Understanding Aquarium Volume
Knowing your aquarium's exact volume is essential for proper fish stocking, medication dosing, water treatment, and equipment selection. This calculator accounts for substrate displacement and realistic fill levels.
Common Tank Sizes
| Tank Name | Dimensions (LxWxH) | Gallons |
|---|---|---|
| 10 Gallon | 20" x 10" x 12" | 10 gal |
| 20 Gallon Long | 30" x 12" x 12" | 20 gal |
| 29 Gallon | 30" x 12" x 18" | 29 gal |
| 55 Gallon | 48" x 13" x 21" | 55 gal |
| 75 Gallon | 48" x 18" x 21" | 75 gal |
| 125 Gallon | 72" x 18" x 22" | 125 gal |
Fish Stocking Guidelines
| Rule | Guideline | Best For |
|---|---|---|
| 1" per gallon | 1 inch of fish per gallon | Small community fish |
| 1" per 2 gallons | More conservative stocking | Larger fish, beginners |
| Surface area rule | 12 sq in per inch of fish | Oxygen-demanding fish |
Water Weight Reference
- Freshwater: 8.34 lbs per gallon (1 kg per liter)
- Saltwater: 8.56 lbs per gallon (1.025 kg per liter)
- A 55-gallon tank filled weighs over 450 lbs - ensure floor support!
- Add weight of tank, stand, substrate, and decorations
Aquarium Setup Tips
- Substrate: 1-2 inches for most tanks, 2-3 inches for planted tanks
- Filtration: Choose a filter rated for 4-6x your tank volume per hour
- Heater: 3-5 watts per gallon for tropical tanks
- Lighting: Low light for fish-only, high light for planted tanks
- Cycle your tank for 4-6 weeks before adding fish
- Never fill more than 95% to prevent overflow
- Place tank away from direct sunlight to prevent algae
Equipment Sizing Guide
- Filter: GPH should be 4x tank volume minimum
- Heater: 25-50 watts per 10 gallons
- Air pump: 0.033 watts per gallon minimum
- UV sterilizer: Size based on flow rate and tank volume
Frequently Asked Questions
How accurate are the results?
The Aquarium Volume applies a standard formula to your inputs — accuracy depends on how precisely you measure those inputs. For planning and estimation, results are reliable. For high-stakes or professional decisions, cross-check the output with a domain expert or primary source.
Can I use this on mobile?
Yes — the calculator is designed to work on any device. For complex multi-input calculations on small screens, landscape orientation gives more room to see all fields and results simultaneously.
How should I interpret the Aquarium Volume output?
The result is a calculated estimate based on the formula and your inputs. Compare it against the reference values or benchmarks shown on this page to understand whether your result is high, low, or typical. For decisions with real consequences, use the output as one data point alongside direct measurement and professional advice.
When should I use a different approach?
Use this calculator for quick, formula-based estimates. If your situation involves multiple interacting variables, time-varying inputs, or safety-critical decisions, consider a dedicated software tool, professional consultation, or direct measurement. Calculators are most reliable within their stated assumptions — check that your scenario matches those assumptions before relying on the output.