Contents

- 1 How do you calculate concrete for a round hole?
- 2 How much concrete do I need calculator?
- 3 How many bags of concrete do I need for a 4×4 post?
- 4 How many bags of concrete do I need for a 10×20 slab?
- 5 How much concrete do I need for a post hole?
- 6 How many cubic meters is a 25kg bag of concrete?
- 7 How much does 2 yards of concrete cost?
- 8 How many 80lb bags of concrete makes a yard?
- 9 How much concrete do I need for a 10 sonotube?
- 10 What size sonotube for a 4×4 post?
- 11 Is 2 feet deep enough for fence posts?
- 12 Do you need gravel under concrete?
- 13 Do fence posts need concrete?

## How do you calculate concrete for a round hole?

The **formula** for the **volume** of a **round hole** is pi r2 x depth. Or 3.14 x radius x radius x depth. The radius is half the width of the **hole**.

## How much concrete do I need calculator?

For concrete, the formula for volume is as follows: length x width x thickness. To determine how many bags of concrete you will need, divide the total cubic yards needed by the yield. Use the following yields per each bag size: **40 pound** bag yields.011 cubic yards.

## How many bags of concrete do I need for a 4×4 post?

Mix two 50lb **bags of concrete** with water in a mixing tub or 5-gallon bucket. Add **concrete** into the hole and around the 4” x 4”. Depending on your climate, let **concrete** set up for 24 – 48 hours.

## How many bags of concrete do I need for a 10×20 slab?

A 60-pound **bag** yields. 017 cubic yards, and an 80-pound **bag** yields. 022 cubic yards. For a 10 x 10 **slab**, you **would need** 77 60-pound **bags** or 60 80-pound **bags**.

## How much concrete do I need for a post hole?

Remember, the depth of the **post hole should** be one-half of the above-ground **post** height. (Example: For a 6 feet above ground **post**, use a **post** with an overall height of 9 feet and place 3 feet in the ground). The **calculator** will indicate the number of 50 lb. bags of QUIKRETE® Fast-Setting **Concrete** you **need**.

## How many cubic meters is a 25kg bag of concrete?

**Concrete** is a mix, typically of 1 part **cement** to 4-5 aggregate, and a **cubic metre** of finished **concrete** weighs around 2.5 tonnes, so requires around 500kg **cement** or 20× **25kg bags**. In direct answer, there is about 1/100th or 0.01 **m3** in a **25kg bag**.

## How much does 2 yards of concrete cost?

According to the NRMCA – Ready Mixed **Concrete** Industry Data Survey, the **average cost** of **concrete** in 2018 was $120 per cubic yard, or $240 for the **2** cubic **yards** needed for a typical 10-by-10-foot patio.

Bulk **Concrete Prices**.

Cubic Yards |
Price Range |
---|---|

1* | $140-$200 |

2* |
$280-$400 |

3* | $420-$600 |

4* | $560-$800 |

## How many 80lb bags of concrete makes a yard?

If you’re using **80lb bags of concrete**, you’ll need 45 **bags** to **make a yard**.

## How much concrete do I need for a 10 sonotube?

For example, a **sono tube** with a **10**” diameter and a 4′ depth requires 0.08 cubic yards of **concrete**.

## What size sonotube for a 4×4 post?

What **size Sonotube** do I need for a **4×4**” **fence post**? The rule-of-thumb is to use a tube diameter 3 times the **post** width, therefore use a 12” diameter **Sonotube for a 4×4**” **post**.

## Is 2 feet deep enough for fence posts?

Project Instructions

The **depth** of the hole should be 1/3-1/**2** the **post** height above ground (i.e., a 6-foot tall **fence** would require a hole **depth** of at least **2 feet**).

## Do you need gravel under concrete?

Whether **you** pour **concrete** for a walkway or patio, a strong **gravel** base is required to prevent the **concrete** from cracking and shifting. **Gravel** is especially important in clay soil because it doesn’t drain well, which results in water pooling **under** the **concrete slab** and slowly eroding the soil as it finally drains.

## Do fence posts need concrete?

**Concrete** is the most secure material for setting **fence posts**, especially if you **have** sandy soil. Gravel may be okay with dense, clay-heavy soil, but in looser soil, **concrete** is the only thing that will truly keep your **fence posts** stuck in place.