Grout calculator.
Joints measured on the layout, weighed at each maker's own density.
A grout bag's chart assumes an endless grid of whole tiles. This calculator lays your tiles out, cuts included, leaves the wall edge for caulk, and weighs the real joints at the density each maker's chart implies.
0302 / Grout
- Joint area
- 235.4 sq in of joint in 120.0 sq ft
- Joint volume
- 88.3 cu in at 3/8″ deep
- Depth
- 3/8″, the full tile thickness
- By maker
- MAPEI 5.03 lb · LATICRETE 4.98 lb
- Bags
- MAPEI 1 × 10 lb or 1 × 25 lb · LATICRETE 1 × 8 lb or 1 × 25 lb
- Caulk
- 44.0 ft along the walls
- Grout type
- Sanded: 1/8″ is 1/8″ or wider (TCNA's general rule for cement grout; the product's rated range governs)
The range is the two makers' densities; their charts, a full grid, run 13 to 15 percent higher here.
0203 / Layout
ONE SCALE PER CELLTile side over 15″: 1/8″ suits rectified tile; calibrated tile takes 3/16″, check the maker.
Joints by surface
| Surface | Size | Copies | Tiles | Joint area | Joint volume | Grout | Caulk |
|---|---|---|---|---|---|---|---|
| Surface 1 | 12′ 0″ × 10′ 0″ | 1 | 60 laid · 28 cut | 235.4 sq in | 88.3 cu in | MAPEI 5.03 lb · LATICRETE 4.98 lb | 44.0 ft |
Bags by maker
| Grout | Bag | Bags | Left over |
|---|---|---|---|
| MAPEI Ultracolor Plus FA | 10 lb | 1 | 4.97 lb left |
| MAPEI Ultracolor Plus FA | 25 lb | 1 | 19.97 lb left |
| LATICRETE PERMACOLOR Grout | 8 lb | 1 | 3.02 lb left |
| LATICRETE PERMACOLOR Grout | 25 lb | 1 | 20.02 lb left |
The makers' models against the layout
| Basis | Joint volume | Grout | Against the layout |
|---|---|---|---|
| MAPEI · laid-out joints | 88.3 cu in | 5.03 lb | — |
| MAPEI · simple model | 101.3 cu in | 5.77 lb | +14.7 % |
| MAPEI · its 10 lb table, 207 sq ft per bag | — | 5.80 lb | +15.2 % |
| LATICRETE · laid-out joints | 88.3 cu in | 4.98 lb | — |
| LATICRETE · exact grid | 100.0 cu in | 5.64 lb | +13.3 % |
| LATICRETE · its 8 lb table, 170 sq ft per bag | — | 5.65 lb | +13.4 % |
| Simple model over exact grid | × 1.012 | ||
Over 120 square feet the full-grid formulas find 267 to 270 square inches of joint, not 235.4: they count a joint for every tile width, nearly 6 lengthwise and 10 across, where the laid floor has 5 and 9. The caulked wall gap is only 2 of the difference.
The two coverage charts, side by side
Square feet per bag, MAPEI per 10 pounds and LATICRETE per 8, for four formats both chart. LATICRETE's 12 for 24 by 24 inch tile at 1/4 inch is a misprint; its metric column gives 128.
| Tile | 1/16″ | 1/8″ | 3/16″ | 1/4″ | 3/8″ | 1/2″ |
|---|---|---|---|---|---|---|
| 1" x 1" x 1/4" | 39 / 34 | 20 / 19 | 13 / 14 | 10 / 11 | 7 / 8 | 5 / 7 |
| 12" x 12" x 3/8" | 311 / 254 | 156 / 128 | 104 / 86 | 78 / 65 | 52 / 44 | 39 / 33 |
| 12" x 24" x 3/8" | 414 / 338 | 207 / 170 | 138 / 114 | 104 / 86 | 69 / 58 | 52 / 44 |
| 24" x 24" x 3/8" | 621 / 505 | 311 / 254 | 207 / 170 | 156 / 128* | 104 / 86 | 78 / 65 |
| Maker | Joint model | Median | p10–p90 | Cells | Joint range |
|---|---|---|---|---|---|
| MAPEI Ultracolor Plus FA | Simple, crossings twice | 98.5 | 96–98.9 | 128 | 1/16–3/4″ |
| LATICRETE PERMACOLOR Grout | Exact grid | 97.5 | 96.5–98.7 | 138 | 1/16–1/2″ |
Figures from search answers, checked
| Source | Claim | Makers' tables | Verdict |
|---|---|---|---|
| tileprodepot.com | 25 lb covers 60-80 sq ft (12 × 12 in tile, 1/8 in joint) | LATICRETE 400 sq ft; MAPEI 388 | a fifth or less |
| flacksflooring.com | 7-9 lb per 100 sq ft (12 × 24 in tile, 1/8 in joint) | LATICRETE 4.7 lb; MAPEI 4.8 (3/8 in thick) | 1.4 to 1.9 times the makers |
One kitchen, 12 by 10 feet: 5 pounds of grout
Tiles of 24 by 12 inches run along the 12-foot wall with 1/8-inch joints and a 1/4-inch gap at the walls: 6 columns, 10 rows, 60 tiles, 28 cut. Five joints of 119.5 inches and nine of 143.5, less 45 crossings counted once, make 235.4 square inches; at 3/8 inch deep, 88.3 cubic inches. That is 4.98 pounds at LATICRETE's density and 5.03 at MAPEI's, one bag of 8 or 10 pounds.
Depth, and the edge that takes caulk
Filled to the two thirds of the depth MAPEI keeps clear, the joints take 3.32 to 3.35 pounds. The 44 feet along the walls take caulk, not grout, as TCNA advises where the floor meets the wall.
Questions asked before buying grout
How do I calculate how much grout I need?
Joint area times depth gives a volume, and the powder weighs about 97.5 to 98.5 pounds per cubic foot of joint in the two makers' charts read here. This page takes the joint area from the actual layout, cuts included and the caulked wall edge left out. The 12 by 10 foot example kitchen in 24 by 12 inch tile comes to about 5 pounds.
How many sq ft does a 25 lb bag of grout cover?
Anything from 17 to 2,104 square feet in LATICRETE's 25-pound chart for PERMACOLOR, from a 1-inch penny round with 1/2-inch joints to 24 by 48 inch tile with 1/16-inch joints. For 12 by 12 by 3/8 inch tile at 1/8 inch it is 400 square feet, and MAPEI prints 388 for 25 pounds of Ultracolor Plus FA. The 60 to 80 square feet one search answer quotes for that tile is a fifth or less of both.
How much grout do I need for 12x24 tile?
At 3/8 inch thick with 1/8-inch joints, LATICRETE's chart covers 170 square feet with an 8-pound bag and MAPEI's 207 with 10 pounds: 4.7 and 4.8 pounds per 100 square feet. The 7 to 9 pounds per 100 square feet quoted in a search answer is one and a half to nearly two times that. By the layout, a 12 by 10 foot kitchen takes about 5 pounds.
How much coverage does a 10 lb bag of Mapei grout provide?
MAPEI's chart for Ultracolor Plus FA runs from 4 square feet per 10 pounds (1-inch mosaic, 5/8- to 3/4-inch joints) to 828 (32 by 32 inch tile, 1/16-inch joints); 12 by 12 by 3/8 inch tile gets 311 at 1/16 inch, 156 at 1/8 and 78 at 1/4. Its figures follow one formula within rounding, (L + W) × joint × depth ÷ (L × W), at about 98.5 pounds of powder per cubic foot of joint.
How many sq ft per bag of grout?
It is not one figure. Per 8-pound bag of LATICRETE PERMACOLOR the chart goes from 6 square feet (1-inch penny round, 1/2-inch joints) to 673 (24 by 48 inch tile, 1/16-inch joints). Enter the tile, the joint and the depth, and the page gives the pounds for your area and the bags each maker sells.
How much grout for 200 sq ft?
It depends on the tile. For 200 square feet of 12 by 24 by 3/8 inch tile with 1/8-inch joints, LATICRETE's chart gives 9.4 pounds and MAPEI's 9.7: one 10-pound bag, or two of 8. For 12 by 12 by 3/8 inch tile at the same joint it is 12.5 and 12.8 pounds, and a 1-inch mosaic with 1/4-inch joints takes about 145 pounds by LATICRETE's chart.
What is the best spacing for grout between 12x24 tiles?
The spacer sets it. For tile with a side over 15 inches, Daltile's guidance is 1/8 inch for rectified tile and 3/16 inch for calibrated, and the Ceramic Tile Education Foundation publishes a 33 percent limit on the offset of such tile. The tile maker's instructions govern.
Should grout sit flush with tile?
Yes, by MAPEI's data sheet: the grout surface should be flush with the tile edge. It also asks for two thirds of the tile's depth to be left clear of mortar, so the grout is two thirds to the full thickness deep; both makers' charts count the full thickness. The page gives both ends.
Is a 1/16 grout line suitable for 12x24 tile?
It is the narrowest joint either product lists, but Daltile's guidance for tile with a side over 15 inches is wider: 1/8 inch for rectified tile, 3/16 for calibrated. TCNA adds that many people feel a joint under three times the average size variation between tiles looks irregular.
How wide is a grout joint?
As wide as the tile needs, within the product: MAPEI sells Ultracolor Plus FA for joints from 1/16 to 3/4 inch and LATICRETE PERMACOLOR for 1/16 to 1/2. For cement grout the width also picks the type: TCNA keeps unsanded grout under 1/8 inch and sanded grout from 1/8 inch up, unless the product is rated across that line, as both of these are.
Is sanded grout ok in a shower?
The joint width decides more than the room: TCNA's answer for cement grout is sanded from 1/8 inch up and unsanded below. Neither TCNA's grout page nor the two data sheets read here give a separate rule for showers; the product's instructions for wet areas govern.
Can I use unsanded grout on 1/4 inch?
TCNA's general answer for cement grout is no: joints of 1/8 inch and larger should only take sanded grout. Some cement grouts are rated across that line, though: MAPEI's Ultracolor Plus FA, whose fine aggregate it says allows narrow joints, for 1/16 to 3/4 inch, and LATICRETE PERMACOLOR for 1/16 to 1/2. Follow the range on the bag.
What the estimate leaves out
- One tile size and joint for the whole job; mixed formats need a run each.
- Surfaces are rectangles; openings, cabinets and curved edges are not subtracted.
- The densities are derived from each maker's coverage chart, not printed by the makers, and belong to those two products.
- Cement grout only; epoxy and ready-mixed grouts have their own charts and are not modeled.
- The caulk length is the whole perimeter, doorways included; no caulk quantity is given.