Cinder Block Fence Calculator — Perimeter Wall Estimator
Plan a cinder-block perimeter fence. Estimates blocks, mortar, and pilaster pier counts for property line walls, privacy screens, and security enclosures.
Enter Dimensions
Recommended: 10% for standard projects
Results
Blocks Needed
199blocks
Mortar Bags
7bags
60 lb bags · 1 bag per 30 blocks (NCMA)
Wall Area
160sq ft
Blocks per Sq Ft
1.125blocks/sq ft
BIA standard for 8×16 face
Editorial Standards
Each calculator is reviewed for formula accuracy, unit consistency, and alignment with current U.S. building practices before publication. We verify outputs against published engineering references and real-world project data. Learn more about our methodology.
A cinder-block perimeter fence — sometimes called a screen wall or privacy wall — provides longer service life, better wind resistance, and superior sound dampening compared to wood fencing. Builders typically run them at 6 ft tall along property lines, with intermediate pilasters and either a precast or brick cap on top.
Use this calculator to estimate the field blocks for a straight fence run. Add pilasters and cap units separately. Total ≈ field blocks + (pilaster blocks × pilaster count) + cap units.
How to Estimate a Cinder-Block Fence
Field block count uses the same Length × Height × 1.125 × waste factor formula as any CMU wall. The fence-specific adds are pilasters and cap units.
Pilaster & Cap Allowances
- Pilasters: add 4–6 blocks per pilaster (depends on fence height). Plan a pilaster every 10–15 ft and at every corner.
- Cap units: brick rowlock caps require ≈ 3.5 bricks per linear foot. Precast 16″ concrete caps require 0.75 units per linear foot (one per block course).
- Gate openings: subtract opening area × 1.125 from total block count. Add jamb blocks at each side of the opening.
Frequently Asked Questions
Can I build a cinder-block fence without pilasters?
Short walls under 4 ft can run without pilasters, but anything taller — especially on a property line exposed to wind — needs intermediate pilasters every 10–15 ft for lateral stability.
How deep should the footing be for a cinder-block fence?
A continuous strip footing 12–16 inches wide and 12 inches deep (or below local frost line, whichever is greater) is typical for 6 ft block fences. Reinforce with two #4 longitudinal bars.
Do I need rebar in every core of a fence wall?
No — vertical #4 rebar at 32–48 inch on-center spacing is sufficient for most 6 ft block fence walls. Cores around rebar must be grouted solid; the rest can be left hollow.
How many blocks per 100 linear feet of 6 ft fence?
100 ft × 6 ft = 600 sq ft × 1.125 = 675 blocks before waste. With 10% waste for cuts and pilasters, plan on ordering 742 blocks plus extra for pier caps.
Can I cap a cinder-block fence with brick or stone?
Yes — a brick rowlock cap or precast concrete cap is standard. Allow ~3.5 cap units per linear foot for brick caps, or one 16-inch precast cap per block course.
Looking for the general calculator?
Estimate cinder blocks and mortar bags for any CMU wall. Supports 8-inch and 12-inch blocks with adjustable waste percentage and automatic pallet estimation.
Open the Cinder Block Calculator: Blocks & Mortar →