Aquarium Tank Weight Calculator
Calculate the total weight of your filled aquarium. Water weighs 8.34 lbs per gallon - a filled tank is much heavier than most people expect!
Enter Tank Details
Enter your aquarium's capacity in US gallons
Total Weight
Enter tank size to calculate weight
Common Aquarium Weights (Filled)
| Tank Size | Water Weight | Total (Glass) | Notes |
|---|---|---|---|
| 5 gallons | 42 lbs | ~62 lbs | Desk/shelf safe |
| 10 gallons | 83 lbs | ~111 lbs | Sturdy furniture needed |
| 20 gallons | 167 lbs | ~225 lbs | Dedicated stand recommended |
| 29 gallons | 242 lbs | ~330 lbs | Floor placement preferred |
| 40 gallons | 334 lbs | ~455 lbs | Check floor support |
| 55 gallons | 459 lbs | ~625 lbs | Ground floor/reinforced |
| 75 gallons | 626 lbs | ~850 lbs | Structural consideration |
| 90 gallons | 751 lbs | ~1050 lbs | Professional assessment |
| 125 gallons | 1043 lbs | ~1400 lbs | Concrete/reinforced floor |
| 180 gallons | 1501 lbs | ~2000 lbs | Engineering consultation |
*Total includes estimated tank, substrate (~2"), and basic stand. Actual weight varies by manufacturer.
Floor Support Guidelines
✓ Generally Safe
- • Tanks under 20 gallons on sturdy furniture
- • Ground floor concrete slab placement
- • Load-bearing walls as backing
- • Tank perpendicular to floor joists
- • Modern construction (post-1970s)
⚠️ Requires Assessment
- • Tanks over 55 gallons on upper floors
- • Older homes with original flooring
- • Placement far from load-bearing walls
- • Multiple heavy items in same area
- • Signs of floor sagging or bounce
Tip: Position tanks perpendicular to floor joists to distribute weight across multiple joists. When in doubt, consult a structural engineer or your landlord.
Frequently Asked Questions
How much does water weigh?
Fresh water weighs 8.34 pounds per gallon (US). Saltwater is slightly heavier at about 8.56 lbs/gallon due to dissolved salt.
Why is my tank heavier than calculated?
Rocks, driftwood, heavy decorations, canister filters, and equipment add weight. Large pieces of rock can add 20-50+ lbs.
Can my floor support a large aquarium?
Standard residential floors support 40 lbs per square foot. Most tanks under 50 gallons are fine. Larger tanks should be near load-bearing walls, on ground floors, or have structural assessment.
Is acrylic much lighter than glass?
Acrylic tanks weigh about 50% less than equivalent glass tanks. However, water (the heaviest component) weighs the same regardless of tank material.
Should I put plywood under my tank stand?
Plywood helps distribute weight and protects flooring. Use 3/4" plywood cut slightly larger than the stand footprint for tanks 40+ gallons.
Can I put a tank on the second floor?
Small to medium tanks (under 40 gallons) are usually fine on upper floors. Larger tanks require evaluation of floor construction, joist spacing, and placement.
Related Calculators
Disclaimer
Weight calculations are estimates. Actual weight varies based on tank manufacturer, decorations, equipment, and water type. For tanks over 55 gallons, consult a structural engineer before placement on upper floors.