Aquarium Estimator Tools

How Much Gravel or Sand Do I Buy for My Fish Tank?

Calculate how much weight of gravel or sand needed for a fish tank

So, you are ready to buy gravel or sand for your newest aquarium. You know how many inches you need, but the bags are sold by what?

We can help. Just enter the dimensions of the bottom of your tank and the desired depth of substrate to get the weight of gravel, dry sand or wet sand. The results use standard material weights. This is only an estimate. Actual volume may vary due to variables we cannot predict, such as average size of gravel pieces or moisture content, but in most cases such differences will result in small differences in final depth.

Aquarium Substrate Weight Calculator

To use this calculator, enter the size of your aquarium and the desired depth of the substrate. The substrate weight will be calculated for you.

Width of Tank  inches

Length of Tank  inches

Inches of Substrate 

Gravel Required: lbs.

Dry Sand Required: lbs.

Wet Sand Required: lbs.

Frequently Asked Questions

How thick should the sand or gravel layer be?

Two inches is a typical recommendation, with fish-keepers using a range of 1" to 2.5" for a fish-only tank. For a planted tank, you'll need an additional 1" nutrient layer below the sand or gravel, as described below in this FAQ.

Should I use sand or gravel?

In short, either is suitable. Sand is popular with serious aquarists, though aquarium gravel is still widely used. Sand is more natural-looking, and, with proper filtration, easier to keep clean. Waste sits on the surface rather than falling deep into the substrate. Well-positioned filters can pull waste from the surface, reducing the need to vacuum. Care must be taken to avoid sucking sand into filters and aquarium vacuums. Gravel needs to be cleaned more often but stays in place better in cleaning or if you have fish who like to stir up the substrate. If you are using under-gravel filtration, gravel is required.

What kind of sand should I get?

Children's play sand is sanitized and ready to use; it is available inexpensively from home improvement stores. Sand-blasting sand is coarser and is mostly quartz, but will need rinsed. Builder's sand is dirty and should be avoided. Of course, sand can be purchased at fish keeper stores. They may have more options in color or texture, but may be more expensive.

What kind of gravel should I get?

Purchase gravel pre-cleaned from a fish keeper's store. Avoid painted gravel (called "clown barf" by fish-keepers) because the paint can come off to injure the fish and it looks silly anyway.

What kind of substrate do I need for a planted tank?

A planted tank needs about a one-inch nutrient layer on the bottom (vermiculite or laterite), covered by about a two-inch layer of gravel or sand to protect nutrients from washout and to hold plants in place. Laterite happens to be an ingredient in traditional non-clumping cat litter, but purchase laterite that is prepared for aquariums; cat litter may have perfumes or clumping agents. Also available are prepared substrates with blends of components selected for planted tanks.

This FAQ is a simple summary. For more information on substrate selection, we recommend this article on substrate for aquariums. For more information on fish keeping for beginners, see The Complete Aquarium by Peter W. Scott.