Substrate Depth & Weight Calculator
Estimate how much gravel, sand, or aquasoil you need by tank footprint and desired depth. Get totals in liters, ft³, lb, kg, plus bag counts by common sizes. Optional: slope front↔back and subtract hardscape footprint.
Substrate Needed
Enter footprint and depth to see volume, weight, and bag counts.
How Much Substrate Do I Need?
Volume is footprint area × average depth. In imperial units, cubic feet = (in² × in) / 1728.
Liters = ft³ × 28.3168. Weight depends on bulk density of the product (bagged, loose-packed), not the solid mineral.
Density Reference (Typical Bagged Substrates)
- Quartz gravel: ~90–100 lb/ft³ (1440–1600 kg/m³)
- Sand: ~100–115 lb/ft³ (1600–1840 kg/m³)
- Aquasoil/baked clay: ~50–60 lb/ft³ (800–960 kg/m³)
- Lava rock: ~55–65 lb/ft³ (880–1040 kg/m³)
Aquascaping Tips for Depth & Slope
- Depth: 1–2 in (2.5–5 cm) front, 2–4 in (5–10 cm) back for planted tanks.
- Stability: Use stone terraces, mesh, or retaining wood to hold slopes.
- Roots & Gas: Avoid >4 in (10 cm) of fine sand without plants/snails; risk of anaerobic pockets.
- Cap layers: For nutrient soils, cap lightly with sand/gravel in heavy-flow areas.
FAQs — Gravel, Sand, Aquasoil
How many pounds of gravel per gallon?
Rules of thumb vary (~1 lb/gal), but footprint × depth is more accurate—this tool uses density to convert to lb/kg.
What depth is best for carpeting plants?
Keep the front 1–2 in (2.5–5 cm). Too deep at the front can look bulky and trap debris.
Can I mix sand and soil?
Yes—many aquascapes use a nutrient soil base with a sand/gravel cap for aesthetics and slope control.
