Grout Calculator
Size sanded or unsanded cement grout from your tiled area, tile dimensions, and joint size. Joint depth follows tile thickness until you override it.
Formula example
For 100 ft² of 12×12 in tile with 1/8 in joints and 3/8 in depth at 100 lb/ft³ sanded grout, the perimeter formula gives 6.51 lb before waste. With 10% waste you need 7.16 lb—1 bag at 25 lb each.
Sanded versus unsanded
Sanded grout suits wider joints; unsanded suits narrow joints and polished stone. Densities default to 100 and 95 lb/ft³ but you can type a lab value from the bag.
Trust the bag label
Manufacturer coverage tables include product-specific fluff and mineral content. Use this calculator for a geometry-based starting point, then confirm pounds and square feet on the package before checkout.
FAQ
What formula does this use?
The perimeter form ((L+W)/(L×W)) × joint width × joint depth × area converts joint volume to pounds. On 100 ft² of 12×12 tile with 1/8 in by 3/8 in joints at 100 lb/ft³, that is 6.51 lb before waste and 7.16 lb with 10% waste.
Why can 4×4 tile need more grout than 12×12?
Smaller tiles have more joint length per square foot. The same 100 ft² at 4×4 with 1/8 in by 1/4 in joints is about 13.02 lb before waste—double the large-format example.
Does thinset change the result?
Yes in the field—mortar can occupy part of the joint. This page estimates dry cement grout only; use your bag coverage table as the final check.
Is epoxy grout included?
No. Only cementitious sanded and unsanded grout are modeled. Epoxy systems need the manufacturer’s coverage chart.
How do I arrive from the tile calculator?
Use the grout link on the tile results. It passes net area, tile size, and joint width. Joint depth stays at the 3/8 in default unless you add jd in the URL or edit it here.
When do I need more than one bag?
Bags round up after waste. Large floors with small tile can cross several 25 lb bags—500 ft² of 4×4 tile is about 72 lb to buy, or three bags in the reference case.
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By Home Yard Calc Editorial Team · Sources listed on the methodology page · Last updated October 26, 2026
Estimates only. Densities, coverage and salt targets vary by product, moisture and manufacturer. Confirm with your supplier or equipment manual. Not a substitute for professional design, soil engineering or pool service.