Sand calculator
Aquarium sand calculator
Sand packs tighter than gravel, so a bed of the same depth weighs less than you expect. Get the exact poundage before you buy, and avoid the second trip.
Substrate calculator
How much sand do I need?
Calculated at 90 lb per cubic foot — typical for dry, loosely settled aquarium sand.
Result
of aquarium gravel needed
- Metric weight
- 0 kg
- Volume
- 0 in³
- Water volume
- 0 L
- Bags to buy
- 0
Guide
Sand is lighter than gravel, but not by much
Sand grains are finer and pack more tightly than open-grain gravel, so the volume you buy goes further — but the material itself is only about 10 % lighter per cubic foot. Where gravel settles at roughly 100 pounds per cubic foot, aquarium sand comes in near 90. A two-inch bed in a 20 gallon long, with its 30 × 12 inch floor, needs about 38 pounds of sand against 42 pounds of gravel.
That is why a substrate aquarium calculator has to know which material you are pouring. Guessing gravel weights for a sand tank leaves you with a spare bag; guessing sand weights for a gravel tank leaves you short at the end of the scrape.
How deep should sand be?
One to two inches suits most fish-only tanks, and two inches is the practical maximum for fine sand in a heavily trafficked community setup — deeper beds compact, and the surface layer can go stale where waste settles. Burrowing species such as corydoras, kuhli loaches and certain gobies appreciate two to three inches so they can actually disappear into the substrate, which is worth allowing for even though it means more material.
Sand also behaves differently when you slope it. It creeps back down towards the front glass over a few weeks, so build the slope a little steeper than you want the finished look to be, and expect to top it up once it settles.
Wash it before you pour
New sand carries a lot of rock dust. Rinse it in a bucket of cool water, stirring hard and decanting the cloudy water, until it runs clear — five or six changes is normal for a fine grade. Skipping this is the single most common reason a freshly set-up tank stays milky for a week.
Working out depth from a weight you already own? Use theaquarium substrate depth calculator. For planted tanks where nutrients matter more than texture, compare theaquarium soil substrate calculator, or head back to the full aquarium substrate calculator.