How this calculator works
Repairs are usually done with 50 lb bags of cold patch, so the tool converts your pothole dimensions into a bag count and keeps you from over-buying at the hardware store. It multiplies the repair area by the depth to get a volume, multiplies by the mix density for a weight, and divides by the bag weight for a bag count — and gives the total tonnage for larger utility cuts and surface repairs.
For a big repair you would order hot mix by the ton rather than bags; the underlying math is the same as the asphalt tonnage calculator. When the whole surface is worn rather than locally damaged, an overlay is usually the better fix — size it with the asphalt resurfacing calculator.
The formula
Weight (lb) = Area (sq ft) × (Depth in ÷ 12) × Density (lb/ft³)
Bags = Weight (lb) ÷ Bag weight (e.g. 50 lb)
Example: a 2 × 2 ft pothole (4 sq ft) at 2 in and 145 lb/ft³ = 4 × (2 ÷ 12) × 145 = 96.7 lb, or about two 50 lb bags. Cold patch is lighter than hot mix, so a bag of cold patch fills a little more volume than the weight suggests.
Worked examples
Example 1 — a 2 ft × 2 ft pothole, 2 inches deep
- Area:
- 2 ft × 2 ft = 4 sq ft
- Depth:
- 2 in
- Mix density:
- 145 lb/ft³ (hot mix)
- Convert depth: 2 in ÷ 12 = 0.167 ft
- Volume: 4 sq ft × 0.167 ft = 0.667 cu ft
- Weight: 0.667 cu ft × 145 lb/ft³ = 96.7 lb
- Convert to bags: 96.7 lb ÷ 50 = 1.9 bags
Buy: 2 bags of 50 lb patch
Round up to whole bags, and add one if you are overfilling generously — leftover cold patch stores in the bag for the next pothole.
Example 2 — a 3 ft × 5 ft utility cut, 3 inches deep
- Area:
- 3 ft × 5 ft = 15 sq ft
- Depth:
- 3 in
- Mix density:
- 145 lb/ft³ (hot mix)
- Convert depth: 3 in ÷ 12 = 0.25 ft
- Volume: 15 sq ft × 0.25 ft = 3.75 cu ft
- Weight: 3.75 cu ft × 145 lb/ft³ = 543.75 lb
- Convert to tons: 543.75 lb ÷ 2,000 = 0.27 tons
Order about: 0.27 US tons of hot mix
Above roughly a quarter-ton, hot mix delivered by the ton is more economical than bagged cold patch.
Reference data
| Repair | Area | Depth | Approx. weight |
|---|---|---|---|
| Small pothole (2 × 2 ft) | 4 sq ft | 2 in | 97 lb (≈ 2 bags) |
| Driveway strip (1 × 20 ft) | 20 sq ft | 2 in | 483 lb |
| Utility cut (3 × 5 ft) | 15 sq ft | 3 in | 544 lb |
| Large surface patch (10 × 10 ft) | 100 sq ft | 2 in | 2,417 lb (≈ 1.2 t) |
| Density (lb/ft³) | Density (kg/m³) | Note |
|---|---|---|
| 142 lb/ft³ | 2,275 kg/m³ | Low end of the in-place range |
| 145 lb/ft³ | 2,323 kg/m³ | OtherCalculators hot-mix default |
| 148 lb/ft³ | 2,371 kg/m³ | Asphalt Institute “Use 148 PCF” |
Key facts
- A 50 lb bag of cold-patch asphalt covers roughly 4–6 square feet at about 1 inch of depth, depending on the product and compaction.
- A 2 × 2 ft pothole 2 inches deep holds about 97 lb of hot mix at 145 lb/ft³ — roughly two 50 lb bags.
- Cold-patch products are lighter and more variable than hot mix, commonly around 130–145 lb/ft³; hot mix compacts to about 145.
- Patch material is placed loose and compacts down, so overfilling a repair by about 1 inch is standard practice.
Who should use this and when
This is the tool for a specific, bounded repair — a homeowner filling a driveway pothole with bagged cold patch, or a maintenance crew scoping a utility cut. Below about a quarter-ton, buy bags; above it, hot mix by the ton is cheaper per pound. Once you know the material, price a professional fix with the asphalt repair cost calculator, and if the damage is spreading across the whole surface compare it against a full driveway replacement.
Tips and common pitfalls
- Square-cut the hole first. Clean vertical edges down to a solid base give the new mix a shoulder to bind to; patching over crumbling edges fails fast.
- Overfill and compact. Loose patch settles, so mound it about 1 inch proud and tamp with a hand tamper or a vehicle tire until it is tight and flush.
- Read the coverage on your bag. Cold-patch products vary in density; the bag's stated coverage beats a generic figure for an exact count.
- Clear water and debris. A patch placed over standing water or loose grit will not bond — dry and sweep the hole before you fill it.
Repair FAQs
How many bags of asphalt patch do I need?+
Work out the repair volume — area in square feet × (depth in ÷ 12) — multiply by the mix density to get pounds, then divide by the bag weight. A 50 lb bag covers roughly 4–6 square feet at about 1 inch, so a 2 × 2 ft pothole 2 inches deep takes about two bags.
How much area does a 50 lb bag of asphalt patch cover?+
About 4–6 square feet at roughly 1 inch of depth, depending on the product and how much you compact it. Cold-patch mixes list their own coverage on the bag; check it, because a denser mix covers less area per bag than a lighter one.
What is the difference between hot mix and cold patch density?+
Hot mix compacts to about 145 lb/ft³. Cold-patch products are lighter and more variable — data sheets commonly list roughly 130–145 lb/ft³ — so a bag of cold patch fills slightly more volume than the same weight of hot mix. Use the value on your bag for a precise count.
Should I overfill a pothole?+
Yes. Patch material is placed loose and compacts down, so overfill the hole by about 1 inch, then tamp it until it is tight and flush with the surface. Under-filling leaves a depression that collects water and fails quickly.
How should I prepare a pothole before patching?+
Square off the hole with clean, vertical edges down to a solid base, and remove all loose debris and standing water. Cutting the pothole into a rectangle gives the new mix a firm shoulder to bind against, which is what makes a patch last.
How much does it cost to patch a pothole?+
DIY cold-patch bags are inexpensive, but a professional repair is priced by the area and usually runs more per square foot than full paving because of the hand work involved. Estimate a professional job with the asphalt repair cost calculator.
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Estimates & assumptions
- Material weight is computed as area × (depth ÷ 12) × density; bag counts divide that weight by a 50 lb bag and exclude a compaction allowance.
- Hot mix is taken at 145 lb/ft³, inside the Asphalt Institute's 142–148 lb/ft³ in-place range. Cold-patch products are lighter and variable — use the density printed on the bag.
- Coverage-per-bag figures are approximate and depend on the specific product and how firmly it is compacted.
- This tool estimates patch material only; it does not assess whether a repair or a full replacement is the right fix.
Estimates are for planning only. Confirm the product's density and coverage on its packaging before buying material.