb 46 kg | 69 |
| 15 gallon 24 × 12 × 12 in | 21 / 22 | 170 / 142 | 154 lb 70 kg | 73 |
| 20 gallon tall (high) 24 × 12 × 16 in | 25 / 27 | 225 / 187 | 200 lb 91 kg | 95 |
| 20 gallon long 30 × 12 × 12 in | 25 / 25 | 225 / 192 | 192 lb 87 kg | 73 |
| 29 gallon 30 × 12 × 18 in | 40 / 38 | 330 / 280 | 281 lb 127 kg | 107 |
| 30 gallon 36 × 12 × 16 in | 43 / 41 | 343 / 281 | 304 lb 138 kg | 96 |
| 33 gallon long 48 × 13 × 13 in | 46 / – | 382 / – | 328 lb 149 kg | 77 |
| 38 gallon 36 × 12 × 20 in | 47 / – | 427 / – | 355 lb 161 kg | 112 |
| 40 gallon breeder 36 × 18 × 16 in | 58 / 52 | 458 / 320 | 444 lb 201 kg | 97 |
| 40 gallon long 48 × 13 × 16 in | – / 52 | – / 386 | 412 lb 187 kg | 95 |
| 40 gallon high 36 × 13 × 20 in | – / 50 | – / 386 | 373 lb 169 kg | 118 |
| 45 gallon 36 × 12 × 24 in | 69 / – | 515 / – | 434 lb 197 kg | 137 |
| 50 gallon 36 × 18 × 19 in | 68 / – | 600 / – | 507 lb 230 kg | 109 |
| 55 gallon 48 × 13 × 21 in | 78 / 62 | 625 / 521 | 514 lb 233 kg | 120 |
| 60 gallon breeder 48 × 18 × 16 in | 43 / – | 543 / – | 534 lb 242 kg | 86 |
| 65 gallon 36 × 18 × 24 in | 90 / 87 | 775 / 607 | 660 lb 299 kg | 142 |
| 75 gallon 48 × 18 × 21 in | 98 / 89 | 785 / 715 | 739 lb 335 kg | 119 |
| 90 gallon 48 × 18 × 24 in | 135 / 125 | 1,050 / 876 | 880 lb 399 kg | 141 |
| 110 gallon 48 × 18 × 30 in | – / 204 | – / 1,125 | 1,117 lb 507 kg | 181 |
| 120 gallon 48 × 24 × 24 in | – / 175 | – / 1,177 | 1,163 lb 528 kg | 142 |
| 125 gallon 72 × 18 × 22 in | 177 / 160 | 1,400 / 1,160 | 1,208 lb 548 kg | 130 |
| 150 gallon 72 × 18 × 28 in | 281 / – | 1,800 / – | 1,600 lb 726 kg | 172 |
| 180 gallon 72 × 24 × 24 in | – / 348 | – / 1,788 | 1,746 lb 792 kg | 145 |
| 210 gallon 72 × 24 × 29 in | 343 / – | 2,450 / – | 2,122 lb 963 kg | 172 |
Makers' "full" figures differ for the same size because they count it differently: Marineland's are usually label gallons × 8.34 + the empty tank (not for every size), while Aqueon's are usually 8–15% above the tank's outside volume filled with water. Neither includes substrate or rock.
FAQ
How much does a 55 gallon fish tank weigh?
About 78 lb empty (Aqueon; Marineland lists 62 lb). Set up with water and 2 inches of sand, about 514 lb. Aqueon prints 625 lb and Marineland 521 lb as "full" weights. Add the stand and any rock.
How much does a 75 gallon fish tank weigh?
About 98 lb empty (Aqueon; Marineland 89 lb) and about 740 lb set up with water and 2 inches of sand. The makers print 785 lb (Aqueon) and 715 lb (Marineland) full.
How much does a 10 gallon fish tank weigh?
About 11 lb empty and roughly 100 lb set up with water and sand. Aqueon prints 111 lb full, Marineland 94 lb.
How much does a 20 gallon fish tank weigh?
A 20 long is about 25 lb empty and 190 lb set up; Aqueon prints 225 lb full. A 20 tall weighs about the same, but on a smaller footprint.
How much does a gallon of water weigh?
About 8.34 lb per US gallon of fresh water (1 kg per litre). Seawater is about 2.6% heavier, roughly 8.56 lb per gallon.
Is a saltwater tank heavier?
Yes, a little: seawater is about 2.6% heavier than fresh water, and reef tanks usually carry more rock and live sand. A 75 gallon reef with 80 lb of live rock and live sand comes to roughly 110 lb more than the same tank set up as a freshwater tank.
Can my floor hold a fish tank?
Most tanks under about 400 lb set up (up to roughly 38 gallons) are fine on any sound floor with a proper stand. From 400 to 1,000 lb, stand the tank across the floor joists, close to a load-bearing wall. Over 1,000 lb (110 gallons and up), ask a structural engineer or builder first. These bands are our rule of thumb, not a code limit.