Updated Construction & Masonry Tool

Block Calculator

Estimate concrete blocks, mortar, rebar and grout for one or multiple walls. Enter dimensions, openings, block size, joints, fill and cost to get total quantities and cost breakdown.

Multiple Walls Mortar & Rebar Grout Fill Cost Estimation

Calculate Concrete Blocks, Mortar, Rebar & Grout

Use this all-in-one Block Calculator to estimate the total number of concrete blocks, mortar volume, rebar length, grout fill and overall cost for your masonry project. Supports multiple wall entries, openings and different block standards.

Block & Material Settings

Length of one block
Height of one block
Wall thickness

Walls & Openings

Add walls below. Each wall can have its own dimensions, openings, rebar spacing and grout fill percentage.

Wall 1

inches
inches
0–100 %

Block Calculator – Comprehensive Guide to Concrete Blockwork Estimation

This Block Calculator helps builders, contractors and DIY users estimate materials for block walls — including concrete blocks, mortar, rebar and grout fill — with detailed totals and cost analysis.

1. Supported Block Sizes and Presets

  • 8 × 8 × 16 in (203 × 203 × 406 mm) – Standard CMU block for load-bearing walls.
  • 6 × 8 × 16 in (152 × 203 × 406 mm) – Lighter partition block for non-load walls.
  • 390 × 190 × 190 mm – Metric CMU common in UAE, Pakistan and Asia.

You can select a preset or enter custom block dimensions to match your project.

2. Materials Included in the Calculation

  • Concrete blocks: Based on net wall area after subtracting openings.
  • Mortar volume: Calculated from block bed and head joints with a 1 : 4 mix.
  • Rebar: Vertical & horizontal steel reinforcement using your spacing inputs.
  • Grout fill: Volume of voids filled with grout (0–100 %).
  • Cost estimate: Optional block cost multiplied by total blocks plus materials.

3. How to Use the Block Calculator

  1. Choose your units (feet or meters) and block preset size.
  2. Enter block dimensions, mortar joint thickness, and wastage percentage.
  3. Add each wall with length, height, openings, rebar spacing and grout fill percentage.
  4. Optionally enter a cost per block and currency symbol.
  5. Click the calculate button to see total blocks, mortar volume, rebar, grout and cost.

4. Practical Guidelines

  • Use realistic rebar spacing (e.g., 24 in horizontal and vertical for standard walls).
  • Apply a 5–10 % wastage allowance for blocks and mortar.
  • Adjust grout fill percentage depending on wall type — 100 % for structural, 30–50 % for partitions.

5. Related Tools

Block Calculator FAQs

Frequently Asked Questions

Quick answers about concrete block calculations, rebar spacing, mortar and grout estimation.

Yes. Each wall has independent dimensions, openings and rebar spacing. The calculator combines all wall totals for a complete material estimate.

You can set a fill percentage from 0–100 %. Structural walls often use 100 %, while partition walls may be partially filled to save material.

The default mortar mix is 1 : 4 (cement : sand), but you can adjust it to 1 : 5 or other ratios depending on your project specifications.

Yes, enter custom block dimensions or choose a preset. For hollow blocks, use grout fill percentage to account for void volume.

Yes, it computes total rebar length and converts it to approximate weight using density of steel (7850 kg/m³). You can include a cost per meter if desired in a later version.

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