#9 Stone: Size, Uses, Weight and How Many Tons

#9 stone is a fine crushed aggregate on the ASTM size chart, running from about the No. 4 sieve down to the No. 16 sieve. In plain terms, the pieces are smaller than pea gravel and coarser than sand: think coarse grit or fine chips rather than the golf-ball rock you see in a French drain. Quarries sell it for concrete mixes, asphalt surface courses, thin fill lifts and as a choke layer over coarser stone. For planning, figure about 1.35 to 1.5 tons per cubic yard. This guide covers the size, how #9 compares with #8 and #10, where it works, how deep to use it and how to figure the tons.

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What the “#9” in #9 stone means

The number comes from ASTM D448 (AASHTO M 43 is the matching highway table), the same size chart that names #4, #57 and #8. Each size number is a gradation: a permitted share of stone passing a series of screens, not a single particle diameter. Size No. 9 has a nominal range of No. 4 (about 3/16 inch) down to No. 16 (about 1/16 inch). Nearly everything passes a 3/8-inch screen, most of it passes No. 4, and only a small share gets through No. 16.

Screen opening	Share passing, by weight (size No. 9)
3/8 inch	100%
No. 4 (about 3/16 in)	85 to 100%
No. 8	10 to 40%
No. 16	0 to 10%
No. 50	0 to 5%

Those middle rows are why #9 feels like fine chips instead of open drain rock: most of the pile is smaller than a pea, and very little dust is left. Ask the yard for its gradation sheet if a plan or permit calls out ASTM size No. 9 by name.

A naming trap shows up at many yards. Some regions sell a product they call “#9 limestone,” “9 chip” or “#9 gravel” that runs closer to 1/4 to 3/8 inch and behaves more like a fine #8 stone. That trade name is not always the ASTM No. 9 band. If your job needs the fine ASTM grade, say “ASTM D448 size No. 9” and confirm the sieve range before the truck loads.

#9 stone vs #8, #10 and pea gravel

As the size numbers climb, the rock gets smaller. Two-digit blends such as #57 and #67 cover a wider band.

Size	Nominal range	Common jobs
#57	1 in down to about 3/16 in	Drainage, concrete, driveway topping
#67	3/4 in down to about 3/16 in	Concrete, smaller pipe bedding
#8	3/8 in to No. 8 sieve	Pavers bedding, exposed aggregate, permeable surfaces
#9	No. 4 to No. 16	Fine concrete aggregate, thin fill, choke and surface mixes
#10 / screenings	No. 4 down to dust	Leveling course, compactable fines
Pea gravel	Often about 1/8 to 3/8 in, rounded	Paths, play areas, decorative beds

#8 is the neighbor people compare most often. #8 still has visible marble-to-pea pieces and larger open voids. ASTM #9 is a step finer, so it packs into smaller gaps and is more often mixed into concrete or asphalt than dumped as a thick drain layer. #10 (screenings) goes all the way to dust and packs into a dense, almost soil-like layer. Pea gravel is usually rounded river or washed stone in a similar size band; it rolls more and does not lock like angular crushed #9.

Where #9 stone works well

Concrete and mortar mixes. Size No. 9 sits in the fine-aggregate range used in some concrete and masonry mixes when the engineer’s mix design calls for it. The yard may bag it as manufactured sand or fine crushed stone rather than labeling the pile “#9.”
Asphalt surface and chip courses. Fine crushed stone in this band shows up in surface mixes and as cover aggregate on some chip-seal and slurry jobs. The exact grade is set by the mix or the road agency, not by the nickname on the pile.
Choke stone over an open-graded base. A thin lift of fine chips worked into the top of coarser rock (for example #57) helps lock the surface without sealing it the way dense screenings can. See choke stone over an open-graded base.
Thin leveling and fill lifts. Where you need a shallow, clean fill that still drains better than soil, fine crushed stone fills ruts and low spots before a finer topping goes on.
Walkways and patio bedding under the right system. Some paver and slab details allow a fine crushed stone bedding layer. Follow the manufacturer’s size chart; many call for #8 or a washed bedding sand rather than raw #9.

Where #9 stone falls short

Do not treat ASTM #9 as French-drain rock. The pieces are too small and nest too tightly to move water the way #57 or 3/4 inch clean stone does. As a driveway top course by itself it can feel dusty when dry and sticky when wet, and it lacks the larger stone that carries tire loads. For a packed driveway surface, a dense-graded product such as crusher run, ABC or a local road base usually works better. Under pavers, use the bedding size the paver maker specifies rather than assuming any fine chip will do.

How much #9 stone weighs

Fine crushed stone in this size range usually weighs about 1.35 to 1.5 tons per loose cubic yard, roughly 2,700 to 3,000 pounds. A planning figure of 1.4 tons per yard is reasonable for most limestone and granite piles. Dense trap rock runs a little heavier; wet stone off a washed pile weighs more until it drains. Use the quarry’s listed weight when it gives one. Our chart of crushed stone weight per yard covers other products.

Because the grading is finer than open drain rock, you may see a bit more settlement when you compact it. Plan on about 10 percent extra for uneven subgrade, compaction and spillage on thin lifts; add more if the stone is going into a mix where the batch plant meters by weight anyway.

How deep to lay it

Choke layer over coarse stone: often about 1/2 to 1 inch worked into the top, not a thick separate course.
Leveling fill before a base or slab: usually 1 to 2 inches after compaction, unless the plans say otherwise.
Pavers or slab bedding: whatever depth the system chart lists, commonly around 1 inch of the specified bedding material.
Concrete or asphalt mix: the plant meters the aggregate by weight into the mix; you are not placing a free depth in the field.

These are starting points. If an engineer, the paver manufacturer or your permit sets a section, follow that.

How many tons of #9 stone you need

For a placed layer, measure the area in square feet and the depth in inches:

Cubic yards = area (sq ft) × depth (in) ÷ 324
Tons ≈ cubic yards × 1.4, or area × depth × 0.0043
Area one ton covers ≈ 230 ÷ depth (in), in square feet

Then add about 10 percent.

Depth	Approx. area one ton covers	Tons per 100 sq ft
1 inch	about 230 sq ft	about 0.4
2 inches	about 115 sq ft	about 0.9
3 inches	about 77 sq ft	about 1.3

Example: a 1-inch choke over a 12 by 40 foot stone pad. 12 × 40 = 480 square feet. 480 × 1 ÷ 324 = about 1.5 cubic yards. 1.5 × 1.4 = about 2.1 tons. With 10 percent extra, order about 2.5 tons. Our guide to tons of gravel in a dump truck shows how that fits on a small dump or pickup loads.

Example: leveling a 10 by 20 foot patio pad 2 inches deep. 200 × 2 ÷ 324 = about 1.2 cubic yards, or about 1.7 tons. Order about 2 tons.

Placing #9 stone

Confirm the product against the sieve range you need. Do not rely on the nickname alone.
Shape and compact the layer below so the fine stone does not disappear into soft spots.
Spread thin lifts. Fine stone is easy to over-apply; a thick dump of #9 can seal a drain layer you meant to keep open.
For a choke layer, broom or blade the chips into the voids of the coarser stone, then compact lightly so the pieces seat without crushing into dust.
Keep soil and clay out of the pile. Contaminated fines turn a clean #9 into mud after the first rain.

Buying tips

Ask for ASTM D448 size No. 9 and the gradation sheet. If the yard only sells a coarser “9 chip,” decide whether that product still fits the job.
Compare crushed vs rounded. Angular crushed faces lock better in a choke or fill. Rounded fine gravel drains and looks neat but shifts more underfoot.
Check moisture. Washed fine stone can leave the yard wet and weigh heavy on the ticket; dry stockpile stone is easier to spread thin.
Mind delivery minimums. A thin choke layer may be fewer tons than a truck wants to haul, so combine the order with other stone or plan for a small-load fee.

Questions people ask

What size is #9 stone?

ASTM size No. 9 runs from about the No. 4 sieve down to the No. 16 sieve. Nearly all of it passes a 3/8-inch screen, and only a small share is as fine as dust. Some yards sell a coarser product they also call #9, so confirm the sieve range.

What is the difference between #9 and #8 stone?

#8 is larger, from about 3/8 inch down to the No. 8 sieve, with more visible pea-to-marble pieces. ASTM #9 is finer chips used more often in mixes, thin fills and choke layers. #8 has bigger voids; #9 nests tighter.

Is #9 stone the same as stone dust?

No. Stone dust and ASTM #10 screenings run from about No. 4 all the way to powder and pack into a dense layer. #9 stops around the No. 16 sieve and stays more like fine chips than flour.

How much does a yard of #9 stone weigh?

Usually about 1.35 to 1.5 tons per cubic yard, roughly 2,700 to 3,000 pounds. Use 1.4 tons as a planning figure, or the quarry's listed weight when it gives one.

Can you use #9 stone for a driveway?

Not as the main load-bearing or drainage layer. It can work as a thin choke or leveling lift over coarser stone. For a packed surface, use crusher run, ABC or another dense-graded base instead.

Is #9 stone good for a French drain?

No. The pieces are too small and pack too tightly to move water the way #57 or other clean open-graded stone does. Keep #9 for mixes, choke and thin fill.

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