# Tile Adhesive and Grout Calculator: Bags and Kilograms

> Tile adhesive is estimated from the consumption on its data sheet, in kg per square metre for the trowel notch used, times the tiled area. Grout is estimated from the volume of the joints: joint length per square metre, from the tile size, times joint width and depth, times the grout's density. Both get a wastage allowance.

## What it calculates

For a tiled floor or wall, the calculator gives:

- the **tiled area** in square feet and square metres;
- the **tile adhesive** in kilograms and whole bags;
- the **grout** in kilograms, and the grout consumption in kg per square metre.

To count the tiles themselves, use the [flooring quantity calculator](/calculators/flooring-quantity-calculator).

## Inputs

**Tiled area** is in square feet, less any openings; the square metre figure is shown under
the field.

**Tile length** and **tile width** are in millimetres.

**Joint width** is the spacer or joint width in the tiling specification, in millimetres.

**Tile thickness** is in millimetres and is used as the depth of the grout joint.

The **assumptions** panel holds the adhesive consumption, the adhesive bag size, the grout
density and the wastage allowance.

## Method

1. Area in m² = area in sq ft × 0.092903.
2. Adhesive = area in m² × consumption in kg/m² × (1 + wastage).
3. Adhesive bags = adhesive ÷ bag size, rounded up.
4. Grout in kg/m² = (L + W) / (L × W) × joint width × joint depth × density.
5. Grout = area in m² × grout in kg/m² × (1 + wastage).

In step 4, L, W, the joint width and the joint depth are in millimetres and the density is in
kg/dm³ (the same as kg per litre). (L + W) / (L × W) is the length of joint in each unit of
tiled area. Multiplied by the joint's width and depth it gives the depth of grout spread over
the area in millimetres, and 1 mm over 1 m² is 1 dm³, so multiplying by the density gives kg
per square metre.

## Assumptions

| Assumption | Default | Notes |
| --- | --- | --- |
| Adhesive consumption | 5 kg/m² | Illustrative starting value: replace with the figure on your product's data sheet for your trowel notch |
| Adhesive bag size | 20 kg | Check the bag size of the product you are buying |
| Grout density | 1.6 kg/dm³ | Illustrative starting value: replace with the figure on your product's data sheet |
| Wastage | 10% | Material left in the bucket, spillage and cleaning off |

The adhesive consumption is the input that matters most. It can vary several-fold between a
small notch on a flat wall and a large notch on a floor laid with large-format tiles.

## Limitations

- **One tile size and joint width at a time.** Run each tile type separately.
- **Joint depth is taken as the tile thickness.** Where the joint is shallower, enter the
  actual depth.
- **The adhesive figure is only as good as the data sheet value.** A surface out of level, or
  back-buttering of large tiles, raises consumption above the data-sheet figure.
- **Movement joints are not deducted.** Perimeter and field movement joints are filled with
  sealant, not grout, as the tiling specification sets out.
- **It does not choose the adhesive or the grout.** The adhesive class, and a cement or
  reaction resin (epoxy) grout, are a specification decision for the tile, background and use.

## Worked example

500 sq ft of 600 × 600 mm tiles, 9 mm thick, with 3 mm joints, adhesive at 5 kg/m² in 20 kg
bags, grout at 1.6 kg/dm³ and 10% wastage:

| Step | Calculation | Result |
| --- | --- | --- |
| Area | 500 × 0.092903 | 46.45 m² |
| Adhesive | 46.45 × 5 × 1.10 | 255.5 kg |
| Adhesive bags | 255.5 / 20, rounded up | 13 |
| Grout per m² | (600 + 600) / (600 × 600) × 3 × 9 × 1.6 | 0.144 kg/m² |
| Grout | 46.45 × 0.144 × 1.10 | 7.4 kg |

The floor needs **13 bags of adhesive and about 7.4 kg of grout**. With 300 × 300 mm tiles of
the same thickness and joint, the grout doubles to 0.288 kg/m², or about 14.7 kg.

## How engineers use it

On a fit-out, tiling is measured from the drawings in square metres for each tile type, and
the specification names the adhesive class, the trowel notch, the joint width, the grout type
and the movement joints. Adhesive and grout quantities then follow from the manufacturers'
data sheets for those products. A calculation like this one is the quick check that a
supplier's or tiler's material estimate is in the right range.

## When a professional design must replace it

Use the calculator to estimate how much adhesive and grout to buy, or to check an estimate.
Replace it with a measured take-off and a written tiling specification for a whole building,
for wet areas, external or facade tiling, heavy or large-format tiles, and chemical or
hygiene areas. The tiling specification and the products' data sheets, not a rule of thumb,
decide what is used.

## Frequently asked questions

### How many bags of tile adhesive do I need?

Multiply the tiled area in square metres by the adhesive consumption on the data sheet, in kg per square metre for your trowel notch, add a wastage allowance and divide by the bag size, rounding up. 500 sq ft (46.45 m²) at 5 kg per square metre with 10% wastage is 255.5 kg, or 13 bags of 20 kg.

### How do you calculate grout quantity?

Grout in kg per square metre = (L + W) / (L × W) × joint width × joint depth × density, with tile length L, tile width W, joint width and depth in mm and density in kg/dm³. For 600 × 600 mm tiles with 3 mm joints 9 mm deep and grout at 1.6 kg/dm³, that is 0.144 kg per square metre before wastage.

### Why does adhesive consumption vary so much?

It depends mainly on the trowel notch, which is chosen for the tile size and the flatness of the surface. Larger tiles, uneven backgrounds and back-buttering the tile all need more adhesive. The data sheet gives the consumption for each notch size, so take the figure for the notch you will actually use.

### Why do small tiles need more grout?

Smaller tiles mean more joints in every square metre. Halving the tile size in both directions doubles the joint length per square metre, and so doubles the grout for the same joint width and depth. That is why mosaics use far more grout than large-format tiles.

### Is the tile thickness the right joint depth?

It is the usual assumption and a slightly generous one, since part of the joint below the tile edge is taken up by adhesive. Where the specification sets a shallower grout depth, for example a joint raked out for a sealant, enter that depth instead.

## Sources

- [IS 15477](https://standards.bis.gov.in/website/published-standards/department-wise) — Adhesives for use with ceramic, glass and stone tiles — specification
- [EN 12004-1](https://standards.cencenelec.eu/ords/f?p=CEN:105) — Adhesives for ceramic tiles — requirements, classification and marking
- [EN 13888-1](https://standards.cencenelec.eu/ords/f?p=CEN:105) — Grouts for ceramic tiles — requirements, classification, designation, marking and labelling

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Source: https://hagerstone.com/calculators/tile-adhesive-grout-calculator