Concrete Block Fill Calculator — Concrete-Depot.com

Calculate the exact volume of grout or concrete fill needed for your block wall, including bag counts, rebar, and waste factors.

Select Section

Wall Length (ft) Total linear feet

Wall Height (ft) Total height

Block Thickness (in)

Block Width (in) Nominal

Block Height (in) Nominal

Mortar Joint (in) Standard 3/8"

Number of Webs

Waste Factor (%)

Rebar Spacing (in) Optional: e.g., 24"

Cost per cu yd ($)

3D Block Shape

How to use this tool

Enter the total length and height of your block wall.
Select or enter the dimensions of your concrete blocks.
Adjust the mortar joint thickness (3/8" or 10mm is standard).
Choose the number of webs (hollow cores) in your block type.
Optionally add rebar spacing and material cost for a full estimate.
Results update instantly. Download the PDF for your records.

Formula used

Blocks Needed: (Wall Length × 12 / Effective Width) × (Wall Height × 12 / Effective Height)

Effective Dimension: Nominal Block Dimension + Mortar Joint

Core Volume: (Block Width - 2×Shell - Webs×Web Thickness) × (Block Height - 2×Shell) × Block Thickness × Number of Cores

Bag Counts: Total Cu Ft ÷ 0.45 (for 60lb) or 0.60 (for 80lb)

Waste Factor: Total Volume × (1 + Waste % / 100)

Concrete Curing Time Chart

Concrete gains strength over time. Here is the standard curing timeline for normal Portland cement concrete at 70°F (21°C).

Stage	Time	Strength	What You Can Do
Initial Set	24 – 48 hours	~500 psi	Walk on it, remove forms carefully
Partial Cure	7 days	~3,000 psi (70%)	Drive cars on it, light construction
Full Cure	28 days	~4,000 psi (100%)	Full design strength, heavy loads
Long Term	Months/Years	Continues slowly	Concrete actually gets harder over years

Note: Cold weather significantly slows curing. Below 50°F, double the initial set times. Above 90°F, concrete cures faster but may crack without proper moisture retention.