Crushed Stone Grades Explained: Sizes and Uses (#57, #411, Rip-Rap)
A plain guide to crushed stone grades by size and job: #57, #67, #8, crusher run / #411, dense-grade vs. clean, and rip-rap, and what each is used for.
Crushed Stone Grades, Explained by Size and Job
Crushed stone is sorted by a numbered grade that tells you the particle size and the fines content. Get the grade right and the base compacts, the drain flows, and the concrete pours clean. Get it wrong and you are hauling material back off the site. Here is what the common numbers actually mean and where each one belongs.
The grade number is set by the screen the crusher runs behind, not by the rock type. The same granite or trap rock can leave the plant as a dozen different products depending on the deck it passed over. That is worth remembering when you are speccing a machine to make a spread — the screen decides the salable size, and we will come back to that.
The grades operators ask for most
- #1 stone (2 to 4 inch): Large, angular, mostly clean. Backfill for big voids, heavy sub-base under access roads, and erosion control on slopes. Too coarse to walk on or compact tight.
- #3 stone (1/2 to 2 inch): Classic railroad ballast size. Also a base over soft subgrade where you need drainage and load spread before finer layers go down.
- #5 stone (1 to 1-1/2 inch): A base course for driveways and light pads, and a transition layer between big rock below and finer stone above.
- #57 stone (about 3/4 inch, clean): The workhorse. Almost no fines, so it drains hard. Driveways, slab and road base, French drains, pipe bedding, and retaining-wall backfill. When someone says "gravel" without thinking, they usually mean #57.
- #67 stone (3/4 inch and down): A hair smaller than #57 with a touch more range. Slab base, shoulders, and a common aggregate in ready-mix concrete.
- #8 stone (3/8 inch): Pea-size, clean. Concrete mixes, decorative top layers, and finish stone where you want a smaller look.
- #10 screenings / stone dust (fines): Whatever passes the smallest deck. Paver setting bed, joint fill, and the binder that lets a base lock up.
Dense-grade vs. clean, and where each wins
The single most useful distinction on a jobsite is clean vs. dense-grade.
Clean stone (#57, #67, #8) has the fines screened out. Water runs straight through it, so it is what you want for drainage, bedding, and anywhere frost heave or standing water is the enemy. The tradeoff: clean stone does not compact into a hard, locked surface — it stays loose and shifts underfoot.
Dense-grade — most people know it as crusher run or #411 — is #57-size stone blended back with #10 stone dust. The fines fill the gaps between the larger pieces, so it compacts to a tight, load-bearing surface that sheds water off the top instead of through it. That makes crusher run the default for driveway and road base, parking pads, and any subgrade you need to drive on. It is not a drainage product.
- Need it to drain? Go clean: #57, #67, bedding stone.
- Need it to hold weight and stay put? Go dense-grade: crusher run / #411.
- Rip-rap is its own category — fist-size to boulder-size armor stone for channel banks, culvert outlets, and shoreline protection. It is graded by weight and diameter rather than a screen number, and it is meant to break the energy of moving water, not to compact.
Why the grade is really a screening question
Every one of these products comes off the same crushing circuit — the numbers just reflect where the material landed on the screen deck. An operator who wants to sell #57, crusher run, and a decorative 3/8-inch spread out of one pit is really speccing screen media and deck configuration, not three different crushers. If you are building or expanding a spread and trying to figure out which crusher and screen combination will hit the grades your market buys, that is exactly the kind of sourcing question RPG Equipment works through every week. It is worth browsing current crusher and screen listings with your target products in mind before you commit to a machine.
The short version: match the grade to the job — clean to drain, dense-grade to hold, rip-rap to armor — and remember the screen behind the crusher is what turns rock into a product someone will pay for.
Have questions about crushed stone grades or the crushing and screening equipment behind them? Contact RPG Equipment — we work with buyers and sellers across the US and Canada.
RPG Equipment is a heavy equipment brokerage based in Worcester, MA specializing in grinders, crushers, screeners, and material processing equipment. Contact us to buy or sell equipment, or browse more articles.