Aquarium gravel calculator

The old 1 lb/gal for roughly 1 inch and 1.5–2 lb/gal for 2 inches rules are loose shopping shortcuts. Here a 2-inch bed is 2.08 lb per nominal gallon. Footprint and bulk density explain the difference. Gravel and sand use 100 lb/ft³; aquasoil uses 60. Check bag coverage; grain size and moisture change density.

Worked example: 20 gallon long

30 × 12 × 2 = 720 in³. Divide by 1,728 and multiply by 100 lb/ft³ = 41.67 lb. Round up to 3 bags of 20 lb.

Bulk densities are stated planning assumptions; litre conversion: NIST conversion tables

Choose a tank size

• 2.5 gallon12 × 6 × 8 in
• 5 gallon16 × 8 × 10 in
• 5.5 gallon16 × 8 × 10 in
• 10 gallon20 × 10 × 12 in
• 13 gallon widescreen24 × 8 × 19 in
• 15 gallon24 × 12 × 12 in
• 15 gallon column13.75 × 13.62 × 25 in
• 20 gallon high24 × 12 × 16 in
• 20 gallon long30 × 12 × 12 in
• 20 gallon extra high20 × 10 × 24 in
• 25 gallon24 × 12 × 20 in
• 29 gallon30 × 12 × 18 in
• 30 gallon36 × 12 × 16 in
• 33 gallon long48 × 13 × 13 in
• 37 gallon30 × 12 × 22 in
• 38 gallon36 × 12 × 20 in
• 40 gallon breeder36 × 18 × 16 in
• 40 gallon long48 × 12 × 16 in
• 45 gallon36 × 12 × 24 in
• 50 gallon36 × 18 × 19 in
• 55 gallon48 × 13 × 21 in
• 60 gallon breeder48 × 18 × 16 in
• 65 gallon36 × 18 × 24 in
• 75 gallon48 × 18 × 21 in
• 90 gallon48 × 18 × 24 in
• 110 gallon48 × 18 × 30 in
• 120 gallon48 × 24 × 24 in
• 125 gallon72 × 18 × 21 in