Gravel is sorted by size (a numbered grade from #1 down to fine #10 screenings) and by type (pea gravel, crushed stone, crusher run, river rock and more). A higher grade number means a smaller stone. Match angular, compactable stone to structural jobs and rounded stone to decorative ones.
How is gravel sized?
Gravel is graded by the size of screen the crushed stone passes through, under the ASTM D448 and AASHTO standards used across the US. The result is a numbered grade — and the counter-intuitive part is that a bigger number means a smaller stone. #1 is a chunky 2–4 inch rock, #57 is a familiar ¾-inch driveway stone, and #10 is a fine dust. Once you know the grade, you know roughly how the stone behaves: large grades bridge and drain, mid grades balance drainage and stability, and fine grades bind and level.
The common gravel sizes chart
You will meet a handful of grades again and again at the yard. This table covers the ones that matter for driveways, drainage and landscaping.
| Grade | Stone size | Best for |
|---|---|---|
| #1 | 2–4 in | Heavy fill, erosion control, culverts |
| #3 | 1–2 in | Driveway & road base layer |
| #57 | ¾–1 in | Driveways, drainage, concrete mix |
| #67 | ¾ in and down | Base, backfill, concrete |
| #8 | ⅜ in | Paths, top dressing, paver joints |
| #10 (screenings) | Dust–fines | Paver base, binding, leveling |
Gravel types by material and shape
Beyond size, gravel is described by what it is and how it is shaped — and shape decides whether it locks together or stays loose. These are the types you will choose between:
- Pea gravel — small, rounded, smooth stones in natural colors. Comfortable and decorative; great for paths and patios, poor for driveways. Size it with the pea gravel calculator.
- Crushed stone — machine-crushed rock with sharp, angular faces that compact into a firm surface. The structural workhorse for bases and driveways.
- Crusher run — crushed stone blended with stone dust; the fines bind when compacted, making it the top choice for a compactable base.
- River rock — larger, water-smoothed stones (1 inch and up), used decoratively and in dry creek beds and drainage.
- Crushed limestone — a lighter, pale angular stone popular for bases and rural paths; compacts well and is often inexpensive.
- Decorative gravel — marble chips, lava rock and colored aggregates chosen for looks in feature beds and borders.
What is #57 gravel and crusher run?
These two come up more than any others, so they are worth knowing well. #57 gravel is a clean, ¾-to-1-inch crushed stone with no fines — the gaps between stones let water drain straight through, which is why it is used for French drains, driveway top layers and as concrete aggregate. Because it has no dust, it does not compact into a hard crust; it stays loose but stable. Crusher run is the opposite by design: crushed stone with its dust left in, so when you compact it the fines lock the whole layer together into a near-solid base. Use crusher run where you want firmness (a base), and #57 where you want drainage (a top layer or trench).
Gravel, crushed stone and stone dust — the terms explained
Yards and catalogs use these words loosely, which trips people up. Here is the plain distinction. Gravel is the umbrella term for small loose stone, whether it was crushed at a quarry or worn round in a river. Crushed stone specifically means rock mechanically broken into angular pieces, so it always has sharp faces — that is what makes it compactable. Stone dust (also screenings, or #10) is the powdery fine material left after crushing; on its own it packs into a smooth setting bed for pavers. When a supplier says “gravel” they usually mean a crushed product like #57, and when they say “round” or “river” they mean the smooth, decorative kind. If a listing does not state a grade number, ask — the number is the difference between a stone that drains and one that binds.
Does gravel size change how much you need?
Size does not change the volume you calculate, but it changes how that volume settles. Large, angular grades like #3 leave big voids and bridge across gaps, so a base layer of them compacts down noticeably as the stones lock together — order for the loose depth, not the finished one. Fine grades and crusher run, with their dust filling every gap, compact far less and cover more predictably. Rounded pea gravel barely compacts at all but migrates underfoot, so paths need edging to hold the depth. Whatever the grade, the gravel calculator works in volume and already adds a 10% waste allowance, which absorbs most of the settling difference between sizes — bump it toward 15% for a deep base of large angular stone.
What about #411, #21A and other blends?
Alongside the clean single-size grades, yards sell dense-graded blends aimed at bases. #411 is #57 stone mixed with stone dust — essentially a finer crusher run that compacts hard yet still drains, popular for driveways and paver bases. #21A and #21B (called “crush and run” in some regions) are similar dense-grade aggregates of crushed stone and fines. The naming varies by state and quarry, so if a blend is not on the standard chart, ask what size stone and how much dust it contains — that tells you whether it will compact firm (more fines) or drain freely (fewer fines).
Which gravel size should you use?
Match the stone to the job and the finished surface takes care of itself:
| Project | Recommended |
|---|---|
| Driveway base | #3 or crusher run |
| Driveway surface | #57 crushed stone |
| Walking path / patio | Pea gravel or #8 |
| French drain / drainage | #57 clean stone |
| Paver base | Crusher run + #10 screenings |
| Decorative bed | Pea gravel, river rock, decorative |
Once you have picked a size and type, head to the gravel calculator to turn your area and depth into the exact cubic yards and tons to order, or read how much gravel do I need for the full method.