How many bags of mortar per 100 block?
Laying 100 standard 8×8×16 blocks takes about 7.7 bags of 80 lb mortar mix, at Quikrete’s figure of up to 13 blocks per bag. With 15% extra, buy 9 bags.
How to work it out
- 100 blocks ÷ 13 per 80 lb bag = 7.7 bags
- + 15% = 9 bags
A hundred blocks is about 89 square feet of wall — a small garden wall, a shed foundation, or a day’s work for one mason. It is a handy unit for scaling mortar to any block job.
Adjust for your project
More options: Extra
- Units per bag (Quikrete)
- Up to 13 blocks per 80 lb bag
- Cross-check
- CMHA: about 7.2 bags of 80 lb at 16 blocks per bag with face-shell bedding
- Weight of the bags
- 720 lb
- “Up to” on the bag assumes neat, consistent joints. Beginners, wide joints and full mortar beds under block use more — that is what the extra is for.
Bags of 80 lb mortar by block count (15% extra)
| How many units | Mortar mix bags | Weight of the bags |
|---|---|---|
| 50 | 5 bags | 400 lb |
| 100 | 9 bags | 720 lb |
| 200 | 18 bags | 1,440 lb |
| 300 | 27 bags | 2,160 lb |
| 500 | 45 bags | 3,600 lb |
Nine bags, or fewer?
Quikrete’s “up to 13 blocks per 80 lb bag” is a best case with neat, consistent ⅜ in joints. Mortar dropped off the trowel, mortar that stiffens in the tub before you use it, and full bedding under the first course all eat into it. BIA suggests adding 15–25% to mortar estimates; at 15%, 100 blocks need 8.85 bags, so buy 9.
CMHA’s estimating guide is more generous: about 16 blocks per 80 lb bag of preblended mortar when only the face shells are mortared, which is common practice for hollow block. On that basis 100 blocks need 6.25 bags, or about 7.2 with the same extra. The difference is the bedding method — face-shell versus full.
Smaller bags
If 80 lb bags are too heavy to handle comfortably, the older Quikrete table gives 9 blocks per 60 lb bag (about 13 bags for 100 blocks with 15% extra) and 6 per 40 lb bag (about 20). For the blocks themselves, see how many blocks per square foot; for brick, how many bags of mortar per 1000 brick.
Different size? Use the full Mortar Calculator.
What you’ll need
- Mortar hawkBudget price
A flat board with a handle underneath that holds a load of mortar or stucco next to the work.
See options on Amazon (opens in a new tab) - Brick trowelBudget price
Spreads and furrows the mortar bed and butters the ends of each block or brick. A 10–11 in trowel suits most hands.
See options on Amazon (opens in a new tab) - Mortar and concrete mixing tubBudget price
A wide, shallow tub for one or two bags at a time — easier to clean and to pull a hoe through than a wheelbarrow.
See options on Amazon (opens in a new tab)
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Frequently asked questions
How many 60 lb bags of mortar per 100 block?
13 bags of 60 lb with 15% extra, at 9 blocks per bag.
How much mortar for 200 blocks?
18 bags of 80 lb with 15% extra.
How many bags of mortar per block?
About 1/13 of an 80 lb bag per block (roughly 6 lb of mix), by Quikrete’s figure.
Other common sizes
- How many bags of mortar per 1000 brick — 32 bags of 80 lb mortar mix (27 before the 15% extra)
Sources
- Quikrete Mortar Mix (No. 1102) data sheet (opens in a new tab) — Each 80 lb bag lays up to 37 standard bricks or 13 standard 8×8×16 blocks.
- Quikrete Mortar Mix data sheet (2007 edition, Table 1) (opens in a new tab) — 80 lb: 12 blocks or 37 brick; 60 lb: 9 blocks or 28 brick; 40 lb: 6 blocks or 19 brick.
- Quikrete Mason Mix (No. 1136, Type S) data sheet (opens in a new tab) — Each 80 lb bag lays up to 37 standard bricks or 13 standard blocks.
- CMHA (formerly NCMA) TEK 04-02A — Estimating concrete masonry materials (opens in a new tab) — Each 8×16 unit covers 8/9 sq ft, so 112.5 units per 100 sq ft (119 with 5% waste); grout per 100 sq ft by unit width and core spacing (Table 3); cores filled per 80 lb grout bag (Table 4); one 80 lb bag of preblended mortar lays about 16 CMU with face-shell bedding (Table 2).
- Brick Industry Association — Technical Note 10, Dimensioning and Estimating Brick Masonry (opens in a new tab) — Table 4: brick per 100 sq ft and mortar per 100 sq ft and per 1,000 brick for modular and non-modular sizes; add at least 5% to brick and 15–25% to mortar for waste.
- Quikrete Portland Cement data sheet (opens in a new tab) — Concrete mix 1 part cement : 2 parts sand : 3 parts gravel by volume; five to six 94 lb bags of cement per cubic yard of concrete; Type S and Type N mortar and ASTM C926 stucco blends.
- Quikrete Mortar Mix — product page (pallet quantities) (opens in a new tab) — 40 lb bags 80 per pallet, 60 lb 56, 80 lb 42.
- Sakrete Mortar Mix Type S — product data sheet (Sika Canada) (opens in a new tab) — A 30 kg (66 lb) bag makes about 0.65 cu ft of fresh mortar; lays about 12 blocks or 33 bricks with 3/8 in joints.