Gravel comparisons: which to choose
The stone-vs-stone decisions people actually get stuck on — #57 vs #67, CA6 vs CA7, pea gravel vs river rock — side by side, with a plain verdict for each. When you've picked one, the calculator gives you the quantity.
Pea gravel vs. river rock
| Pea gravel | River rock | |
|---|---|---|
| Size | 3/8" rounded | 1"–3" rounded |
| Shape | Smooth, small | Smooth, larger |
| Compacts? | No — rolls | No — stays loose |
| Drainage | Good | Good |
| Weight | ~2,450 lb/yd³ | ~2,550 lb/yd³ |
| Best for | Paths, play areas, dog runs | Decorative beds, dry creeks, splash zones |
Both are rounded and decorative, and neither belongs on a driveway. Pick pea gravel where people walk — it's smaller and comfortable underfoot. Pick river rock where you want the look — larger stones read as a feature, not a surface. Size either with the pea gravel or river rock calculator.
Crushed stone vs. pea gravel
| Crushed stone | Pea gravel | |
|---|---|---|
| Shape | Angular, sharp faces | Rounded, smooth |
| Compacts? | Yes — interlocks | No — shifts |
| Under traffic | Stable | Migrates, ruts |
| Drainage | Good (clean grades) | Good |
| Best for | Driveways, bases, drainage | Paths, decorative beds |
Angular crushed stone interlocks and compacts, so it holds under vehicles and makes a base. Rounded pea gravel rolls, so it's for decoration and foot traffic, not structure. Full breakdown in the gravel vs. crushed stone guide.
#57 vs. #67 stone
| #57 stone | #67 stone | |
|---|---|---|
| Nominal size | ~3/4" (up to ~1") | ~3/4" (up to ~3/4") |
| Top size | Slightly larger | Slightly smaller/tighter |
| Fines | None (clean) | None (clean) |
| Most used for | Driveways, French drains, drainage | Concrete aggregate, tighter surfaces |
| Availability | Most-stocked grade | Common at concrete plants |
Nearly interchangeable — both are clean ~3/4-inch stone. Use #57 for driveways and French drains (it's the grade every yard stocks), and #67 when a spec calls for it or you're mixing concrete. If a yard has one and not the other, either works for drainage.
#57 vs. #4 stone
| #57 stone | #4 stone | |
|---|---|---|
| Size | ~3/4" | 1.5"–2.5" |
| Walkable? | Yes | No — rolls an ankle |
| Role | Top course, drainage | Deep base, heavy drainage, erosion |
| Weight | ~2,750 lb/yd³ | ~2,650 lb/yd³ |
| Best for | Driveway surface, paver base, French drains | Sub-base under #57, culvert beds |
#4 is much larger — a deep drainage or sub-base layer, not a surface. #57 is the walkable, driveable top course. On a soft or heavy-traffic driveway you often use both: a #4 sub-base under a #57 top. Size either on the crushed stone calculator.
CA6 vs. CA7
| CA6 | CA7 | |
|---|---|---|
| Type | Dense-grade base (with fines) | Clean 3/4" stone (no fines) |
| Compacts? | Yes — packs hard | No — stays open |
| Drainage | Slower (fines fill voids) | Free-draining |
| Closest grade | ≈ 21AA / Class 5 / ABC | ≈ #67 / clean 3/4" |
| Best for | Driveway & paver bases, shed pads | Behind retaining walls, around drain pipe |
CA6 has fines, so it compacts to a hard base — the right material under a paver patio or driveway. CA7 is a clean, open stone for drainage where you want water to move, not a compacted base.
CA6 vs. #57 (base vs. top course)
| CA6 (base) | #57 (top / drainage) | |
|---|---|---|
| Fines | Yes — compacts | None — clean |
| Job | Load-bearing base | Finished surface or drainage |
| Compaction | Packs to near-concrete | Locks loosely, drains |
| Use together? | Yes — CA6 base under #57 top | Yes — the standard driveway build |
Not either-or — they're two layers. CA6 is the compactable base; #57 is the clean top course or drainage stone. A proper driveway uses 4" of CA6 under 2" of #57.
Crusher run vs. #57
| Crusher run | #57 stone | |
|---|---|---|
| Fines | Yes — compacts hard | None — clean |
| Drainage | Sheds water on top | Drains through |
| Role | Compactable driveway base | Top course, French drains |
| Cost | Usually cheaper | Slightly more |
Crusher run (same idea as ABC/CA6) has fines and compacts, so it's a cheap, solid driveway base. #57 is clean and free-draining — a top course or drain rock, not a compactable base. Many driveways use crusher run below and #57 on top. Size either with the crusher run calculator.
Class 1 vs. Class 5 gravel
| Class 1 (varies) | Class 5 (varies) | |
|---|---|---|
| What it is | A DOT aggregate spec | A DOT dense-grade base spec |
| Numbering | State-specific — not national | State-specific — not national |
| Common use | Coarser fill/base in some states | Compactable driveway/road base (Upper Midwest) |
| National equivalent | Confirm locally | ≈ CA6 / 21AA / crusher run |
Careful here: gravel "classes" are set by each state DOT, not a national scale, so a "Class 1" or "Class 5" in one state isn't the same product in another. In the Upper Midwest, Class 5 is a common dense-grade compactable base (≈ 21AA / CA6). Always confirm the exact class spec with your local supplier.