Retaining Wall Block Count

Blocks per course is the wall length over block width; the number of courses is wall height over block height. Multiply the two for the total.

Your numbers

Wall length(m)Wall height(m)Block width (cm)(cm)Block height (cm)(cm)

Blocks needed

100

Courses

Blocks per course

What it means

You need 100 blocks — 5 course(s) × 20 per course.

Formula

Blocks needed = ⌈Wall length÷(Block width (cm)÷100)⌉ × ⌈Wall height÷(Block height (cm)÷100)⌉

A buried base course or a capping block often uses a different size — count those separately.

What to enter

Input	Default	Accepted range
Wall length (m)	8	0.5 and up
Wall height (m)	1	0.1 and up
Block width (cm) (cm)	40	5 and up
Block height (cm) (cm)	20	5 and up

Step by step

FormulaBlocks needed = ⌈Wall length÷(Block width (cm)÷100)⌉ × ⌈Wall height÷(Block height (cm)÷100)⌉

With the default numbersBlocks needed = ⌈8÷(40÷100)⌉ × ⌈1÷(20÷100)⌉

AnswerBlocks needed = 100

Quick reference table

Results when only Wall length (m) changes and everything else stays put.

Wall length (m)	Blocks needed	Courses	Blocks per course
4	50	5	10
6	75	5	15
8	100	5	20
12	150	5	30
16	200	5	40

What each result means

Result	At default values
Blocks neededCourses times blocks per course — the total block count.	100
Courses	5
Blocks per courseWall length over block width — how many blocks make up one course.	20

Common mistakes

A buried base course or a capping block often uses a different size — count those separately.

Glossary

Blocks needed: Courses times blocks per course — the total block count.
Blocks per course: Wall length over block width — how many blocks make up one course.

Frequently asked questions

QHow is Retaining Wall Block Count calculated?

Blocks needed = ⌈Wall length÷(Block width (cm)÷100)⌉ × ⌈Wall height÷(Block height (cm)÷100)⌉ — Blocks per course is the wall length over block width; the number of courses is wall height over block height. Multiply the two for the total.

QCan you walk through an example?

With Wall length 8m, Wall height 1m, Block width (cm) 40cm, Block height (cm) 20cm, the answer is Blocks needed 100.

QWhat do I need to enter?

Enter Wall length, Wall height, Block width (cm), Block height (cm). The result recalculates as you type, and an empty box counts as zero.

QHow much does the answer move if I change a number?

Changing only Wall length (m) moves the answer to Wall length (m) 4 → Blocks needed 50 and Wall length (m) 16 → Blocks needed 200. The table below lays out five steps.

QHow are the numbers rounded?

Money is shown to the nearest whole unit, percentages to one decimal place and everything else to two. What you see is rounded; the calculation itself carries the unrounded value forward.

QAnything to watch out for?

A buried base course or a capping block often uses a different size — count those separately.

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Keep your length units consistent across inputs — mixing centimetres and metres throws results far off.