Concrete Resurfacer Calculator

1. Enter the length and width of the slab to resurface.
2. Enter the coat thickness in inches. A skim coat is about 1/16 inch; repairs go thicker.
3. Enter the bag yield from your product. The default suits a 40 pound bag.
4. Read the bags needed, rounded up, with the coverage one bag gives at your thickness.

Here is what each result line means:

A concrete resurfacer calculator tells you how many bags of resurfacer to buy to renew a worn, pitted or stained slab. Resurfacer is a cement-based coating you spread thin over sound concrete to give it a fresh, even surface.

It is applied in a thin coat, often with a squeegee or broom, so coverage depends heavily on the thickness. The tool turns your area and thickness into a volume and divides by the yield of one bag. To seal the surface afterwards, use the concrete sealer calculator.

The volume is the area times the coat thickness in feet. Dividing by the yield of one bag gives the bag count, and a waste allowance covers a rough surface and overlap.

1. Multiply length by width for the slab area.
2. Multiply by the thickness in feet (inches divided by 12) to get the volume.
3. Divide the volume by the yield of one bag.
4. Add the waste allowance and round up to whole bags.

Thickness is the input that moves the count most. A 1/16 inch skim coat covers far more per bag than a 1/4 inch repair, so measure the coat you actually plan to apply.

Suppose you are resurfacing a 16 by 24 foot driveway, 384 square feet, with a thin 1/16 inch skim coat, a bag that yields 0.34 cubic feet, and a 10 percent waste allowance.

Calculation: the volume is 384 times 0.0625 divided by 12, which is 2 cubic feet. Divided by 0.34 that is 5.9 bags, and adding 10 percent gives about 6.5, so you round up to 7 bags. At 1/16 inch, one bag covers about 65 square feet.

The lesson: a thin skim coat stretches a long way, but a thicker repair coat uses bags fast, so the thickness you choose drives the order.

Coat Thickness

This has the biggest effect. At 1/16 inch a 40 pound bag covers around 65 square feet, but only about 16 at 1/4 inch, so a thicker coat multiplies the bag count.

Surface Roughness

A rough, pitted or spalled surface swallows more resurfacer than a smooth one, because it fills the low areas first. Add more waste for a rough slab.

Bag Yield

Yield varies by product and bag weight. A 40 pound bag is around 0.34 cubic feet; check the coverage on your bag and adjust the input.

Overlap and Wet Edge

You lose a little to overlap and to keeping a wet edge as you work. A 10 percent allowance, plus a spare bag, keeps the job moving.

Resurfacer is one of several thin cement coatings, and they are used for different jobs.

Resurfacer renews a surface rather than leveling it. If the slab is badly out of level, a self-leveler is the right product; if it is cracked through or heaving, it may need replacing.

Renewing a Driveway or Patio

Estimate the bags to recoat a worn but structurally sound slab.

Prepping for a Finish

Work out a skim coat before a coating, stain or sealer goes on.

Comparing Products

See how a thin skim coat and a thicker repair coat differ in bags and cost for the same slab.

1. Using Too High a Coverage Figure

Marketing numbers can overstate coverage. Use the data-sheet figure for your thickness, and the low end for a rough surface.

2. Ignoring Thickness

Coverage falls fast as the coat gets thicker. A 1/4 inch coat uses roughly four times the bags of a 1/16 inch skim.

3. Resurfacing Unsound Concrete

Resurfacer renews a surface; it does not fix a slab that is cracked through, heaving or crumbling. Those need repair or replacement first.

4. Running Short Mid-coat

You need to keep a wet edge, so stopping to buy more leaves a visible line. Keep a spare bag on hand.

5. Skipping Surface Prep

Resurfacer bonds to clean, sound, dampened concrete. Dirt, sealer or loose material causes it to peel.

The math is exact for the thickness and yield you enter, but real surfaces are rough and products differ, so treat the result as a planning estimate and buy a little extra.

Multiply the slab area by the coat thickness in feet to get a volume, then divide by the yield of one bag and add about 10 percent. A 384 square foot driveway at a 1/16 inch skim coat, with a 0.34 cubic foot bag, needs about 7 forty-pound bags.

It depends on thickness. A 40 pound bag yielding about 0.34 cubic feet covers roughly 65 square feet at 1/16 inch, or about 16 square feet at 1/4 inch. Coverage falls as the coat gets thicker, so check your bag.

A broom or squeegee skim coat is about 1/16 inch. Repairs and heavier coats go thicker, up to about 1/2 inch depending on the product. Thin, even coats bond and cure better than one heavy pass.

No. Resurfacer renews a worn surface in a thin coat; self-leveler flows out to flatten an uneven floor at a greater depth. If your slab is out of level rather than just worn, use a self-leveler.

Only if the slab is structurally sound. Resurfacer renews the surface but does not fix concrete that is cracked through, heaving or crumbling. Those problems need repair or replacement first.

Yes. Resurfacer bonds to clean, sound, dampened concrete. Remove dirt, old sealer and loose material, and follow the product prep steps, or the coating can peel.

Yes. You need to keep a wet edge as you work, so running short leaves a visible line. Keep a spare bag beyond the calculated amount, which is why the tool adds a waste allowance.

The arithmetic is exact for your inputs. The uncertainty is in the coat thickness and the product coverage, which vary with the surface, so measure the coat you plan and use your bag yield.

No. The calculation runs entirely in your browser and nothing you enter is stored or sent anywhere.

• Quikrete Re-Cap Concrete Resurfacer data sheet (40 lb bag covers ~65 sq ft at 1/16 in, ~16 sq ft at 1/4 in).
• Quikrete Concrete Resurfacer product page (product overview and application).
• American Concrete Institute (ACI; concrete repair and surface coatings).