Mosaic Grout Volume Calculator

How to use this estimate

The estimate models a repeating square-tile grid. Joint fraction is based on the void area in a square module; actual mosaic sheet spacing, edge joints, irregular pieces, substrate absorption, and grout product yield vary. Use the product's published yield or measured density for purchasing; this arithmetic is not installation guidance.

Method

Open fraction = 1 - (tile width / (tile width + joint width))². Joint volume = area × 144 × depth / 1728 × open fraction. Convert to mass with entered density, apply chosen reserve, and round packages upward.

Worked example

For 25 sq ft of 1 in tile, ⅛ in joints, ⅜ in depth, and entered density 100 lb/cu ft, the modeled grout is 16.40 lb; a selected 10% reserve requires 2 ten-pound packages.

Assumptions and supported inputs

Use measured dimensions and the listed field ranges. Values outside those bounds, missing entries, non-finite numbers, and fractional counts where a whole number is required are rejected. Displayed results are rounded to two decimal places; internal calculations retain full precision. This is a planning estimate, not a substitute for an on-site layout, product instructions, or a qualified trade decision where applicable.

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Northstar Calculators provides this arithmetic for scenario planning. Verify the assumptions and physical fit before buying or building.