Are you getting ready to build a deck, sidewalk, patio, or BBQ pit? Need to figure out how many bags of concrete for post holes or sonotube footings? Depending on how big your project and where it’s located, it may be easier and cheaper to mix your own than order ready-mix. So, if you’re trying to figure out how many bags of concrete in a yard for your project, this guide is for you.
To mix a yard of 4000psi concrete you’ll need ninety 40lb, seventy-two 50lb, sixty 60lb, forty-five 80lb, or forty 90lb bags of mix. A dry yard of concrete weighs about 3600lbs and needs 32 to 34 gallons of water. A yard of concrete will make a 4” thick, 81ft² slab.
In this guide, we’ll discuss how many square feet are in a yard of concrete, different weights of bagged concrete, cubic feet per bag, the number of bags that make up a yard, and how many bags on a pallet. We’ll also explain how to calculate the amount of concrete you’ll need for a slab, fence post, or sonotube, plus what the dry weight of a yard runs. This is the ultimate guide for deciding whether ready-mix or bagged concrete is best for your project.
- How Many Square Feet Are in a Yard of Concrete
- How Many Cubic Feet in a Bag of Concrete
- How Many Bags of Concrete in a Yard
- How Many 60 Pound Bags of Concrete Make a Yard
- How Many 80lb Bags of Concrete in a Yard
- How Many 40 Pound Bags of Concrete in a Yard
- How Many 50lb Bags of Concrete in a Yard
- How Many Bags of Concrete on a Pallet
- How Much Does 1 Yard of Concrete Cover
- How Many Bags of Concrete Do I Need
- How Much Does a Yard of Concrete Weigh
- How Many Yards of Concrete in a Truck
How Many Square Feet Are in a Yard of Concrete
A yard of concrete is a 3-dimensional measurement that is 3’x3’x3’. If you multiply 3 x 3 x 3 it equals 27. That means a yard of concrete contains 27 cubic feet (1’x1’x1’ or 12”x12”x12”) of concrete.
For our metric friends, a meter of concrete is different from a yard. A meter is 3.28 feet, so a cubic meter is 3.28’x3.28’x3.28’ or 35.29 cubic feet. That’s 8.29ft³ more concrete or almost a third of a yard larger!
How Many Cubic Feet in a Bag of Concrete
The size or weight of a bag or container of concrete determines its volume or cubic measurement. Smaller volumes are commonly used for repairs or crafts, while larger bags are more project-oriented.
Bags of concrete contain cement, sand, and stone or gravel. The ratio of each affects the weight and coverage, as does the thickness. The table below gives the cubic foot measurement of some of the commonly available weights of concrete.
|How Many Cubic Feet in a Bag of Concrete|
|Bag Size||Cubic Feet per bag||Bags per ft³||1” Thick Coverage/bag|
How Many Bags of Concrete in a Yard
The number of bags of concrete mix required to make a yard of concrete depends on the size of the bags being used. The table below identifies how many bags of each size make a cubic yard or 27ft³ of concrete.
It should be noted that whole bags would be used, so round up for the whole bag count. To arrive at the amount, divide the cubic footage required by the amount one bag contains. For example, a cubic yard or 27ft³ ÷ 0.45ft³ (volume of a 60lbs bag) = 60 bags.
|How Many Bags of Dry Mix Concrete in a Yard|
How Many 60 Pound Bags of Concrete Make a Yard
60-pound bags of concrete mix are a common weight for DIY concrete projects. Each bag will do 0.45ft³ and cover 5.4ft² to a thickness of 1-inch or 1.35ft² to a thickness of 4-inches. Sixty 60lb bags of concrete are needed to make a yard of concrete. The cost per bag of 4000psi concrete is $3.55 currently in my location or $2.84 if you buy 56 or more, so 60 bags for a cubic yard would run $170.40 before taxes and weigh 3,600-pounds.
Pro Note: To calculate the area or square footage a bag will cover, convert the depth of the pour to a fraction or decimal of a foot by dividing it by 12, and divide the bag volume by that decimal or fraction. For example: 4” ÷ 12 = 4/12 or 1/3 or 0.333, a 60-pound bag produces 0.45ft³ ÷ 0.333 = 1.35ft² of 4” thick concrete.
How Many 80lb Bags of Concrete in a Yard
An 80-pound bag of concrete mix isn’t lightweight, which is why they make smaller bags, it also may need to be ordered in. Each sack makes 0.6ft³ and will cover 7.2ft² with a 1” thickness or 1.8ft² to a depth of 4”. A cubic yard is 27ft³ and will require (27ft³ ÷ 0.6ft³/bag) 45 bags of mix.
An 80-pound bag of 4000psi concrete costs $4.78 at one store in my area and you save 10% when you purchase 56 bags or more. Since a cubic yard requires 45 bags, the cost for a cubic yard at that store would be $215.10. At a competitor down the street, the cost is $4.37 a bag or $3.50 if you buy 42 or more, making the cost of 45 bags $157.50 before taxes, a saving of almost 30%, so shop around. The weight of 45 bags would be 3,600-pounds.
How Many 40 Pound Bags of Concrete in a Yard
A 40-pound bag of concrete mix makes 0.3ft³ of concrete which would cover 3.6ft² to a thickness of 1”. A yard of concrete is 27ft³, so 27 ÷ 0.3ft³ = 90 bags. A 40-pound bag of 4000psi concrete mix costs between $2.78 and $2.88 in my area. So, a yard of concrete mix will cost between $250.20 and $ 259.20 before taxes and weigh 3,600-pounds.
How Many 50lb Bags of Concrete in a Yard
A 50-pound bag of mix contains 0.37ft³ of 4000psi concrete and would cover 4.44ft² to a 1” thickness. A cubic yard would require 71.8 or 72 bags at a cost of $3.28 per bag for a before tax cost of $239.44 and weigh 3,650-pounds.
How Many Bags of Concrete on a Pallet
The number of bags on a pallet depends on the weight and size of the items placed, the size of the pallet, and the manufacturer. A full explanation can be found in my article How Many Bags of Concrete on a Pallet. The table below identifies the common number of bags on a pallet.
|How Many Bags of Concrete on a Pallet|
|Bags/Pallet||80||63 or 64||56||40 or 42||35|
How Much Does 1 Yard of Concrete Cover
To determine how much a yard of concrete covers depends on the thickness required. Convert the thickness from inches to feet by dividing it by 12, (3” ÷ 12 = 3/12 or 1/4 or 0.25), and then divide 27ft³ by that value to get the square footage it will cover. The thicker the pour, the fewer square feet of coverage, as can be seen in the table below.
|Number of Square feet in a Cubic Yard of Concrete|
Pro Note: A cubic foot of concrete spread 1-inch thick will cover 12ft², 1/2-inch thick 24ft², 1/3-inch thick 36ft², and 1/4-inch thick 48ft². To determine the coverage a yard will do at those thicknesses, just multiply by 27.
How Many Bags of Concrete Do I Need
When planning a pour, identify the surface area of the project and multiply it by the thickness desired. A 3ft wide sidewalk 20ft long (3×20=60) is 60ft². A common thickness for a sidewalk is 4” which needs to be converted to foot measure, so divide it by 12, (4” ÷ 12 = 4/12 or 1/3 or 0.333). Multiply the surface area by the thickness to identify how much concrete the project will require, so 60ft² x 0.333ft = 19.98ft³ of concrete.
A 10×10 slab may be the dimensions of a patio, the base of a shed, a section of a driveway, or something else. The use of the pad determines the thickness. A patio may only need to be 3” thick if supported by a compacted base. A shed may be 4” or 6” depending on what will be stored on it, and a driveway is commonly between 4” and 6” depending on what will be parked or driven on it.
The surface area is 10’x10’, or 100ft². The thickness of the pour determines how much concrete is needed. Convert the thickness from inch to foot measure by dividing it by 12, (5 ÷ 12 = 0.4167) and multiply it by the area (100 x 0.4167 = 41.67 or 41.7ft³) for the volume of concrete required. The table below identifies how many 60lb or 80lb bags needed for common thicknesses.
|How Many Bags of Concrete for 100 Square Feet|
|60lb Bags: 0.45ft³||56 bags||74 bags||93 bags||112 bags|
|80lb Bags: 0.6ft³||42 bags||56 bags||70 bags||84 bags|
24×24 x4 Slab
A pad of concrete 24’x24’x4” could serve as a patio, garage floor, driveway, floor of a cabin, or another purpose. To determine the amount of concrete, convert the thickness to foot measure by dividing it by 12, (4” ÷ 12 = 0.333) and multiply the dimensions to get the product (24 x 24 x 0.333 = 191.81ft³) or volume of concrete. The slab will require 191.81ft³ or 7.1 yards (191.81 ÷ 27 = 7.1) of concrete. That’s 427 60-pound bags or 320 80-pound bags of concrete, a whopping 25,620-pounds!
The amount of concrete needed per fence post depends on a number of factors. The diameter of the post hole and its depth plus how far above the ground the concrete will rise is one part of the equation. The dimensions of the post and how far it goes into the hole affect the amount of concrete too since it occupies or uses some of the post hole’s volume.
Post holes range from 6” to 18” in diameter, but are commonly double the diameter of the post, or 8” or 12” round for 4×4 or 6×6 posts, respectively. The depth of the hole often depends on soil consistency, what the post supports, plus frost depth. Post holes commonly range from 1-1/2’ (18”) to 4’ (48”) in depth, with the post inserted to be 3” to 6” off the bottom for moisture protection.
To calculate the volume of the hole, multiply the radius (half the diameter) of the hole by itself (r²), then multiply it by the depth of the hole or vertical measure of the concrete, and finish it off by multiplying it by pi (π = 3.14). The formula for the volume of a post hole or cylinder is v = π r²h.
You then must subtract the volume of the post being sunk into the hole, which is the length x width x height (LxWxH) for a milled post. It should be noted that all dimensions are best converted to foot measurements for ease of calculating the amount of concrete required.
For example, an 8” diameter hole has a radius of 4” or 0.333’, if it is 48” or 4’ deep, and using the formula v = π r²h, the volume would be 3.14×0.333²x4 = 1.39ft³. A 4×4 post is actually 3.5”x3.5” or 0.29’x0.29’, and if it is set 45” or 3.75’ deep the volume it displaces is 0.29’x0.29’x3.75’ = 0.315ft³.
Subtract the post volume from the hole volume, and you get the amount of concrete required. So, 1.39ft³ – 0.315ft³ = 1.075ft³ of concrete, or approximately 2.39 or 3, 60lb bags or 1.79 or 2, 90lb bags of concrete mix. If you need a bit more concrete in the hole, add a rock or two to raise the level.
That’s a lot of math, so this table may be helpful.
|Amount of Concrete for Fence Posts
(For posts set 3” off the hole base)
|Post Hole Depth||4×4 Post
8” diameter hole
12” diameter hole
|60lb Bag (0.45ft³)||80lb Bag (0.6ft³)||60lb Bag (0.45ft³)||80lb Bag (0.6ft³)|
|18” or 1.5’||1 bag||1 bag||2 bags||2 bags|
|Volume to fill 0.41575ft³||Volume to fill 0.915ft³|
|24” or 2’||2 bags||1 bag||3 bags||2 bags|
|Volume to fill 0.54725ft³||Volume to fill 1.2025ft³|
|30” or 2.5’||2 bags||2 bags||4 bags||3 bags|
|Volume to fill 0.67875ft³||Volume to fill 1.49ft³|
|36” or 3’||2 bags||2 bags||4 bags||3 bags|
|Volume to fill 0.81025ft³||Volume to fill 1.7775ft³|
|42” or 3.5’||3 bags||2 bags||5 bags||4 bags|
|Volume to fill 0.94175ft³||Volume to fill 2.065ft³|
|48” or 4’||3 bags||2 bags||8 bags||4 bags|
|Volume to fill 1.07325ft³||Volume to fill 2.3525ft³|
Sonotube Deck Footings
Sonotube footings for decks often have a deck anchor inserted into the concrete instead of a portion of the post, so they are fully filled with concrete. Calculate the volume of the sonotube using its radius and length or depth it is sunk into the ground (v = π r²h where pi or π = 3.14). The table below indicates the amount of concrete needed for different diameters of 4-foot sonotube lengths.
|Concrete for Sonotube Deck Footings|
|Sonotube Diameter||Volume||60lb Bag (0.45ft³)||80lb Bag (0.6ft³)|
|8” x 4ft||1.393ft³||3.1 or 4 bags
(or 3 bags and a rock or two)
|2.32 or 3 bags|
|10” x 4ft||2.181ft³||4.84 or 5 bags||3.635 or 4 bags|
|12” x 4ft||3.14ft³||6.98 or 7 bags||5.23 or 6 bags|
How Much Does a Yard of Concrete Weigh
A yard of concrete is composed of cement, sand, and stone or gravel, otherwise known as aggregates. The dry content is bagged and shipped on pallets. Different grades or strengths use different ratios in the blend, resulting in varying weights per yard. The weight of water added is about half the weight of the cement ratio in the mix.
It takes sixty 60lb or forty-five 80lb bags of 4000psi concrete mix to make a yard of concrete. Mathematically, 60×60 = 3600lbs and 45×80 = 3600lbs, so a dry cubic yard of concrete mix would weigh 3600lbs. Adding water to the mix increases the average weight to approximately 4000lbs.
Depending on the manufacturer, the ratio of measures to make the concrete mix, elevations, and temperatures, a yard of concrete may need between 27 and 35 (or more) US-gallons of water. A US gallon of water weighs 8.34lbs, so the number of gallons increases the weight accordingly.
Water is needed for the chemical reaction to harden the powder mix. However, although it doesn’t change the overall finished volume much, it does change the initial weight. As the concrete cures, much of the water evaporates, reducing the weight to approximately 3700lbs.
How Many Yards of Concrete in a Truck
The amount of weight a truck can carry depends on what it is designed to carry. Some factors affecting loads are where it is traveling and when. Hills and bridges can restrict load sizes, and weight limitations may vary between jurisdictions and even seasonally. Additionally, statutory US weight limits of 80,000 pounds on tractor-trailers restrict loads to between 43,000 and 47,000 pounds, as do 48,000 pounds on 3-axle cement trucks.
On average most ready-mix concrete trucks carry 10.5 yards or 42,000 pounds, although some carry 12.5 yards. A 48’ tractor-trailer often carries 14 yards, delivery trucks 2 to 3 yards, and a half-ton truck about a third of a yard of dry mix.
To determine your vehicle’s carrying capacity, identify the GVWR and subtract its curb weight. A 1/2-ton truck with a 6600lb GVWR and a curb weight of 5100lbs, has a load capacity of 1500lbs, including the driver, passengers, and cargo. It isn’t recommended to exceed the load capacity.