Mortar & Grout Calculator
Figure cell-fill grout for a CMU wall: enter the number of fully-grouted 8×8×16 blocks and get the grout volume in cubic feet and cubic yards plus a 60 lb bag count — with the yard figure right next to the bags so you can see when the pour is big enough to order ready-mix instead. Every yield here is a planning figure; confirm cell volume against the block producer's data on large pours. Free, no login.
Grouted Cells
Grout Fill
≈0.45 ft³ grout per fully-grouted 8" block; bag yield ≈0.6 ft³ — planning figures; confirm against the spec. For ready-mix grout, order by yd³.
Mortar & Grout Calculator — Material Order Sheet
Prepared with NORDIX — nordixhq.com/tools/mortar-grout-calculator
| Fully-grouted blocks: 100 | Grout volume: 45 ft³ (1.667 yd³) |
| Material | Qty | Unit | Notes |
|---|---|---|---|
| Grout mix | 75 | 60 lb bags | bag yield ≈0.6 ft³ |
| Ready-mix grout (alternative) | 1.667 | yd³ | order by yd³ at volume |
Method: ≈0.45 ft³ grout per fully-grouted 8" block (2 cells, 8×8×16); 60 lb bag yield ≈0.6 ft³. Empirical planning figures — confirm cell volume and grout spec against the project documents before ordering.
How this calculator works
Cell-fill volume is carried at a planning figure of 0.45 ft³ of grout per fully-grouted 8" block (both cells filled), with bags at a manufacturer-typical 60 lb yield:
grout (ft³) = blocks × 0.45 · yd³ = ft³ ÷ 27 · bags = ⌈ft³ ÷ 0.6⌉
Both constants are empirical, not exact fact: actual cell volume moves with the producer’s web and face-shell thickness, and bag yield with the mix. For partial grouting, count grouted cells and divide by two — 100 grouted cells (vertical bars at spaced cells) enters as 50 blocks — and figure bond-beam courses as fully grouted for their full length. Despite the tool’s name, this covers cell-fill grout only: bed-joint mortar for laying the units lives in the block calculator (≈3 bags per 100 block) and the brick calculator (≈7 bags per 1,000 brick). Grout (ASTM C476) is intentionally fluid so it flows around rebar — regular concrete is not a substitute.
Worked example
A wall with 100 fully-grouted blocks — say vertical bars at every other cell over 200 blocks of wall:
- Volume: 100 × 0.45 = 45 ft³.
- Yards: 45 ÷ 27 = 1.667 yd³.
- Bags: 45 ÷ 0.6 = 75 bags (60 lb) — which is exactly the scale where pump-ready grout by the yard beats mixing bags on labor alone.
Enter 100 blocks above to reproduce it, then print the order sheet.
Reference: grout per fully-grouted block count (planning figures)
Computed from the same ≈0.45 ft³/block and ≈0.6 ft³/bag planning yields the calculator uses. Past roughly a yard (~60 blocks), price ready-mix.
| Fully-grouted blocks | Grout (ft³) | Grout (yd³) | 60 lb bags |
|---|---|---|---|
| 25 | 11.25 | 0.417 | 25 |
| 50 | 22.5 | 0.833 | 50 |
| 100 | 45 | 1.667 | 100 |
| 200 | 90 | 3.333 | 200 |
| 500 | 225 | 8.333 | 500 |
Frequently asked questions
How much grout does it take to fill a concrete block?
This calculator figures 0.45 cubic feet of grout per fully grouted standard 8x8x16 block — both cells filled. That works out to about 60 fully grouted blocks per cubic yard. Actual cell volume varies with the block producer's web and face-shell thickness, so treat it as an estimating figure and check the producer's data on large pours.
How many bags of grout per block?
A 60 lb bag of grout mix yields about 0.6 cubic feet, so a fully grouted block takes about three-quarters of a bag — three bags fills four blocks. The calculator rounds the bag count up to whole bags.
When should I order ready-mix grout instead of mixing bags?
Once the pour passes roughly a yard — about 60 fully grouted blocks, which is 45 bags — bag mixing stops making sense on labor alone. That is why the calculator shows cubic yards next to the bag count: use bags for small cell-fill and bond-beam patches, and order pump-ready grout by the yard for full walls.
How do I count blocks when only some cells are grouted?
The input expects fully grouted blocks, meaning both cells filled. For partial grouting, count grouted cells and divide by two — 100 grouted cells (say, vertical bars at spaced cells) enters as 50 blocks. Bond beams run horizontally, so figure those courses as fully grouted for their full length and add them in.
What is the difference between mortar, grout, and concrete?
Mortar (ASTM C270) beds the units and is stiff enough to hold a joint. Grout (ASTM C476) fills the cells and is intentionally fluid — placed at a high slump so it flows around rebar and fills the webs without voids. Regular concrete is not a substitute for either: coarse aggregate hangs up in the cells and a low-slump mix leaves voids around the steel.
Does this calculator figure bed-joint mortar too?
No — despite the name, this tool covers cell-fill grout only. Mortar for laying the units is figured in the block calculator (about three 70 lb bags per 100 block) and the brick calculator (about seven bags per 1,000 brick).
Method: ≈0.45 ft³ of grout per fully-grouted nominal 8×8×16 block (two cells) and a 60 lb bag yield of ≈0.6 ft³ — both empirical planning figures (two-cell 8×8×16 grout volume rule of thumb (≈0.45 ft³); manufacturer-typical bag yield). Actual cell volume varies by block producer, and grout for reinforced masonry is specified by ASTM C476 with placement governed by the project spec (slump, lift height, consolidation) — confirm quantities and the grout spec against the project documents before ordering. Bed-joint mortar (ASTM C270) is not included here.
Pair with the Block / CMU Calculator for the block count and bed-joint mortar, the Brick Calculator for veneer, or the Construction Calculator for concrete volumes and conversions.