Outdoor Kitchen Block Calculator
Building an outdoor kitchen frame out of concrete block starts with knowing how many blocks you actually need. Enter your layout length, wall height, and appliance openings, and this calculator works out block count, mortar bags, and cost.
Total area of doors, windows or other openings to subtract.
Covers cuts, breakage and layout waste. 5–10% is normal.
Everything is calculated in your browser. Nothing you type is sent anywhere or stored.
Ordering tips
—
Coverage & waste
Material profile
Multiply the total run length of the block wall by its height to get gross face area, then subtract the square footage of appliance and door openings to get net area. Add a waste percentage for cut blocks and breakage, then divide by one block’s face area, 0.89 sq ft for a standard 8x8x16 in CMU, and round up to a whole block since block isn’t sold in fractions.
CMU Block Sizes for Outdoor Kitchens
Block width (the third dimension, not shown in face area) affects load capacity and how much appliance/countertop weight the wall can carry. Face area stays 0.89 sq ft (8×16 in nominal face) across standard CMU widths.
| Block Size | Face Area | Best Use |
|---|---|---|
| 8x8x16 in CMU | 0.89 sq ft | Standard load-bearing outdoor kitchen frame |
| 6x8x16 in CMU | 0.89 sq ft | Lighter partition or non-load-bearing walls |
| 12x8x16 in CMU | 0.89 sq ft | Heavier islands supporting large grills or stone counters |
CMU block coverage by size
| Type | Coverage / unit | Size | Best for |
|---|---|---|---|
| 8x8x16 in CMU block | 0.89 sq ft | 8 x 8 x 16 in | Standard outdoor kitchen frame |
| 6x8x16 in CMU block | 0.89 sq ft | 6 x 8 x 16 in | Lighter partition walls |
How to calculate how many CMU blocks you need
- Lay out the frame total run length of block wall in the outdoor kitchen, including any returns or islands.
- Multiply by height the finished wall height, from the footing or slab up to the top course.
- Subtract openings square footage of appliance cutouts, doors, and drawer openings.
- Add waste 8% is typical to cover cut blocks at corners and openings.
- Divide by block face area 0.89 sq ft for a standard 8x8x16 in block, and round up to a whole block.
Worked example
Here’s a 16 ft outdoor kitchen frame at 3.5 ft finished height, with 8 sq ft of appliance openings, using standard 8x8x16 in CMU and 8% waste.
- Frame footprint (16 ft x 3.5 ft)56.0 sq ft gross
- Appliance/door openings8 sq ft
- Net wall area48.0 sq ft
- Waste added8%
- Block selected8x8x16 in CMU (0.89 sq ft face)
- Blocks needed59 blocks
- Mortar2 bags
- Block cost (59 x $3.25)$191.75
- Mortar cost (2 x $12)$24
- Total estimated cost$215.75
CMU Block Sizes for Outdoor Kitchens
| Block Size | Face Area | Best Use |
|---|---|---|
| 8x8x16 in CMU | 0.89 sq ft | Standard load-bearing outdoor kitchen frame |
| 6x8x16 in CMU | 0.89 sq ft | Lighter partition or non-load-bearing walls |
Ordering Block and Mortar for an Outdoor Kitchen
Outdoor kitchen frames carry real weight: countertops, grills, refrigerators, and stone or stucco veneer. Order block and mortar with some margin, and plan reinforcement before the first course goes down.
- Order by the palletblock yards typically sell CMU in units of 90-108 blocks per pallet – round up to avoid a partial-pallet delivery fee.
- Budget mortar by the bagone 80 lb bag of Type S mortar mix typically sets around 25-30 standard 8x8x16 in blocks with 3/8 in joints.
- Measure appliance cutouts before orderingrough openings for grills, doors, and drawers reduce block count – measure the actual units, not catalog specs.
- Add rebar and grout separatelyvertical reinforcement at corners and opening jambs isn’t part of the block/mortar count and should be priced on its own.
Common mistakes
- Not subtracting appliance openingsgrill, fridge, and drawer cutouts reduce block count and should always be measured and deducted, like the calculator does.
- Skipping reinforcementoutdoor kitchen frames carry countertop and appliance weight and need rebar and grouted cores at corners and openings per local code.
- Forgetting the finish layerveneer stone, stucco, or tile over the block has its own separate material and mortar cost.
- Wrong block for the loada 6 in block might save money but isn’t rated for the same load as an 8 in block under a heavy stone countertop.
What this calculator assumes
Adjust your result if your project differs from these.
- Wall is a single-wythe CMU structure laid in standard running bond.
- Mortar joints are a standard 3/8 in, typical for CMU coursing.
- Height entered is the finished wall height, including the cap course.
- Openings are the combined square footage of appliance cutouts and doors.
- Estimate covers block and mortar only, not veneer, rebar, grout fill, or countertops.
Common questions
How many blocks do I need for a 16 ft outdoor kitchen frame?
At 3.5 ft height with 8 sq ft of appliance openings and 8% waste, a 16 ft run needs 59 standard 8x8x16 in CMU blocks.
Should I use 6 in or 8 in block?
8 in block is the standard choice for load-bearing outdoor kitchen frames carrying countertops and appliances. 6 in block works for lighter, non-load partitions.
How much mortar do I need per block?
Roughly 25-30 standard 8x8x16 in blocks per 80 lb bag of Type S mortar mix, depending on joint thickness and mason technique.
Do I need rebar in an outdoor kitchen block wall?
Most codes require vertical reinforcement (rebar and grouted cores) at corners and at appliance opening jambs for structural block walls. Check your local code.
Is a stone or stucco finish included in this estimate?
No. This calculator covers the CMU block frame and mortar only. Veneer stone, stucco, or tile finishes are priced and ordered separately.
Embed this calculator
Related calculators
Outdoor Kitchen Block Calculator Estimate
—
materialcalculate.com/tools/outdoor-kitchen-block-calculator/
Project
| Wall size | — |
| Openings deducted | — |
| Net area | — |
| Material | — |
| Waste allowance | — |
Shopping list
| Units needed | — |
| Mortar / mix | — |
| Estimated total cost | — |
Notes
Estimate generated by materialcalculate.com. Confirm quantities with your supplier before ordering.