Custom Building Products grout calculator

100 ft² of 12 × 24 in tile, 3/8 in thick, 1/8 in joint

Polyblend Sanded 1× 25 lb bag 5.4 lb · 461 ft² each · chart
Prism 1× 17 lb box 3.7 lb · 461 ft² each · chart

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Joint

Custom Building Products coverage chart

Polyblend Sanded: ft² per 25 lb bag. Joint width across, tile down.
Tile	1/8	3/16	1/4	3/8	1/2
1 × 1 in1/4 in thick	54	40	33	27	24
2 × 2 in1/4 in thick	96	68	54	40	33
3 × 3 in1/4 in thick	138	96	74	54	43
4.25 × 4.25 in1/4 in thick	192	131	101	71	56
6 × 6 in1/4 in thick	266	181	139	96	75
8 × 8 in3/8 in thick	234	158	121	83	64
12 × 12 in3/8 in thick	348	234	177	121	92
16 × 16 in3/8 in thick	462	310	234	158	121
18 × 18 in3/8 in thick	518	348	262	177	135
20 × 20 in3/8 in thick	574	385	291	196	149
24 × 24 in3/8 in thick	688	461	348	234	177
6 × 24 in3/8 in thick	279	189	143	98	75
12 × 24 in3/8 in thick	461	310	234	158	121
6 × 36 in3/8 in thick	299	202	153	104	80
9 × 36 in3/8 in thick	416	279	211	143	109
12 × 48 in3/8 in thick	552	370	279	189	143

Scroll sideways for every joint. Computed cells are set in italics.

Prism: ft² per 17 lb box. Joint width across, tile down.
Tile	1/16	1/8	3/16	1/4	3/8	1/2
1 × 1 in1/4 in thick	96	54	40	33	27	24
2 × 2 in1/4 in thick	181	96	68	54	40	33
3 × 3 in1/4 in thick	266	138	96	74	54	43
4.25 × 4.25 in1/4 in thick	372	192	131	101	71	56
6 × 6 in1/4 in thick	521	266	181	139	96	75
8 × 8 in3/8 in thick	461	234	158	121	83	64
12 × 12 in3/8 in thick	688	348	234	177	121	92
16 × 16 in3/8 in thick	915	462	310	234	158	121
18 × 18 in3/8 in thick	1,028	518	348	262	177	135
20 × 20 in3/8 in thick	1,142	574	385	291	196	149
24 × 24 in3/8 in thick	1,369	688	461	348	234	177
6 × 24 in3/8 in thick	552	279	189	143	98	75
12 × 24 in3/8 in thick	915	461	310	234	158	121
6 × 36 in3/8 in thick	591	299	202	153	104	80
9 × 36 in3/8 in thick	824	416	279	211	143	109
12 × 48 in3/8 in thick	1,096	552	370	279	189	143

Scroll sideways for every joint. Computed cells are set in italics.

Sizes and joints not on Polyblend Sanded's chart are computed from the joint volume, with a density fitted to that chart.

Sizes and joints not on Prism's chart are computed from the joint volume, with a density fitted to that chart.

Other brands

Sources

Figures built September 2026.

Where these numbers come from (3)

Coverage: Custom Building Products, “Polyblend® Sanded Grout / TDS-129”, 3/22/2023, retrieved from https://www.custombuildingproducts.com/TDS/TDS-129.pdf on 2026-09-24. Chart values are restated as numbers; no text or table is reproduced.
Coverage: Custom Building Products, “Prism® Ultimate Performance Grout / TDS-128”, 6/20/2023, retrieved from https://www.custombuildingproducts.com/TDS/TDS-128.pdf on 2026-09-24. Chart values are restated as numbers; no text or table is reproduced.
Grout waste: LATICRETE, “SpectraLOCK PRO Grout Installation & Maintenance Guide, TDS 400 PRO”, R 9 October 2009, retrieved from https://cdn-global.laticrete.com/-/media/project/laticrete-international/shared/files/support-and-downloads/technical-datasheets/tds400-pro.ashx?la=en on 2026-09-24. Chart values are restated as numbers; no text or table is reproduced.

Quantities are estimates for buying materials. Actual use depends on tile variation, joint depth and installation; manufacturers publish their coverage figures for estimating only.