The number of deck posts you need depends on the size and design of your deck, as well as local building codes. Generally, you should have a deck post at each corner of your deck and additional posts spaced no more than 6 to 8 feet apart along the perimeter and under load-bearing points like beams and joists.

- 10×10 deck: You will need 4 to 6 posts, depending on the local codes and your choice of materials.
- 12×12 deck: You will need 5 to 7 posts.
- 16×20 deck: You will need 7 to 10 posts.
- 16×16 deck: You will need 7 to 10 posts as well.

Deck is the outdoor construction. It may be attached to your house, or floating deck in your yard. It is good looking and increases the aesthetic space and beauty of your house. Adding a deck to a house or yard is a great way to create an outdoor living space. Building a deck requires plenty of planning as well as the right materials joists, posts, footing, subfloor, and methods, but it’s worth the effort.

One of the common and most important materials required as vertical members for deck are Posts that transfer all incoming loads from subfloor to soil via footings. How many deck posts do i need will depend on size and shape of your deck, local building code, size of posts, distance between two post, loads of subfloor, attached or floating deck and design of your deck.

A floating deck is a structure that is not attached to your house or another existing building. It is self-supporting structure and are not connected to your home’s existing foundation. This will require more posts for design structure. An attached deck is connected to some existing structure, such as your house, garage, or other building. This will require fewer footings and posts.

Size of posts which are used for deck is 4×4, or 6×6. If you use 4 inches by 4 inches posts, you will need more posts while using 6″×6″ will require fewer number of posts. Diameter of footing should be range between 8 to 24 inches for round footing. If you use square footing, then best size are 16″×16″, 18″×18″, or 20″×20″.

What will be best distance between two posts for my deck. Even if your deck is simple, posts should be always placed at a distance of not more than 8 foot center to center apart. More load on subfloor and other heavy objects will require additional post and larger deck beams. After completing the design of the deck, you can calculate how many posts you will need.

**How to figure how many posts do i need**

To figure the number of posts you will need for any deck, count the post that installed at each of the corners, and a line post needs to be placed between each pair of corner posts at distance less than an 8 foot apart. That makes a total of 8 posts that need to be installed on this average size deck and plus atleast 2 posts more if you are planning on building stairs.

How many deck posts do I need for our deck will depend on size and shape your deck, size of footing and size of beams. The larger the beam and footing size, the fewer posts are required.

**How many posts do i need for a 8×12 deck**

If your deck is 8×12 foot with posts which spaced 4 feet apart in shorter side (8-foot side) and 6 feet apart in longer side (12-foot side) on center will require 8 posts, plus atleast 2 posts more if you are planning on building stairs. The attached 8’×12′ deck will need 3 posts plus atleast 2 more for stairs.

A deck that is 8×12 or 8′ by 12′ will need a post installed at each of the corners. This makes total 4 posts placed at corner. The shorter side the 8-foot side—will have 4-feet of distance between deck posts. The larger 12-foot side will have a post spacing of 6 feet at a minimum code requirement. This makes total 4 posts placed at line post. Add both figure that makes a total of eight posts that need to be installed on 8×12 size deck.

**How many posts do i need for a 10×10 deck**

If your deck is 10×10 foot with posts which spaced 5 feet apart each side on center will require 8 posts, plus atleast 2 posts more if you are planning on building stairs. The attached 10’×10′ deck will need 3 posts plus atleast 2 more for stairs.

A deck that is 10×10 or 10′ by 10′ will need a post installed at each of the corners. This makes total 4 posts placed at corner. The each side the 10-foot side—will have 5-feet of distance between deck posts. This makes total 4 posts placed at line post. Add both figure that makes a total of eight posts that need to be installed on 10×10 size deck.

**How many posts do i need for a 12×16 deck**

If your deck is 12×16 foot with posts which spaced 6 feet apart in shorter side (12-foot side) and 5 or 6 feet apart in longer side (16-foot side) on center will require 10 posts, plus atleast 2 posts more if you are planning on building stairs. The attached 12’×16′ deck will need 4 posts plus atleast 2 more for stairs.

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**How many posts do i need for a 10×20 deck**

If your deck is 10×20 foot with posts which spaced 5 feet apart in shorter side (10-foot side) and 5 feet apart in longer side (20-foot side) on center will require 12 posts, plus atleast 2 posts more if you are planning on building stairs. The attached 10’×20′ deck will need 5 posts plus atleast 4 more for two stairs.

**How many posts do i need for a 10×12 deck**

If your deck is 10×12 foot with posts which spaced 5 feet apart in shorter side (10-foot side) and 6 feet apart in longer side (12-foot side) on center will require 8 posts, plus atleast 2 posts more if you are planning on building stairs. The attached 10’×12′ deck will need 3 posts plus atleast 2 more for stairs.

**How many posts do i need for a 12×12 deck**

If your deck is 12×12 foot with posts which spaced 6 feet apart each side on center will require 8 posts, plus atleast 2 posts more if you are planning on building stairs. The attached 12’×12′ deck will need 3 posts plus atleast 2 more for stairs.

**How many posts do i need for a 16×16 deck**

If your deck is 16×16 foot with posts which spaced 4 feet apart each side on center will require 12 posts, plus atleast 2 posts more if you are planning on building stairs. The attached 16’×16′ deck will need 5 posts plus atleast 2 more for stairs.

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**Conclusions:**

If your deck is 10×10 foot with posts which spaced 5 feet apart each side on center will require 8 posts, plus atleast 2 posts more if you are planning on building stairs.