Aquarium Volume Calculator
Calculate your aquarium’s volume in cubic feet, water weight, and recommended fish stocking levels with our comprehensive calculator tool.
1. Select Tank Shape
Rectangular
Cylindrical
Bow Front
Corner
2. Enter Tank Dimensions
Aquarium Size Guide
| Tank Size | Common Dimensions (L×W×H) | Volume (Cubic Feet) | Volume (Gallons) | Weight (Full) | Fish Capacity |
|---|---|---|---|---|---|
| Nano | 12″ × 8″ × 8″ | 0.44 | 3.3 | ~30 lbs | 3-5 small fish |
| Small | 20″ × 10″ × 12″ | 1.39 | 10.4 | ~100 lbs | 5-10 small fish |
| Medium | 30″ × 12″ × 18″ | 3.75 | 28.1 | ~250 lbs | 10-15 small/medium fish |
| Large | 48″ × 13″ × 20″ | 7.22 | 54.0 | ~550 lbs | 15-25 medium fish |
| Extra Large | 60″ × 18″ × 24″ | 15.0 | 112.2 | ~1100 lbs | 25-40 medium/large fish |
Note: Fish capacity varies greatly depending on species, filtration, and aquascaping. Always research specific needs of your fish.
Aquarium Volume Information
Understanding Tank Volume
The volume of your aquarium is crucial for:
- Proper Filtration: Filters are rated by gallons – choose one rated for your tank size or larger.
- Heating Requirements: Calculate the wattage needed (typically 5 watts per gallon for freshwater).
- Water Changes: Know exactly how much water to prepare for partial changes.
- Medication Dosing: Accurate measurements ensure proper treatment doses.
- Fish Stocking Levels: Prevents overcrowding and maintains water quality.
Common Conversion Factors
- 1 cubic foot = 7.48 US gallons
- 1 cubic foot = 28.32 liters
- 1 US gallon = 3.785 liters
- 1 cubic foot of freshwater = 62.4 lbs (28.3 kg)
- 1 cubic foot of saltwater = 64.1 lbs (29.1 kg)
Tank Equipment by Size
| Tank Size | Filter Rating | Heater Size |
|---|---|---|
| Up to 10 gallons | 50-100 GPH | 50-75 watts |
| 10-20 gallons | 100-150 GPH | 75-150 watts |
| 20-40 gallons | 150-200 GPH | 150-200 watts |
| 40-60 gallons | 200-300 GPH | 200-300 watts |
| 60+ gallons | 300+ GPH | Two 200+ watts |
Frequently Asked Questions
How accurate is this calculator?
This calculator provides a close approximation of your aquarium’s volume. For rectangular tanks, it’s very accurate. For bow front and corner tanks, it uses geometric approximations that are typically within 2-5% of the actual volume.
How do I determine the ideal stocking level for my aquarium?
While the “one inch of fish per gallon” rule is a common starting point, it’s overly simplistic. Consider these factors:
- Fish species and their adult size
- Swimming habits and territory needs
- Filtration capacity
- Surface area (often more important than volume)
- Aquascaping (rocks, plants, decorations reduce water volume)
Why are my tank’s actual gallons different from what’s advertised?
Commercial aquariums are often labeled by their approximate capacity. A “10-gallon” tank might actually hold 9.6 gallons. Additionally, displacement from substrate, decorations, equipment, and not filling to the absolute top further reduces the actual water volume.
How do I calculate the weight capacity needed for my aquarium stand?
To calculate the total weight your stand must support:
- Water weight (calculator provides this)
- Tank weight (glass/acrylic) – typically 10-15 lbs for small tanks, 20-40 lbs for medium, 50-100+ lbs for large
- Substrate weight (approximately 1.5-2 lbs per gallon)
- Decorations, rocks, driftwood (can be substantial – large rocks may weigh 5-20+ lbs each)
- Equipment weight
Add at least a 20% safety margin to this total.
Related Miscellaneous & Specialized Calculators
Height Conversion
Convert human measurements in feet
Shoe Size Calculator
Convert shoe size to foot length
Stride Length
Calculate stride length in feet
Elevation Gain
Calculate elevation changes in feet
Map Scale Conversion
Convert map scale to actual feet
Surveying Distance
Calculate surveying measurements
Cable/Wire Length
Calculate cable length in feet
Pipeline Length
Measure pipeline length in feet
Aquarium Volume
Calculate volume in cubic feet
Greenhouse Area
Calculate area in square feet