Sakrete Bag Calculator
How many bags of Sakrete does a 10 x 10 ft patio slab actually take? At 4 inches thick with 80 lb bags the answer is 56 bags, or 62 once this calculator adds its 10 percent waste allowance. The Sakrete bag calculator below works for rectangular slabs and round post holes in 40, 60, 80 and 90 lb bags of Sakrete High-Strength Concrete Mix, and it returns the bag count with the water, the total haul weight and the material cost for the job. Calculator Zilo is not affiliated with or endorsed by Sakrete: the yields and water amounts are Sakrete’s own published figures for that mix, checked against the current data sheet for this rewrite.
Yields and water amounts are Sakrete’s published specs for High-Strength Concrete Mix, from the current data sheet; field yield varies with water content and placement. Add water gradually: excess water weakens the concrete. This page is an independent estimator and is not affiliated with Sakrete.
Quick Answer
A 10 x 10 ft slab, 4 inches thick, in 80 lb bags at $6.50 a bag needs 56 bags of Sakrete High-Strength Concrete Mix, and this calculator recommends 62 bags with its 10 percent waste allowance: 33.33 cu ft of concrete, 4,960 lbs to haul, 217 quarts (54.3 gallons) of mixing water and $403.00 of material. Those are the pre-filled values above, so one click on Calculate reproduces every figure.
- Quick Answer
- How to use the Sakrete bag calculator
- Sakrete yield and water per bag, from the current data sheet
- Worked example: the 10 x 10 patio slab, checked against this tool
- Post holes: the fence-post math
- Which Sakrete mix, and how thick
- What competing calculators miss
- Frequently asked questions
- Add This Calculator to Your Website
- References
How to use the Sakrete bag calculator
Set the shape and the bag size, type the dimensions, and click Calculate. The results stay hidden until a run succeeds, and the price field is the only optional one.
- Pick the project shape: Rectangular slab, or Round post hole(s). Switching to holes renames the fields to diameter and depth, hides the width field, shows the hole count, and clears any results on screen.
- Pick the bag size: 40, 60, 80 or 90 lb. The yield printed next to each size is the one the math uses.
- Enter the dimensions: slab length and width in feet with thickness in inches, or hole diameter and depth in inches with the number of holes.
- Add a price per bag if you want the cost line: leave it blank and no cost appears.
- Set the waste allowance to match the job: it starts at 10 percent, which covers a typical slab; use about 5 percent for small, well-formed post holes and about 15 percent for rough or hand-dug work.
- Click Calculate bags: you get the project volume, the exact bag count, the recommended count with your chosen waste allowance, the total weight to haul, the water in quarts and gallons, and the cost when a price was entered, with the formula printed under the result.
Bad entries are rejected one at a time, in field order, with plain messages: “Enter the slab length in feet.”, “Slab thickness must be greater than zero.”, “Number of holes must be at least 1.” and, checked last, “Price per bag cannot be negative.” Two honest behaviours to know: the hole count is read as a number, not rounded, so 2.5 holes computes a volume (round your count up yourself), and the price is only validated after the dimensions pass, so a dimensions error shows first.
Sakrete yield and water per bag, from the current data sheet
Every bag count here comes from Sakrete’s published yield for High-Strength Concrete Mix, and every water total from the same data sheet’s starting water amounts. Here is the whole table the calculator runs on:
| Bag size | Yield per bag | Water per bag (starting amount) | Bags per cubic yard |
|---|---|---|---|
| 40 lb | 0.30 cu ft | 1.75 quarts | 90 |
| 60 lb | 0.45 cu ft | 2.5 quarts | 60 |
| 80 lb | 0.60 cu ft | 3.5 quarts | 45 |
| 90 lb | 0.66 cu ft | 4.5 quarts | 41 |
The water column is a starting reference, which is how Sakrete’s High-Strength Concrete Mix data sheet presents it: more may be needed to reach a workable consistency, and overwatering is the mistake to avoid, because every extra quart raises the water-cement ratio and lowers the finished strength. The same sheet sets the strength figures used across this page: 2,500 psi at 7 days and 4,000 psi at 28 days, meeting ASTM C387.
One transparency note. Older Sakrete data sheets, still mirrored on retailer and calculator sites, list 2, 3 and 4 quarts of water for the 40, 60 and 80 lb bags and a 0.68 cu ft yield for the 90 lb bag, and the previous version of this calculator ran on those older numbers. This rewrite follows the current data sheet, so water totals here run lower than the old page’s, and 90 lb bag counts run slightly higher. If a store’s shelf card disagrees with this table, the data sheet for the bags in front of you wins. One split remains inside Sakrete’s own current documents for the 90 lb size: the specification sheet lists its starting water as 4.25 qt, while the technical data sheet and the installation guide say 4.5 qt, and this calculator follows the 4.5 qt figure.
60 lb bags: the solo-worker choice
- Fits a wheelbarrow batch comfortably and carries without a second pair of hands.
- Costs you more trips: the worked slab takes 83 bags recommended, against 62 at 80 lb.
- Same concrete, same 0.45 cu ft yield math, just a smaller package.
80 lb bags: the value choice
- Fewest bags per cubic foot of the common sizes, and usually the lowest cost per cubic foot.
- Each bag is a genuine 80 lb lift, awkward on stairs, ladders and long carries.
- A standard mixer tops out at two 80 lb bags per batch, per Sakrete’s own mixing guide.
Worked example: the 10 x 10 patio slab, checked against this tool
The pre-filled example is the standard patio pour: 10 ft by 10 ft at 4 inches thick, 80 lb bags at $6.50. The calculator returns 56 bags, 62 recommended, and the step-through below is exactly its arithmetic.
Four more runs of the same tool, covering the other bag sizes and the post-hole mode, so you can check the calculator against your own job before you trust it:
| Run | Volume | Bags / recommended | Weight | Water | Cost |
|---|---|---|---|---|---|
| Slab 10 x 10 x 4 in, 40 lb, $6.50 | 33.33 cu ft | 112 / 124 | 4,960 lbs | 217 quarts (54.3 gal) | $806.00 |
| Slab 10 x 10 x 4 in, 90 lb, $7.25 | 33.33 cu ft | 51 / 57 | 5,130 lbs | 256.5 quarts (64.1 gal) | $413.25 |
| 1 post hole, 12 in dia x 36 in, 60 lb | 2.36 cu ft | 6 / 7 | 420 lbs | 17.5 quarts (4.4 gal) | no price entered |
| 8 post holes, 12 in dia x 36 in, 60 lb | 18.85 cu ft | 42 / 47 | 2,820 lbs | 117.5 quarts (29.4 gal) | no price entered |
Read the weight column before you read the cost column. Even the lightest version of the patio slab puts 4,960 lbs, about two and a half tons, on the shopping list, and that decides the vehicle, the number of trips and whether delivery beats the store run, long before the $403.00 does.
A second slab check, from the older Sakrete page, re-run through this tool: a 10 ft by 4 ft slab at 6 inches thick in 60 lb bags holds 10 x 4 x (6 / 12) = 20.00 cu ft. That is 20.00 / 0.45 = 44.44, rounded up to 45 bags exact, and this calculator recommends 50 bags with its 10 percent waste allowance (45 x 1.10 = 49.5, rounded up to 50), weighing 3,000 lbs with 125 quarts (31.3 gallons) of water. Note the waste method: this calculator applies the 10 percent to the rounded bag count, so its recommended figure can differ by one bag from a volume-first waste calculation on the same job. The four post holes in the older example check the same way: each 12 inch diameter hole 36 inches deep holds 2.36 cu ft, four holes hold 9.42 cu ft, and this tool gives 21 bags exact and 24 recommended.
On waste percentages: the waste allowance is adjustable and starts at 10 percent, which covers a typical slab. Use about 5 percent for small, well-formed post holes and about 15 percent for rough or hand-dug work. From the exact count this tool prints, those are ceiling of exact x 1.05 and ceiling of exact x 1.15. On the 10 x 4 ft slab above, exact 45 bags gives 48 bags at 5 percent and 52 bags at 15 percent; set the waste allowance to 5 or 15 percent and the tool reproduces them.
Post holes: the fence-post math
Bagged concrete’s most common job is setting posts, and the hole mode of this calculator exists because the volume formula changes: a round hole holds pi × radius² × depth, not length × width × thickness. Sakrete’s data sheet gives the digging rules that go with it: the hole should be about one third as deep as the post is long and about three times as wide as the post, with 3 to 4 inches of gravel at the bottom for drainage, the concrete sloped at the surface so water drains away, and at least 24 hours before the post takes any strain. Load-bearing posts also need a check against local code.
A 12 inch diameter hole, 36 inches deep, holds 2.36 cu ft, which the checks table above turns into 6 bags of 60 lb mix per hole, 7 with waste. Two things the tool does not do, stated plainly: it fills the whole hole and does not subtract the volume the post itself occupies, so every hole count carries a small built-in cushion on top of the waste allowance; and it prices the concrete only, so when you are budgeting the full run, posts, rails and hardware belong in a fence price calculator alongside this page’s bag count.
Which Sakrete mix, and how thick
The yields in this table belong to one product, Sakrete High-Strength Concrete Mix, and the bag you actually buy has to match the table. High-Strength is the general-purpose choice for placements 2 inches thick and up: driveways, slabs, patios, walkways, curbs, stairs, ramps, footings, foundation walls and posts, per Sakrete’s own application list in Sakrete’s concrete slab project guide. Working thicknesses: 4 inches is the practical minimum for patios and walkways, and driveways want 5 to 6 inches, especially under heavier vehicles.
Two neighbouring Sakrete products are deliberately not in this calculator. Fast-Setting mix trades working time for a set measured in minutes on post jobs, and Maximizer is a high-yield lightweight mix whose 80 lb bag yields about 0.92 cu ft at 5,500 psi: on the worked slab that is 37 bags, not 56, so running Maximizer through this page would have you hauling home roughly half as many bags again as you need. If your job is 80 lb High-Strength bags and nothing else, the dedicated 80 lb Sakrete calculator covers that single size in depth; this page is the broader tool for choosing between all four bag sizes. And when a pour outgrows bags altogether, past roughly a cubic yard the honest answer is ready-mix: get the volume from a concrete volume calculator and the pad dimensions from a concrete area calculator, and price the truck against 45-plus bags you would otherwise mix by hand.
Whichever mix you pour, curing decides whether it reaches its rated strength. Sakrete’s placement guidance is to keep the surface damp for several days (sprinkler, wet burlap or plastic sheeting), protect fresh concrete from freezing for at least the first 24 hours in cold weather, and let the strength clock run: foot traffic at about 24 hours, vehicles after at least 72 hours, full 4,000 psi at 28 days. The mixing technique matters just as much: Sakrete’s hand-mixing guide works one 80 lb bag at a time in a wheelbarrow with about three quarters of the water in first, and its mixer guide caps a standard mixer at two 80 lb bags per batch.
What competing calculators miss
Bag calculators are plentiful; Sakrete-specific ones that show their data are not:
- Sage Calculator’s Sakrete page: slab framing only, with the depth entered in feet (their worked example uses 0.5 ft), which invites unit slips on the most common input. No post-hole mode, no water, no weight, no cost.
- CalculatorsHub’s Sakrete slab page: a formula error worth naming. Its worked example divides 10 × 8 × 6 (inches, unconverted) by a “coverage” of 12 to claim 40 bags. A 10 x 8 ft slab at 6 inches is 40 cu ft, which is 89 bags of 60 lb mix at 0.45 cu ft per bag. The rival’s answer is less than half the concrete the slab holds.
- Aqua-Calc’s slab calculator: the strongest general rival, with volumes in three unit systems and a full bag-size table built on Quikrete and Sakrete specs blended together. It stops at the count: no Sakrete water amounts, no post holes, and no cost for the one bag size you actually chose.
- DIY Concrete Calculator: a genuinely useful bag-size comparison with ready-mix threshold advice, but brand-generic (Quikrete and Sakrete treated as interchangeable), slab shapes only, and no water specification at all.
- Sakrete’s own app: augmented-reality measuring and product matching are excellent on a phone at the store, but the numbers live inside the app. There is no on-page yield and water table to audit before you buy, which is the whole job of this page.
- The gap this page fills: current Sakrete data-sheet yields and water, slab and post-hole modes in one tool, haul weight and optional cost on every run, and worked checks, including the rival error above, that you can retype and verify.
Frequently asked questions
At 4 inches thick the slab holds 33.33 cu ft. In 80 lb bags (0.60 cu ft each) that is 56 bags, and the calculator recommends 62 with its 10 percent waste allowance. Enter 10, 10 and 4 with the 80 lb bag selected to reproduce it.
One 80 lb bag of Sakrete High-Strength Concrete Mix yields about 0.60 cu ft of finished concrete, per Sakrete’s data sheet. That works out to 45 bags to the cubic yard before any waste allowance.
Per Sakrete’s current data sheet, start with 1.75 quarts for a 40 lb bag, 2.5 quarts for a 60 lb bag, 3.5 quarts for an 80 lb bag and 4.5 quarts for a 90 lb bag. Add the water gradually and only up to the consistency you need: excess water weakens the finished concrete.
A cubic yard is 27 cu ft. At 0.45 cu ft per bag, 60 lb bags take exactly 60 bags per cubic yard. The same math gives 90 bags at 40 lb, 45 bags at 80 lb and 41 bags at 90 lb (0.66 cu ft per bag), all before any waste allowance.
The concrete inside is the same High-Strength mix; only the bag changes. The 80 lb bags mean fewer bags to mix and usually a lower cost per cubic foot, but each one is a heavy lift. If you are working alone, carrying bags any distance, or mixing one bag at a time in a wheelbarrow, the 60 lb bags are the kinder choice.
Sakrete’s data sheet guidance is a hole about one third as deep as the post is long, and about three times as wide as the post or pole. Put 3 to 4 inches of gravel in the bottom for drainage, slope the concrete at the top so water drains away from the post, and wait at least 24 hours before putting any strain on it.
Yes. Sakrete’s slab guide mixes one 80 lb bag at a time in a wheelbarrow, adding about three quarters of the water first and the rest while mixing for roughly three minutes. A rotary mixer handles up to two 80 lb bags per batch. Once a job runs past a dozen or so bags, rent the mixer.
Sakrete rates High-Strength Concrete Mix as open to foot traffic in 24 hours, at 2,500 psi after 7 days and at its full 4,000 psi after 28 days. Give vehicle traffic at least 72 hours, and keep the surface damp for several days while the concrete cures.
No. This calculator uses the yields and water amounts for Sakrete High-Strength Concrete Mix only. Maximizer is a different mix: an 80 lb bag yields about 0.92 cu ft, so running it here would overstate the bag count badly. Check the data sheet for the exact mix you bought before relying on any bag count.
Initial set is typically around 30 minutes. Keep the surface damp while it cures: Sakrete rates this mix as open to foot traffic in 24 hours, at 2,500 psi after 7 days and at its full 4,000 psi after 28 days. Give vehicle traffic at least 72 hours.
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References
- Sakrete (data sheet hosted by Angelus Block). Sakrete High-Strength Concrete Mix Data Sheet (yields and water for all four bag sizes, ASTM C387, 2,500 psi at 7 days and 4,000 psi at 28 days, and the post-hole digging rules). Accessed October 24, 2026.
- Sakrete (specification sheet hosted by Unilog). High-Strength Concrete Mix Specification Sheet (independent Sakrete sheet confirming the same yields and starting water amounts, and foot traffic at 24 hours). Accessed October 24, 2026.
- Sakrete. Pro Tips: How to Pour a Concrete Slab (mixing order, the 3.5 quart water call for an 80 lb bag of High-Strength, and slab placement technique). Accessed October 24, 2026.
- Sakrete. Mixing Concrete by Hand (one 80 lb bag per wheelbarrow batch, three minutes of mixing, and the one-hour placement window). Accessed October 24, 2026.
- Sakrete. Mixing Concrete Using a Mixer (two 80 lb bags per mixer batch and the head-water technique). Accessed October 24, 2026.
- Sakrete (data sheet hosted by Angelus Block). Sakrete Maximizer Concrete Mix Data Sheet (Maximizer yields and strengths, the source for the 0.92 cu ft and 5,500 psi figures quoted for contrast). Accessed October 24, 2026.