How much gravel do I need?
Cubic yards of gravel = square feet × depth in inches ÷ 324; tons = cubic yards × 1.35–1.55.
- Volume: length × width in feet × depth in inches ÷ 324 = cubic yards. A 20 × 10 ft area at 3 inches is 200 × 3 ÷ 324 = 1.85 cubic yards.
- Weight: multiply by the weight of a cubic yard. The US Army's earthmoving tables give loose gravel as 2,700–3,000 lb per cubic yard dry and 2,800–3,100 lb wet,[1] which is 1.35–1.55 US tons. A New Mexico state conversion table uses a single figure of 1.42 tons per cubic yard for ¼–2 inch gravel.[2]
- Result: 1.85 yd³ × 1.35–1.55 = about 2.5–2.9 tons.
A rule of thumb from UC Master Gardeners says one ton of gravel covers 80–120 sq ft at 2 inches deep.[3] The density math agrees: a ton is about 0.64–0.74 cubic yards, which covers 104–120 sq ft at 2 inches.
Gravel calculator by square feet: common areas
A 10 × 20 ft area 3 inches deep takes about 2.5–2.9 US tons of gravel; the table covers other sizes and depths.
| Area (ft) | 2 in | 3 in | 4 in | 6 in |
|---|---|---|---|---|
| 10 × 10 | 0.8–1 | 1.2–1.4 | 1.7–1.9 | 2.5–2.9 |
| 10 × 20 | 1.7–1.9 | 2.5–2.9 | 3.3–3.8 | 5–5.7 |
| 12 × 24 | 2.4–2.8 | 3.6–4.1 | 4.8–5.5 | 7.2–8.3 |
| 20 × 20 | 3.3–3.8 | 5–5.7 | 6.7–7.7 | 10–11.5 |
| 12 × 50 | 5–5.7 | 7.5–8.6 | 10–11.5 | 15–17.2 |
| 20 × 40 | 6.7–7.7 | 10–11.5 | 13.3–15.3 | 20–23 |
How deep should gravel be?
Two inches is the practical minimum for a garden path, 4 inches suppresses weeds, and paver bases need at least 4 inches compacted.
| Use | Depth | Source |
|---|---|---|
| Garden path | 2 in is a practical minimum; 4 in if stepping stones or pavers are set in it | [3] |
| Rock or gravel mulch | 2–3 in | [5] |
| Gravel mulch to improve infiltration | 3 in | [4] |
| Gravel mulch to suppress weeds | 4 in, stones no larger than about ½ in | [4] |
| Decomposed granite ground cover | 1–2 in | [6] |
| Compacted base under patio pavers | at least 4 in (100 mm) | [7] |
| Compacted base under driveway pavers | at least 6 in (150 mm) | [7] |
| Gravel access road for vehicles (NRCS Ohio, 2010) | at least 8 in compacted, plus any wearing layer | [9] |
| Public gravel roads (NYS LTAP) | not less than 12 in | [10] |
Driveways are a different job, built in compacted layers; see the driveway gravel calculator. Every inch of depth takes about 3.1 cubic yards, or 4.2–4.8 US tons, of gravel per 1,000 sq ft.
Gravel sizes and what the numbers mean
US aggregate sizes follow the AASHTO numbering from 1 (largest) to 10 (screenings). Two-digit sizes are blends: #57 combines #5 and #7.[11]
| Size | Roughly |
|---|---|
| #1 | 4 in to ¾ in |
| #3 | 2½ in to ½ in |
| #57 | about 1 in down to 3/16 in (No. 4 sieve) |
| #8 | about 3/8 in down to the No. 8 sieve |
| #10 | screenings, under 3/8 in |
Size ranges are from Penn State's Aggregate 101 guide.[11] No. 8 stone is also the bedding layer for permeable pavers.[8] Bagged all-purpose gravel can be much finer: one manufacturer's product has a top size of about 3/8 in (9.5 mm).[12]
Crushed gravel or rounded gravel?
Rounded, river-run gravel such as pea gravel never packs down completely, while angular material such as decomposed granite packs into a nearly solid surface.[3] Pick crushed, angular stone where you want a firm surface, and rounded stone where you want it loose and free-draining. For #57 stone and crusher run, the stone calculator explains the grades.
Compaction
Order about 17% more gravel than the finished volume of any layer you will compact.
Ordering for a compacted layerLoose sand or gravel shrinks to about 0.86 of its volume when compacted, so each compacted cubic yard needs about 1.17 loose cubic yards.[1] Add that as compaction in the paver base calculator rather than as general extra.
Bagged gravel
Bagged decorative stone is commonly 0.5 cu ft per bag,[13] so a cubic yard is 54 bags. Pick the bag size in the calculator to see the count. For larger decorative stone, use the river rock calculator; for metric orders in tonnes, the gravel calculator in tonnes.
Bags or bulk gravel?
A cubic yard of gravel equals 54 bags of 0.5 cu ft, so even a small path adds up to dozens of bags.
| Area | 2 in | 3 in | 4 in |
|---|---|---|---|
| 50 sq ft | 0.31 yd³ (17 bags) | 0.46 yd³ (25 bags) | 0.62 yd³ (34 bags) |
| 100 sq ft | 0.62 yd³ (34 bags) | 0.93 yd³ (50 bags) | 1.23 yd³ (67 bags) |
| 200 sq ft | 1.23 yd³ (67 bags) | 1.85 yd³ (100 bags) | 2.47 yd³ (134 bags) |
| 400 sq ft | 2.47 yd³ (134 bags) | 3.7 yd³ (200 bags) | 4.94 yd³ (267 bags) |
Compare the bag count with a bulk quote by the yard or ton; the gravel calculator in tons converts the same areas to weight.
Common gravel calculator mistakes
The costliest mistake is ordering the finished volume for a layer that will be compacted: loose gravel shrinks to about 0.86 of its volume, so order about 17% more.[1]
- Using rounded stone for a firm surface. River-run gravel such as pea gravel never packs down completely; angular gravel packs nearly solid.[3]
- Laying a path too thin. Two inches is the practical minimum for a garden path.[3]
- Using large stone to stop weeds. Gravel mulch needs about 4 inches of stones no larger than about half an inch.[4]
- Ignoring weight per yard. Loose gravel weighs 2,700–3,100 lb per cubic yard, so a "ton" is only about 0.65–0.74 yards.[1]
- Comparing tons with tonnes. A tonne is about 10% heavier than a US ton.[14]
How much does a yard of gravel cost?
A yard of gravel costs your supplier's price per cubic yard; if they price by the ton, a loose yard is about 1.35–1.55 US tons, so multiply the ton price by that.[1] Prices vary by region, stone and delivery distance, so this site does not publish them. Enter your quotes in the price fields above to see the bulk, by-weight and bagged totals for your own area, plus any delivery charge.
| Material | US tons per cubic yard | Price per yard = price per ton × |
|---|---|---|
| Gravel / crushed stone | 1.35–1.55 | 1.35–1.55 |
| Paver base / road base | 1.25–1.62 | 1.25–1.62 |
The base range combines a state conversion table (1.25 tons per yard) with Penn State's ordering figure for road aggregate (about 1.62).[2][15]
Frequently asked questions
How much does a yard of gravel weigh?
Loose gravel weighs 2,700–3,000 lb per cubic yard dry and 2,800–3,100 lb wet, or about 1.35–1.55 US tons.[1]
How many tons of gravel do I need for a 20 × 20 area?
At 4 inches: 400 × 4 ÷ 324 = 4.94 cubic yards, which is about 6.7–7.7 tons.
How many square feet does a ton of gravel cover?
About 80–120 sq ft at 2 inches deep, roughly half that at 4 inches.[3]
How many bags of gravel make a yard?
54 bags of 0.5 cu ft.
How do I convert tons of gravel to cubic yards?
Divide the tons by 1.35–1.55. The tons to cubic yards converter does it for any material.
Sources
- FM 5-434 Earthmoving Operations, Tables 1-1 and 1-2 (material weights, swell and conversion factors)
- Conversion Factors for Construction Materials and Common Minerals (from BLM Handbook H-3890-1)
- Gravel Pathways in the Garden
- Mulching (CMG GardenNotes #245)
- Water-Wise Landscaping: Mulch
- Ground Covers for Arizona Landscapes (AZ1110)
- Construction of Interlocking Concrete Pavements (PAV-TEC-002-22)
- Glossary of Terms for Segmental Concrete Pavement (PAV-TEC-001-23)
- Conservation Practice Standard 560: Access Road (Ohio, archived)
- How thick should the gravel be on a reconstructed road?
- Aggregate 101 (DSA Handbook Appendix F)
- QUIKRETE Sand & Gravel Products data sheet
- Hardscapes product line
- NIST Handbook 44, Appendix C: General Tables of Units of Measurement
- Driving Surface Aggregate (DSA) Handbook