Thinset Mortar Calculator

Measured area (sq ft). Enter the tile surface being installed with this mortar. Measure the actual floor or wall area before adding allowance. Different mortars, installation methods or substrate conditions should be estimated separately.

Coverage per bag (sq ft). Enter the square feet one bag should cover under the intended installation conditions. Use the product’s guidance for the trowel, tile and substrate, then account for back-buttering and required contact as applicable. Trowel notch size alone does not establish a universal coverage rate.

Dry material per bag (lb). Enter the dry weight of one bag of the mortar used for the coverage figure. The weight result represents purchased whole bags. It does not include mixing water or establish the mortar’s installed density.

Allowance (%). Enter the percentage you want to add for cutting, handling loss or other conditions specific to this work. Apply it to the measured quantity rather than enlarging the measurements as well. The suggested value is editable, not a universal recommendation; enter zero when no allowance is needed.

Required coverage includes the allowance. Bags round that demand upward using the entered product yield, and purchased weight is the dry weight of the whole bags. Check actual mortar transfer and coverage during installation; this estimate does not select a trowel or verify contact.

Required coverage = tiled area × allowance factor. Bags = ceil(required coverage ÷ product coverage per bag). Purchased weight = bags × bag weight.

Worked example: 200 sq ft plus 10% allowance is 220 sq ft. At an illustrative 50 sq ft per 50 lb bag, buy 5 bags (250 lb). Enter your actual product rate.

Trowel notch size alone does not establish yield. Mortar, tile profile, required contact, back-buttering and substrate flatness affect coverage. No universal coverage or trowel recommendation is supplied.

Reference guidance

MAPEI product-specific material calculators. Consult the relevant product or estimating instructions. The illustrative numbers above are not specifications for the linked products.