Quikrete Cement Calculator

Brick and block walls are held together by mortar — the workable paste of cement, sand, and water that hardens into the glue between units. Running out of mortar mid-wall is a miserable experience: the partially built courses start setting, the rhythm breaks, and the color of the new batch may never quite match. Estimating mortar before you start is as important as counting the bricks themselves. The Quikrete Cement Calculator estimates QUIKRETE mortar mix for masonry walls. Select your wall type — brick or concrete block — enter the wall’s length and height, and it reports the wall area, the mortar volume needed, the number of 60-lb and 80-lb bags, the water required, and an estimated cost. This tool is for DIY masons building garden walls, barbecue enclosures, and small block structures, as well as homeowners budgeting a project before hiring a mason. It is also useful for students and apprentices learning how mortar quantities relate to wall dimensions. In this guide, you will learn how mortar estimation works, how to use the calculator step by step, and what the numbers look like in two fully worked examples. You will also learn the joint-volume math behind the figures, the factors that affect your estimate, and practical tips for mixing and laying mortar.

What Is Mortar Estimation?

Mortar estimation converts a wall’s dimensions into the volume of mortar needed to bed and joint its units. Every brick or block sits in mortar: a bed joint underneath, head joints on the sides, and the joints are typically 3/8 inch thick. All those thin layers add up — mortar is roughly 20 percent of a single-wythe brick wall’s volume. The estimation has two steps. First, compute the wall area: length × height in feet gives square feet. Second, multiply by a mortar factor — the cubic feet of mortar per square foot of wall. For a standard single-wythe brick wall the factor is about 0.067, and for a concrete block wall about 0.033, because blocks are larger and have fewer joints per square foot. Bag counts come from mortar yield: a 60-lb bag of QUIKRETE mortar mix produces about 0.45 cubic feet of workable mortar, and an 80-lb bag about 0.60 cubic feet. A concrete illustration: a brick wall 20 feet long and 8 feet high is 160 square feet, needing 160 × 0.067 = 10.72 cubic feet of mortar — that is 24 sixty-pound bags, or 18 eighty-pound bags, plus about 14.4 gallons of water.

Why Accurate Mortar Estimation Matters

Mortar has a working window. Once mixed, it stays workable for roughly 1 to 2 hours; after that it stiffens and must be discarded, not re-wetted. If you underestimate and must mix an emergency batch, the interruption shows in the wall — joints laid with fresh mortar against partially set courses can differ in color and bond. Having the full quantity on site keeps the work continuous and the wall uniform. Overbuying mortar is less disastrous than running short, but it still wastes money and effort. Bags are heavy, and while unopened bags keep, opened ones do not. A good estimate lets you buy the right count plus a small cushion, instead of guessing high “just in case” and ending up with a pallet of leftovers. For budgeting, mortar is a meaningful line item that beginners often forget entirely — they count bricks and skip the glue. On the 160-square-foot example, 24 bags at $7.50 is $180, a cost that belongs in the project budget from day one. The calculator puts it there automatically.

How to Use the Quikrete Cement Calculator

Follow these steps:

1. Step 1: Select the wall type. Choose “Brick Wall” or “Concrete Block Wall” from the dropdown. Brick walls need more mortar per square foot because of their many joints.
2. Step 2: Enter the wall length. Type the wall’s length in feet into the “Wall Length (feet)” field, for example 20.
3. Step 3: Enter the wall height. Type the wall’s height in feet into the “Wall Height (feet)” field, for example 8.
4. Step 4: Click Calculate. The calculator shows wall area, mortar volume, 60-lb and 80-lb bag counts, water needed, and estimated cost. Click Reset to clear the form and estimate another wall.

Worked Example 1: A Brick Wall 20 × 8 ft

You are building a single-wythe brick garden wall 20 feet long and 8 feet high. Step 1 — Wall area. 20 × 8 = 160.0 square feet. Step 2 — Mortar volume. 160 × 0.067 = 10.72 cubic feet. Step 3 — 60-lb bags. 10.72 / 0.45 = 23.8, rounded up to 24 bags. Step 4 — 80-lb bags. 10.72 / 0.60 = 17.9, rounded up to 18 bags. Step 5 — Water. 24 × 0.6 = 14.4 gallons. Step 6 — Estimated cost. 24 × $7.50 = $180.00. The final result: 24 sixty-pound bags of mortar mix and about 14.4 gallons of water will lay the 160-square-foot brick wall, costing roughly $180.

Worked Example 2: A Block Wall 30 × 8 ft

You are building a concrete block wall 30 feet long and 8 feet high. Step 1 — Wall area. 30 × 8 = 240.0 square feet. Step 2 — Mortar volume. 240 × 0.033 = 7.92 cubic feet. Step 3 — 60-lb bags. 7.92 / 0.45 = 17.6, rounded up to 18 bags. Step 4 — 80-lb bags. 7.92 / 0.60 = 13.2, rounded up to 14 bags. Step 5 — Water. 18 × 0.6 = 10.8 gallons. Step 6 — Estimated cost. 18 × $7.50 = $135.00. The final result: despite being 50 percent larger in area, the block wall needs less mortar than the brick wall — 18 bags costing about $135 — because blocks have far fewer joints.

Understanding the Mortar Factor Math

The mortar factor — 0.067 for brick, 0.033 for block — is the heart of the calculator. It represents the cubic feet of mortar in one square foot of finished wall, derived from standard unit sizes and 3/8-inch joints. A single-wythe brick wall is 4 inches thick, so each square foot contains 1/3 cubic foot of wall; about 20 percent of that is mortar, giving 0.067. Block walls use larger 8×8×16-inch units with fewer joints, roughly halving the factor. The yield conversion works exactly like concrete: a 60-lb bag of mortar mix makes about 0.45 cubic feet, an 80-lb bag about 0.60. Dividing the required volume by the yield and rounding up gives whole bags. The water rule of thumb — about 0.6 gallons per 60-lb bag — produces the firm, workable consistency masons want; mortar should hold its shape on the trowel, not slump off it. These are planning estimates, not laboratory figures. Real joints vary with the mason’s hand, and the calculator’s job is to get you the right number of bags to buy — within one bag — not to predict the wall to the ounce.

Key Factors That Affect Your Estimate

Joint thickness is the biggest variable. The factors assume standard 3/8-inch joints; thicker joints from uneven units or a heavy hand can raise mortar use noticeably. Beginners typically use more mortar than experienced masons, so adding 10 percent to the bag count is prudent for a first wall. Wall configuration matters too. The factors assume a single-wythe wall — one unit thick. A double-wythe wall (two bricks thick) needs roughly double the mortar, and piers, corners, and openings add joints beyond the flat-wall math. For complex walls, estimate the flat area first, then add 10 to 15 percent. Waste is unavoidable: mortar drops, boards need scraping, and mixed batches stiffen before use. The round-up in the bag calculation covers small waste, but on large walls an extra bag or two beyond the count is cheap insurance.

Common Mortar Estimating Mistakes

The biggest mistake is confusing mortar with concrete. Mortar contains no coarse aggregate and is estimated by joint volume, not slab volume — applying concrete math to a brick wall produces absurd over-orders. Use the mortar factors (0.02 for brick, 0.01 for block), not concrete yields. Second, joint thickness changes everything. The standard factors assume roughly 3/8-inch joints; thicker joints or irregular stone can double mortar consumption. For stone veneer or rustic brick with wide joints, increase the estimate by 25 to 50 percent. Third, opened bags go stale. Mortar mix absorbs moisture from the air, and a bag opened last season may never set properly. Buy fresh bags for the project, store them sealed and dry, and never stretch an estimate by using questionable leftover mix on structural joints.

Tips for Mixing and Laying Mortar

1. Buy 10 percent more bags than calculated if this is your first masonry project.
2. Mix small batches you can use within 1 to 2 hours — never re-temper stiffened mortar with water.
3. Add water gradually; proper mortar holds its shape on an overturned trowel.
4. Keep bricks and blocks dry before laying; wet units weaken the bond.
5. Tool the joints when the mortar is thumbprint-hard for a neat, weatherproof finish.
6. In hot or windy weather, work in the shade and mist the wall lightly to slow drying.
7. Cover unfinished walls with plastic if rain threatens — washed-out joints are permanent.
8. Clean tools immediately; hardened mortar ruins trowels and mixers.
9. Store unopened bags dry and off the ground; one damp bag can spoil a batch.

Frequently Asked Questions

1. What does the Quikrete Cement Calculator estimate? It estimates QUIKRETE mortar mix for brick and concrete block walls from the wall’s length and height. You get wall area, mortar volume, 60-lb and 80-lb bag counts, water needed, and estimated cost.

2. What is the difference between mortar mix and concrete mix? Mortar mix contains cement and sand but no gravel, giving it the sticky, workable texture needed to bed bricks and blocks. Concrete mix contains gravel for strength in slabs and footings. Use mortar mix for masonry walls.

3. How many bags of mortar per 100 square feet? Roughly 15 sixty-pound bags for a brick wall and 8 for a block wall at standard joints. The calculator computes the exact figure for your dimensions — 24 bags for the 160-square-foot brick example.

4. Why do brick walls need more mortar than block walls? Bricks are small, so a square foot of brick wall contains many more joints than a square foot of block wall. More joints mean more mortar — about twice as much per square foot.

5. How thick should mortar joints be? Three-eighths of an inch is the standard for both brick and block. Consistent joints are the hallmark of good masonry — they affect strength, appearance, and the accuracy of any estimate.

6. How much water goes into mortar? About 0.6 gallons per 60-lb bag as a starting point, adjusted for conditions. The right mix is workable but firm: it should spread easily yet hold its shape on the trowel.

7. Can I re-wet mortar that has stiffened? No. Adding water to stiffened mortar — called re-tempering — weakens it permanently. Discard any batch you cannot use within its working time and mix fresh.

8. How long does mortar take to set? It stiffens within a couple of hours and gains strength over about 28 days, like concrete. Walls should be protected from rain, freezing, and heavy loading during the first days.

9. Do I need a concrete footing under a brick wall? Yes for any structural or tall wall — masonry needs a proper footing below the frost line to prevent settling and cracking. Small garden walls may sit on a compacted gravel base; check local codes.

10. What is a wythe? A wythe is one vertical layer of masonry units. A single-wythe wall is one brick thick; a double-wythe wall is two bricks thick and needs about twice the mortar. The calculator assumes single-wythe.

11. How accurate is the bag estimate? Within about one bag for careful work at standard joints. Beginners should add 10 percent because thicker joints and waste raise real consumption above the theoretical figure.

12. Can I use mortar mix for a concrete slab? No. Mortar lacks the gravel aggregate that gives concrete its compressive strength. Slabs, footings, and posts need concrete mix; mortar is only for bedding masonry units.

13. What are Type N and Type S mortar? They are strength grades: Type N suits most above-grade walls; Type S is stronger for below-grade and structural work. QUIKRETE bags are labeled by type — match the type to your project.

14. How do I estimate a wall with a door or window opening? Calculate the full wall area, subtract the opening area, and run the remainder through the calculator. Openings also add joint work around their edges, so keep the waste cushion.

15. How should I store leftover mortar bags? Sealed, dry, and off the ground — moisture ruins them quickly. Properly stored bags last several months; a bag that has hardened lumps in it should be discarded.

CONCLUSION

The Quikrete Cement Calculator answers the mason’s essential question — how much mortar? — from just three inputs: wall type, length, and height. Out come the volume, bag counts, water, and cost, ready for the shopping list. The single most important takeaway: estimate before you build, buy a small cushion, and mix only what you can lay within the working window. Mortar waits for no one, but with the right bags on site, your wall goes up course by steady course without interruption.