How to use this calculator
- 1Enter the area you are tiling.
- 2Choose how the tiles are fixed: tile adhesive with a notched trowel, or a cement–sand mortar bed.
- 3For adhesive, choose your tile size — it picks the trowel notch. If your adhesive bag gives a usage rate, type it in to replace ours.
- 4For a mortar bed, enter the bed thickness, the mix and your cement bag size.
The formula
- 01Adhesive = (rate + back-buttering) × area × (1 + extra %)
- 02Bags = adhesive ÷ bag size, rounded up
- 03Mortar bed: dry volume = area × bed thickness × (1 + extra %) × 1.33
- 04Cement = dry volume ÷ (1 + sand parts) × 1,440 kg/m³ + slurry × area; sand = dry volume × sand parts ÷ all parts
A bigger notch leaves thicker ridges of adhesive, so it uses more per square metre. Our defaults — 2 kg/m² for mosaics, 3.1 for a 6 mm (¼ × ¼ in) notch, 4 for 8 mm, 5 for 10 mm and 7 for a 12 mm (½ × ½ in) notch — follow LATICRETE's published coverage (for example 35 ft² per 50 lb bag with a ½ × ½ in trowel, which is 7 kg/m²).
Large tiles are also back-buttered: a thin coat on the tile's back makes sure it is fully bedded. That coat is about 1 mm thick, which uses about 1.3 kg/m² of powder (254 Platinum mixes 3.6 : 1 with water and weighs 1.65 kg per litre wet); we allow 1.5.
Floors in Pakistan, India and the Gulf are usually laid on a bed of cement–sand mortar instead. For 100 ft² (9.3 m²) at 1.5 in (38 mm) in a 1 : 3 mix, the bed alone needs about 3.4 bags of 50 kg cement (buy 4) and 12.5 ft³ of sand — the same as the usual worked examples. The cement slurry the tiles are pressed into comes on top: India's CPWD consumption figures for tiles on a 20–25 mm bed are about 4 kg/m² above the bed mortar alone.
Worked example
3 m × 2 m with a 6 mm notch at 3.1 kg/m² plus 10% extra needs 20.5 kg.
That's 2 bags of 20 kg.
Tips before you buy
- Check coverage by lifting a freshly laid tile: the back should be well covered (most guidance asks for near-full coverage on floors and in wet areas).
- Use flexible (S1) adhesive on wooden floors, underfloor heating and large-format tiles.
- Don't mix more than you can use within the pot life on the bag.
- On a mortar bed, lay only as much bed and slurry as you can tile before the slurry dries, and keep the floor damp for a few days afterwards.
Frequently asked questions
How much tile adhesive per m²?
Typically 2–7 kg/m² depending on the notch size, tile and surface: about 3 kg/m² with a 6 mm (¼ × ¼ in) notch and about 7 kg/m² with a 12 mm (½ × ½ in) notch. Back-buttering large tiles adds about 1.5 kg/m².
Which trowel notch should I use?
Roughly: mosaics 4 mm, tiles up to 300 mm (12 in) 6 mm (¼ × ¼ in), tiles up to 450 mm (18 in) 8–10 mm (¼ × ⅜ in), larger tiles 12 mm (½ × ½ in) with back-buttering. The tile and adhesive makers' guidance comes first.
How much cement and sand do I need for tile flooring?
For a 25 mm (1 in) bed of 1 : 4 mortar with 10 % extra and 4.4 kg/m² of cement slurry, about 15 kg of cement and 0.03 m³ (just over 1 ft³) of sand per m² — roughly one 50 kg bag of cement for every 3.3 m². Choose "Cement–sand mortar bed" to work out your own floor.
Do I need to back-butter tiles?
For large tiles, yes: adhesive makers ask for it so the whole tile is bedded. LATICRETE, for example, says to back-butter tiles larger than 200 × 200 mm (8 × 8 in) with its thinset. Enter the extra in the back-buttering box for any tile you back-butter.
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Sources
- LATICRETE 254 Platinum data sheet: coverage per 50 lb bag by trowel, wet density, mixing ratio and back-buttering
- Manufacturer ranges, e.g. Mapei Keraflex: 2–5 kg/m² with common notched trowels
- Tile flooring on a 1.5 in (40 mm) cement–sand bed: dry volume factor 1.33, cement 1,440 kg/m³ — Civil Sir
- CPWD cement consumption for tiles on a 20–25 mm bed of 1:6 mortar (0.200–0.228 bags/m²) — The Constructor
Formulas last reviewed: September 30, 2026 ·How we check our formulas