How to Estimate Pavers, Gravel and Garden Walls

Everything here goes on the ground rather than into it, and that changes what the estimate has to get right. You can go back for one more paver. You cannot easily fix a patio that ruts because the bedding was too deep, or a wall that is a course short.

Five tools. If you are pouring the concrete underneath first, that is the other guide.

Pavers: the sand is where patios fail

Two tools, and the second matters more than people expect.

The Paver Calculator gives you the paver count from your area and paver size, with an allowance for cuts.

The Paver Sand Calculator is the one worth reading properly. One cubic yard covers exactly 324 sq ft at one inch — and one inch is the whole answer. A thicker sand bed feels like extra care and is the commonest reason a patio ruts, because sand deeper than about an inch keeps consolidating under load after you have finished. More bedding is not more support.

That is the single most useful thing on this page. It is also counter-intuitive, which is why it gets ignored: every instinct says a deeper bed is a kinder one.

Gravel: get the unit right

The Gravel Calculator reports both cubic yards and tons, deliberately, because suppliers quote one or the other and they are not interchangeable.

Ordering the right number in the wrong unit is a lorry-sized mistake — and it is one you find out about when it is being tipped on your driveway. Check which unit your supplier is quoting before you place the order, then read the matching figure.

Walls: count the course you cannot see

The Retaining Wall Block Calculator counts blocks, courses and caps — including the buried first course, which almost every estimate forgets. That course is what makes the wall work, and leaving it out of the count understates the job by a whole row.

It is an easy row to lose, because it is the one you will never look at again once the job is done. It is also the one holding everything above it in place.

Brick: use your real joint, not a rule of thumb

The Brick Calculator works bricks per square foot from your actual brick and joint size rather than a rule of thumb, because the joint width moves the count by about a seventh.

Rules of thumb assume a joint you may not be using. Measure the brick you have actually bought and the joint you are actually laying, and the count stops being an approximation.

The order to run them in

1. Gravel Calculator — the base goes down first, and it is the biggest delivery.
2. Paver Calculator — the count, with cuts allowed for.
3. Paver Sand Calculator — at one inch, and no more.
4. Retaining Wall Block Calculator — including the buried course.
5. Brick Calculator — with your real joint width.

The short version

• Paver sand at one inch. Deeper bedding is the commonest cause of a rutted patio.
• Confirm whether gravel is quoted in yards or tons before ordering.
• Count the buried first course on a retaining wall.
• Use your real joint width for brick — it moves the count by about a seventh.

Each has a printable carrying its own assumptions, which is the version worth having with you at the merchant's counter.