How Many Bags of Cold Patch Do I Need? (With a Simple Formula)

For a typical 50-pound bag of cold patch, here's the shortcut: multiply the length by the width in feet, multiply by the depth in inches, and divide by 6. Round up and add one bag for compaction and overfill. A 2-foot by 3-foot hole that's 2 inches deep works out to 2 bags, so buy 3.

That shortcut is based on a common yield of about half a cubic foot per 50-pound bag once it's compacted, which works out to roughly 6 sq ft when laid an inch thick. Products vary, and some brands yield noticeably less per bag, so check the yield printed on your bag and adjust. Below is the math, a few worked examples, and tips so you don't end up making a second trip to the store.

Cold patch asphalt repair → Cold patch not hardening →

Where the "Divide by 6" Rule Comes From

One well-known brand's data sheet lists its 50-pound bag as yielding about 0.5 cubic feet compacted, or about 6 square feet at a 1-inch depth. Several other brands land in a similar range.

So:

• Hole volume (cubic feet) = L × W × D ÷ 12, with L and W measured in feet and D in inches
• Bags = hole volume ÷ 0.5

Dividing by 12 and then by 0.5 is the same as dividing by 6. That's the whole trick.

Bags = L (ft) × W (ft) × D (in) ÷ 6

If your bag lists a different yield, swap in its number. For a product that yields 0.4 cubic feet per bag, the formula becomes L × W × D ÷ 4.8.

Quick Reference Table

Assumes about 0.5 cubic feet of compacted patch per 50-pound bag. Round up, then add a bag.

Repair size	1 inch deep	2 inches deep	3 inches deep
1 ft × 1 ft	0.2 bag	0.3 bag	0.5 bag
2 ft × 2 ft	0.7 bag	1.3 bags	2 bags
2 ft × 3 ft	1 bag	2 bags	3 bags
3 ft × 3 ft	1.5 bags	3 bags	4.5 bags
4 ft × 4 ft	2.7 bags	5.3 bags	8 bags

Worked Examples

Example 1: A rectangular hole

A hole measures 30 inches by 18 inches and averages 2 inches deep.

• Convert to feet: 2.5 ft × 1.5 ft
• 2.5 × 1.5 × 2 = 7.5
• 7.5 ÷ 6 = 1.25 bags
• Buy 2, plus 1 spare = 3 bags

Example 2: A round pothole

Measure across the widest part. Say it's 20 inches across (about 1.67 ft) and 3 inches deep.

• Area of a circle ≈ 0.785 × diameter × diameter
• 0.785 × 1.67 × 1.67 ≈ 2.2 sq ft
• 2.2 × 3 = 6.6
• 6.6 ÷ 6 = 1.1 bags
• Buy 2 to 3 bags

Example 3: A long, narrow strip

A settled strip along the edge of a driveway is 10 feet long, 8 inches wide (0.67 ft), and 1.5 inches deep.

• 10 × 0.67 × 1.5 = 10
• 10 ÷ 6 = 1.7 bags
• Buy 3 bags

Why You Should Always Buy Extra

Three reasons people come up short:

1. Holes are deeper than they look. Once you clean out the loose junk, a 2-inch hole often turns into 3.
2. Compaction. Loose patch shrinks when you tamp it. You need to mound it a bit above the surface before compacting.
3. Irregular shapes. Potholes rarely have neat sides. Measure the widest points.

Unopened bags usually keep well if stored dry and out of the sun, so an extra bag isn't wasted. It's there for the next pothole.

Deep Holes: Use Gravel First

Cold patch is meant to be placed in fairly thin layers. If a hole is more than about 3 to 4 inches deep, fill the bottom with crushed stone, the angular kind that locks together, and tamp it hard. Then put the cold patch on top.

This saves money, since stone costs far less than bagged patch, and it gives a firmer repair. For example, a 2 × 2 foot hole that's 6 inches deep would take about 4 bags of patch alone. Fill the bottom 3 or 4 inches with tamped stone and you might need only 2 bags.

How to Measure Accurately

• Clean first. Remove loose asphalt, dirt, water, and debris, then measure.
• Square it up. For best results, cut the edges of the hole square with a chisel or saw. This also makes measuring easier.
• Take depth in a few places and average them.
• Write it down in inches, then convert length and width to feet by dividing by 12.

Installing for the Best Result

• Place patch in lifts of about 1 to 2 inches and compact each one before adding the next. Check your bag's instructions, since some products specify thinner lifts.
• Use a hand tamper, a plate compactor, or drive a car tire slowly over it with plywood on top.
• Finish slightly above the surrounding pavement. It settles a bit under traffic.
• Dust the top with sand if it stays sticky.

Bottom Line: How Many Bags of Cold Patch You Need

Measure the cleaned hole, multiply length by width in feet and by depth in inches, and divide by 6. Round up and grab one extra bag. For deep holes, put tamped stone in the bottom first. With that simple math you'll buy the right amount the first time.