Pea Gravel vs Crushed Stone

There is exactly one difference that matters between pea gravel and crushed stone, and everything else follows from it: crushed stone is angular and pea gravel is rounded.

Angular stone interlocks. Press it together and the faces wedge against each other into a surface that carries load. Rounded stone cannot do this — the pebbles roll past each other under any pressure. That is why one is a construction material and the other is a decorative surface.

Side by side

Where fines change everything

Crushed stone is not one product. The critical distinction inside the category is whether it contains fines — the stone dust left over from crushing.

• Crusher run (#411, QP, dense-grade) keeps its fines. The dust fills the voids between stones and, once compacted, sets into something close to a soft pavement. This is base material.
• #57 and #8 stone are washed, so the fines are gone. Water passes straight through and the stone never locks up. This is drainage material.

Using the wrong one is the most common mistake in DIY gravel work: washed stone in a driveway base never firms up, and crusher run in a French drain silts the pipe within a couple of years.

Which to use, by job

One genuine safety issue

Never put pea gravel or river rock inside a fire pit. Rounded stone is rounded because water shaped it, and porous water-worn stone can hold moisture inside. Heat it hard enough and that trapped water turns to steam with nowhere to go, which can crack or pop the stone.

Use washed #57 crushed stone in the pit itself. Pea gravel is fine as the surround where people sit — just not in the fire. The fire pit calculator sizes both separately for this reason.

The cost surprise

Most people assume the decorative option is cheaper. It is the opposite: pea gravel costs more per ton than crusher run because it has to be washed and screened to a uniform round size, and it is often hauled further.

Pea gravel also usually needs edging, which crushed stone does not. Add $3.50 to $9.00 per linear foot around the whole perimeter and a pea gravel patio can cost noticeably more than a crushed stone one of the same size.

Can you use both?

Yes, and for decorative areas you generally should. The standard build is a compacted crusher run base with a pea gravel surface course on top. You get the stability of angular stone underneath and the comfort of rounded stone where you walk.

Both the gravel patio calculator and the pea gravel calculator size the two layers separately so you can order them as the different materials they are.