About aquariumsubstratecalculator.com

Aquarium Substrate Calculator is a small, focused tool site for aquarium keepers. We build calculators that answer one specific question properly, rather than a wall of half-finished widgets.

Why we built it

Buying substrate is one of the few parts of setting up an aquarium where a wrong guess costs real money and a second trip to the shop. Most keepers end up either over-buying two spare bags or scraping the bottom of the bag halfway through a layout. The maths is simple — footprint, depth, density — but nobody wants to do long division in a shop car park.

So we put the whole chain behind a single page. Enter the inside dimensions, choose the depth, pick the material, and the tool returns pounds, kilograms, litres and a bag count you can act on immediately.

What makes this different

Plenty of sites publish a gravel calculator inside a five-thousand-word article and bury the input fields under three screens of advertising. We inverted that: the calculator is the first thing on the page, it loads without any third-party scripts, and the reference tables and guides sit underneath for the people who want to check the working.

• Material-specific densities for gravel, sand, pea gravel and aquarium soil.
• Both an even bed and a sloped front-to-back layout.
• Metric and imperial throughout, converted live as you type.
• Bag counts for the packaging sizes you can actually buy.
• Shareable results — the URL updates so you can send your numbers to someone else.

How we source our numbers

Densities are typical loose, dry, settled figures used across the aquarium trade: about 100 lb per cubic foot for aquarium gravel, 90 for sand and roughly 40 for lightweight planted soils. Real bags vary by brand, grain size and how much moisture the material is carrying, so treat every result as a well-informed estimate and check the label before you buy.

Get in touch

Spotted a wrong density, want a tank size added to the presets, or have a feature request? We read everything — head to the contact page and send us a note.