Even depth
Substrate liters = length × width × depth ÷ 1,000, with all dimensions in centimeters. A 60 × 30 cm footprint with an even 5 cm bed needs 9 liters before settling or spare material.
Aquarium substrate calculator
Use this aquarium substrate calculator to work out how many liters of sand, gravel or aquasoil to buy. Enter your tank dimensions and intended depth, including a front-to-back slope, then carry the setup into your scape.
How this estimate worksYour tank
Start with what you haveDimensions
Use label dimensions for an estimate. For a closer measurement, use inside dimensions and your water height.
Substrate depth
Not setEven depth uses the same value at the front and back. Fractions such as 2 1/4 work too.
Enter tank dimensions to use an estimate.
Your substrate quantity
Free · No sign-upStart with your tank
Choose a standard tank or enter length, width and height.
Water estimate
See how much water is left after substrate.
Substrate quantity
Estimate how much to buy for your depth.
How the aquarium substrate calculator works
The calculation uses your rectangular tank’s footprint and the depth of the bed. Use inside length and width for a closer estimate. Tank height keeps the setup valid for the water estimate and the planner; it does not change substrate quantity for the same footprint and depths.
A front-to-back slope
Use average depth = (front + back) ÷ 2. At 4 cm in front and 8 cm at the back, the same 60 × 30 cm footprint needs 10.8 liters. This assumes a straight slope across the full footprint.
The aquarium substrate calculator accepts centimeters, decimal inches and fractions such as 2 1/4. Inches are converted to centimeters before calculating. The result is a volume of material, not a weight.
How many bags should you buy?
Bags labeled in liters
Divide the calculated liters by the volume per bag and round up. For a 10.8 L bed, 3 L bags mean four bags; 9 L bags mean two. These are arithmetic examples, not a recommendation for a particular product. Compare package sizes and how much spare material you want.
Bags labeled in kilograms or pounds
Check the manufacturer’s stated volume or bulk density for that material. There is no single conversion from liters to kilograms that works for sand, gravel and aquasoil. This aquarium substrate calculator does not invent a density or a bag weight.
Compare substrate materials and product properties before ordering. For depth decisions rather than quantities, read how to choose substrate depth and work out how much to buy.
What to adjust for your layout
Mounds, valleys and material under rocks
A central mound, valley, terrace or separate sand path is not a full-width straight slope. Measure distinct areas separately and add their volumes. Material displaced by buried stones or raised supports is not subtracted automatically.
Settling and planting depth
The displayed quantity does not include an extra purchasing margin. Choose that margin for your material and intended shape. Pick depth from the plants and the manufacturer’s instructions; the optional 6 cm estimate is an editable example, not a universal planting recommendation.
Aquarium substrate calculator questions
Can I use this for sand, gravel and aquasoil?
Yes, the geometric volume formula applies to each. Choose your own depth and check the package volume. Grain size, compaction and material density affect how closely the bag contents match the finished bed.
Why is there also a water estimate?
The same bed occupies space inside the aquarium. Estimated water subtracts substrate volume from rectangular tank volume and then applies the existing 8% allowance for hardscape and space below the rim. It is a planning estimate, not the actual fill volume for dosing.
Will changing tools lose my setup?
Use the result’s stocking link to carry over your dimensions, depths and any saved animal counts. A copied setup link returns to this aquarium substrate calculator. Opening a new 3D plan carries those conditions into a new tank.
Check water volume or livestock next
Use the aquarium volume calculator to compare nominal capacity, rectangular volume and estimated water. Use the aquarium stocking calculator to review your fish, shrimp and snail selection against the water available.
From a calculation to your tank plan
The calculator answers a specific sizing question. In the planner, keep your own choices and place plants, rocks and wood by hand. Review light, CO₂, water conditions and substrate material before requesting an optional analysis.
Read how Scapesome checks a tank · Choose another aquarium calculator