Concrete countertop calculator
Add each countertop piece, its thickness and any cutouts to see how many bags of mix to buy and how much the finished top will weigh.
Enter your measurements
More options: Extra
- Countertop area
- 21.3 sq ft
- Mix needed (incl. extra)
- 3.05 cu ft (0.11 cu yd)
- Finished weight (about 140 lb per cu ft)
- 372 lb (0 tons)
- Weight per square foot
- 17.5 lb
120 in × 25.5 in = 21.3 sq ft
21.3 sq ft × 1.5 in = 2.66 cu ft + 15% = 3.05 cu ft
÷ 0.6 cu ft per 80 lb bag = 6 bags
- Most countertop cabinets carry a concrete top, but check long overhangs, islands and old or frameless cabinets — and plan how you will lift a precast piece into place.
Quick answers for common sizes
| Example | Answer |
|---|---|
| How many bags of concrete for a countertop | 6 bags of 80 lb mix for a 10 ft run, 1½ in thick |
Your countertop at other thicknesses
| Thickness | Countertop mix bags | Finished weight (about 140 lb per cu ft) | Mix needed (incl. extra) |
|---|---|---|---|
| 1.5 in | 6 bags | 372 lb | 3.05 cu ft |
| 2 in | 7 bags | 496 lb | 4.07 cu ft |
| 2.5 in | 9 bags | 620 lb | 5.09 cu ft |
| 3 in | 11 bags | 744 lb | 6.11 cu ft |
A countertop is a thin slab: area × thickness, minus any sink or cooktop cutouts. Quikrete’s Countertop Mix data sheet gives each 80 lb bag about 0.6 cu ft, the same yield as its standard concrete mix but with finer aggregate and higher strength (6,000 psi at 28 days on the data sheet).
area (sq ft) = length (in) × depth (in) ÷ 144, for each piece mix (cu ft) = (area − cutouts) × thickness (in) ÷ 12 × (1 + extra) bags = mix ÷ bag yield
| Thickness | Sq ft per 80 lb bag | Weight per sq ft |
|---|---|---|
| 1½ in | 4.8 | 17.5 lb |
| 2 in | 3.6 | 23.3 lb |
| 2½ in | 2.9 | 29.2 lb |
| 3 in | 2.4 | 35 lb |
A full kitchen run is worked through on how many bags of concrete for a countertop.
Cast in place or precast?
Cast-in-place tops are formed right on the cabinets, so there are no heavy pieces to move, but the finishing happens in your kitchen. Precast tops are cast upside down in a melamine form on a bench, which gives the smoothest face, then lifted into place — a 10 ft piece at 1½ in weighs well over 300 lb. Break long runs into pieces two or three people can carry.
Tips
- Reinforcement matters more in a thin slab than a thick one. Follow the mix maker’s guidance on mesh, rebar or fibers.
- Mix all the bags for one piece to the same water content, or the colour will vary across the top.
- Seal the top with a sealer made for countertops and food contact, and reapply as its label says — see the sealer calculator.
What you’ll need
- Concrete countertop mixMid-range price
A fine, high-strength mix made for thin, flat pieces with crisp edges. Check its yield on the bag.
See options on Amazon (opens in a new tab) - Concrete countertop sealerMid-range price
Protects a countertop from stains and acids. Read the label for food-contact use and recoat timing.
See options on Amazon (opens in a new tab) - Drill mixing paddleBudget price
Mixes mortar, self-leveler, stucco and grout in a bucket. Use a low-speed, high-torque drill so the mix doesn’t fly.
See options on Amazon (opens in a new tab) - Steel finishing trowelBudget price
For a smooth, dense finish on slabs, steps and countertops, and for stucco finish coats.
See options on Amazon (opens in a new tab)
As an Amazon Associate we earn from qualifying purchases. Links to products are affiliate links — they cost you nothing extra and help keep these calculators free.
Frequently asked questions
How much does a concrete countertop weigh per square foot?
About 17.5 lb per sq ft at 1½ in thick and 23 lb at 2 in, at roughly 140 lb per cu ft. A 25 sq ft kitchen top at 1½ in is about 440 lb.
How thick should a concrete countertop be?
Many DIY tops are 1½–2 in thick; thinner pieces use glass-fiber-reinforced mixes. Follow the guidance for the mix and reinforcement you use.
Can I use regular concrete mix for a countertop?
You can, but general mixes have larger stones that make thin edges and a smooth face harder. A countertop mix yields the same per bag and finishes better.
Sources
- Quikrete Countertop Mix (No. 1106) data sheet (opens in a new tab) — Each 80 lb bag yields about 0.6 cu ft; 2,000 psi at 24 hours, 4,000 at 7 days, 6,000 at 28 days.
- Quikrete Concrete Mix (No. 1101) data sheet (opens in a new tab) — Yields: 40 lb ≈ 0.30, 50 lb ≈ 0.375, 60 lb ≈ 0.45, 80 lb ≈ 0.60, 90 lb ≈ 0.675 cu ft; unit weight ≈ 140 lb/cu ft; for pours 2 in thick or more; 6–9 pints of water per 80 lb bag; control joints every 6–8 ft; cure 5 days at 70 °F or above, 7 days at 50–70 °F; protect from freezing for 48 hours.