Mortar Calculator
Size the mortar for a brick or block job from real geometry — wall area, unit type and joint thickness — with premix bag counts, a site-mix cement & sand estimate, U.S. pricing, and a downloadable PDF.
Mortar yields vary by mix, joint size and workmanship — follow the bag maker's coverage. Prices use 2024-2025 U.S. figures. For planning purposes only.
| Joint | Units / Bag | Bags | Sand (ton) |
|---|
For your 748 units. Thicker joints use more mortar and more bags.
How to use the mortar calculator
Four quick steps turn your brick or block count into a mortar order — bags of mix, or cement, lime, and sand for a site mix — with joint thickness and waste dialed in, a comparison, and a downloadable PDF.
Enter the units
Type how many bricks or blocks you’re laying, or the wall area if you’d rather work from that.
Set the joint
Choose your mortar joint thickness — the standard is 3/8″, and the mortar scales with it.
Pick mix & waste
Choose premixed bags or a site mix and mortar type, set the waste %, and enter prices.
Read results & save a PDF
Get bags of mortar (or cement, lime, and sand), a cost breakdown, and a material list.
How the mortar estimate is calculated
Mortar follows from how many units you’re laying and how thick the joints are. The calculator starts from your brick or block count, applies the mortar per unit, scales for joint thickness, and adds waste. Here is the exact math.
Worked example — 1,500 modular bricks at a 3/8″ joint
Bags rule: 1,500 ÷ 1000 × 7 = 10.5
Round up: → 11 bags of premixed mortar
Check: 1,500 ÷ ~125 per bag ≈ 12 bags (the two rules bracket the same answer)
≈ 11 bags of 80 lb premixed mortar for 1,500 bricks at a standard joint — add waste and round up.
Mortar estimating charts
Handy lookups for the questions people ask most — bags by brick and block count, how the joint changes it, and which mortar type to use. Figures assume a 3/8-inch joint and premixed 80 lb bags, so confirm your own mix.
| Bricks (modular) | Mortar bags | Rough sand (site mix) |
|---|---|---|
| 250 | 2 bags | ~0.25 ton |
| 500 | 4 bags | ~0.5 ton |
| 1,000 | 7 bags | ~1 ton |
| 1,500 | 11 bags | ~1.5 tons |
| 2,000 | 14 bags | ~2 tons |
| 3,000 | 21 bags | ~3 tons |
About 7 bags of premixed mortar per 1,000 bricks. Sand figures are rough guides only if you’re site-mixing from cement and lime instead of buying premix.
| Blocks (8″ CMU) | Mortar bags |
|---|---|
| 50 | 2 bags |
| 100 | 3 bags |
| 200 | 6 bags |
| 300 | 9 bags |
| 500 | 15 bags |
About 3 bags per 100 standard blocks. Blocks are large, so one bag lays only ~33 of them versus ~125 bricks — don’t reuse a per-brick rule for block.
| Joint thickness | Mortar factor | Notes |
|---|---|---|
| 1/4″ joint | ~0.67× | Tight joints; about a third less mortar |
| 3/8″ joint | 1.0× | The standard baseline |
| 1/2″ joint | ~1.33× | Wider joints; about a third more mortar |
| 5/8″ joint | ~1.67× | Rustic / rough work; lots more mortar |
Mortar scales roughly with the joint, so consistent joints keep both the look and the estimate reliable. Set your joint in the calculator before ordering.
| Type | Strength | Best for |
|---|---|---|
| Type N | Medium | General above-grade walls, veneers, chimneys |
| Type S | High | Below-grade, foundations, structural walls |
| Type M | Highest | Heavy loads, retaining walls, driveways |
| Type O | Low | Interior, non-load-bearing, repointing soft brick |
Most homes use Type N or S. Match the type to the job and code rather than always picking the strongest — an over-hard mortar can damage softer masonry over time.
sets bags/unit
scales mortar
drops & set mix
Mortar isn’t measured by the brick alone — three things move the total, and the calculator handles each.
- Brick vs block — a bag lays ~125 bricks but only ~33 blocks, so the unit type matters.
- Joint thickness — a 1/2″ joint uses about a third more mortar than a 3/8″ one.
- Waste — mortar drops off the trowel and stiffens, so 10–15% is normal to add.
Everything the calculator works out
One unit count gives you a complete mortar order — the bags or raw ingredients, the cost, and a joint comparison.
Key figures every mortar job depends on
Built for any masonry job
From a garden wall to a block foundation, the same calculator scales to the units, the joint, and the mix you’re using.
Laying a garden wall or planter and wants the right number of mortar bags without over- or under-buying.
- Enter your brick count
- Set the joint you’re aiming for
- Mix only what you can lay in an hour
Estimating mortar and materials for a bid and needs bags, ingredients, and cost in one place.
- Pick premix or a site mix
- Choose the right mortar type
- Save the PDF material list for the quote
Building block walls or a foundation and needs mortar figured for large units, not bricks.
- Switch the unit to block
- Use Type S for below grade
- Total bags across every course
7 tips for an accurate mortar order
Small habits keep your mortar count right and your batches workable, whether you buy premix or mix on site.
Mortar calculator FAQ
The bags, sand, joint, and mortar-type questions people ask most before mixing.
Estimate mortar from how many bricks or blocks you’re laying. A common rule is about 7 bags of mortar mix per 1,000 modular bricks, or about 3 bags per 100 standard blocks, at a 3/8-inch joint.
For 1,500 bricks that’s roughly 11 bags. Thicker joints, rougher units, and waste all push the number up, so it’s worth rounding up and keeping a spare bag.
An 80 lb bag of premixed mortar lays roughly 125 modular bricks or about 33 standard 8-inch blocks at a normal 3/8-inch joint.
Blocks are much larger than bricks, so a bag covers far fewer of them. The exact yield depends on the mix brand, the joint thickness, and how much mortar ends up wasted, so treat these as planning figures.
Joint thickness is a major driver of how much mortar you use. The standard is 3/8 inch, and mortar scales roughly in proportion to the joint.
A 1/2-inch joint uses about a third more mortar than a 3/8-inch joint, while a 1/4-inch joint uses about a third less. Keeping joints consistent both looks better and makes your mortar estimate reliable.
Mortar is graded by strength. Type N is a general-purpose mix for most above-grade walls; Type S is stronger for below-grade and structural work; Type M is the strongest, for foundations and heavy loads; and Type O is a soft, low-strength mix for interior, non-load-bearing walls.
Most home projects use Type N or Type S. Match the type to the job and the local code rather than defaulting to the strongest, since an over-strong mortar can actually harm softer masonry.
If you mix mortar on site from Portland cement and lime, you’ll add sand at roughly a 3-to-1 sand-to-cement ratio by volume, which is a lot of sand for a big job.
Many DIY and small jobs instead use premixed mortar in a bag, which already contains the sand — you just add water. The calculator can estimate bags of premix, or cement, lime, and sand for a site mix.
For standard 8 by 8 by 16 inch concrete blocks, plan on about 3 bags of mortar mix per 100 blocks at a 3/8-inch joint, so 200 blocks needs roughly 6 bags.
Blocks use mortar only on their face shells, not a full bed, but their large size still means a bag covers only about 33 of them. Add waste and round up so you don’t stop mid-course.
Add about 10% to 15% for mortar that drops off the trowel, sticks to the mixer and board, or stiffens before it can be used. Mortar is wasted more readily than the units themselves.
Mix only what you can lay in about an hour or two before it starts to set, since re-tempering has limits. It’s normal to lose a meaningful share of each batch, so build that into the order.
No. Mortar begins to set once water is added and should be used within about 90 minutes to two hours, so mix it fresh on the day and only in batches you can lay in that window.
You can re-temper slightly stiffened mortar once by adding a little water, but not after it has begun to harden. Never use mortar that has started to set, since it won’t bond properly.
General Estimating Notice: This calculator estimates mortar bags or raw cement, lime, and sand from your brick or block count, joint thickness, mortar type, waste, and the prices you enter, using standard rules of thumb and typical 2024–2025 U.S. figures. Actual mortar use varies with unit size, joint thickness, bed style, mixing method, and site conditions. Mortar sets quickly and must be mixed fresh and used within its working time. Always confirm quantities and the correct mortar type against product data and local code before ordering. For planning purposes only.