How Much Ice Melt Do I Need? Pounds per Storm by Driveway Size and Temperature

A two-car driveway (20 × 24 ft) plus a 4 × 40 ft front walk is 640 sq ft. At 23 to 28°F, a Dane County, Wis., rate chart puts that at 1.5 to 2.9 lb of rock salt per storm, so one 50 lb bag covers at least 17 storms if you shovel first.

Quick pick: shovel, then spread rock salt at 2.3 lb per 1,000 sq ft and go up only as it gets colder. Below 15°F, use calcium chloride or sand.

Rule of thumb: a 12-ounce coffee cup of salt covers 10 sidewalk squares or a 20 ft driveway (Rice Creek Watershed District).

How much ice melt per storm

Pounds of rock salt per storm at 28-32°F / 23-28°F / 15-23°F pavement, using the top of each Dane County range (2.3 / 4.5 / 6.8 lb per 1,000 sq ft).

4 × 40 ft walk (160 sq ft): 0.37 / 0.72 / 1.09 lb

10 sidewalk squares (250 sq ft): 0.57 / 1.12 / 1.70 lb

20 × 24 ft driveway (480 sq ft): 1.10 / 2.16 / 3.26 lb

Driveway + walk (640 sq ft): 1.47 / 2.88 / 4.35 lb

24 × 40 ft driveway (960 sq ft): 2.21 / 4.32 / 6.53 lb

The low end of every range is 2.3 lb, so start there.

The math, step by step

☐ Area: length × width for each surface, then add. 20 × 24 = 480; 4 × 40 = 160; total 640 sq ft.

☐ Rate: pick it from pavement temperature. At 25°F, rock salt is 2.3 to 4.5 lb per 1,000 sq ft.

☐ Pounds per storm = area ÷ 1,000 × rate. 640 ÷ 1,000 × 4.5 = 2.88 lb.

☐ Season = pounds per storm × storms. 2.88 × 10 = 28.8 lb, about one 50 lb bag with some left over.

☐ Second pass: the chart says ½ to the full first rate, not double.

Dane County's chart counts 40 five-by-five sidewalk squares as 1,000 sq ft, which is why 10 squares is 250.

Below 15°F: switch products

Rock salt and salt blends are grayed out on the Dane County chart below 15°F, and the Rice Creek card says salt doesn't melt ice when pavement is below 15 degrees.

0 to 15°F: bagged calcium or magnesium chloride, 2.3 to 6.8 lb per 1,000 sq ft.

-5 to 0°F: the same products, 6.8 lb per 1,000 sq ft.

Below -5°F: plow only; sand for grip. Sand doesn't melt anything; it adds traction.

Dogs and ice melt

The ASPCA (Jan. 2026) says no rule controls the "pet safe" label, so read the ingredient list.

☐ Calcium, potassium and magnesium chloride can cause bloody vomiting or diarrhea if eaten, plus electrolyte changes.

☐ Pet-friendly melts usually contain urea or magnesium chloride.

☐ Wipe or rinse paws after walks, or try booties.

☐ Keep dogs inside while you spread and don't overdo it.

New concrete and pavers

The Pennsylvania Aggregates and Concrete Association says no deicer on concrete less than one year old. After that, sodium or calcium chloride is generally fine on good, dense concrete. Magnesium chloride, potassium chloride, CMA, urea and nitrogen salts cause much more damage; never use ammonium sulfate or ammonium nitrate.

Note the conflict: the "pet-friendly" ingredients are the harder ones on concrete. For pavers, see our ice melt for concrete and pavers guide.

Spreader and cold-weather melt (#ad)

As an Amazon Associate, Curb Calc earns from qualifying purchases.

CHAPIN 8705A SaltPro Hand Crank Spreader: a 1.6 liter hopper with a thumb-adjusted gate, per the maker, so you can spread thin. See it on Amazon

Calcium Chloride Pellets Snow and Ice Melter, 50 lb: the listing names Peladow and says it works down to -25°F. For below-15°F days; keep it off concrete under a year old and away from dogs. See it on Amazon

Ice melt FAQ

How much ice melt per square foot?

About 2.3 lb per 1,000 sq ft near freezing, rising to 4.5 lb at 23 to 28°F and 6.8 lb at 15 to 23°F.

How many bags of ice melt for a winter?

Pounds per storm × storms ÷ bag size. 640 sq ft at 25°F for 10 storms is 28.8 lb, one 50 lb bag.

Does more salt melt ice faster?

No. Shovel first and use the chart; leftover salt on dry pavement means you used too much (UW-Green Bay).

More winter math: snow shovels for gravel, electric snow blowers.

Watch Curb Calc on YouTube: youtube.com/@curbcalc

Sources: Dane County rate chart in UW-Green Bay's deicing guide; Rice Creek Watershed District; ASPCA, Jan. 22, 2026; Pennsylvania Aggregates and Concrete Association.