The Cost of Floor Joists calculator computes the cost of lumber based on the unit price and the number of joists required for a floor based on the dimension of the room.
INSTRUCTIONS: Choose your preferred units and enter the following:
- (W) Width of Floor across joists
- (L) Length of Floor parallel to the joists
- (oC) On-center separation between joists (default to 16 inches)
- (uP) Unit Price of a floor Joist board
TOTAL PRICE: The calculator computes the number of floor joist boards needed and applies the unit price to compute a total cost in U.S. dollars. However, this can be automatically converted into other currency units (e.g. Pesos) via the pull-down menu.
The Math / Science
ASSUMPTIONS: this algorithm assumes that the following:
- the length of the area is less than or equal to the length of one joist. For spans greater than the length of one joist, a beam is often required and a second row of joists. This would double the number and cost of joists.
- the plate boards are approximately the same size as the joists.
Unit Price (Lumber Prices)
One should always use local pricing for the unit price of a supply like lumber for rafter lumber. However, for convenience, the following prices of 2x6s, 2x8s, 2x10s and 2x12s were observed on the Internet and presented for your convenience
2x6 Price Survey
The 2x6 Lumber Pricing table contains recent lumber prices for 2x6 of a variety of lengths with prices from Lowes, Home Depot, Menards and potentially other stores based on their web sites.
This table is a repository of pricing data for common lumber (2x6's) as surveyed from the websites of major lumber retailers in the United States.
2x6 price survey:
- 2x6 Price Survey Date: 4/10/24
- 2x6 Price Survey Store: Menards
- 2x6 Price by Length
- Price of an 8' 2x6: $6.98
- Price of a 10' 2x6: $10.53
- Price of a 12' 2x6: $11.52
- Price of a 16' 2x6: $14.62
All prices are in U.S. dollars and based on searches of nationally advertised prices from the provider's web sites. Search string: "kiln dried 2x6 lumber" is used in the retailer's website. The term two by six (2x6) refers to the rough cut dimensions of construction grade lumber. However, the typical 2x6 purchased at a lumber yard is actually `1 3/4`" x `5 1/2`". Nonetheless, the term 2x6 persists. These values can be used in the Stud Framing Calculator and the Joist Framing Calculator.
NOTE: Local pricing should ALWAYS, ALWAYS, ALWAYS be used! These price points are for estimation convenience only, and there is no guarantee on the prices of the product nor of their availability at the stated price.
2x8 Price Survey
The 2x8 Lumber Pricing table contains recent lumber prices for 2x8 of a variety of lengths with prices from Lowes, Home Depot, Menards and potentially other stores based on their web sites.
This table is a repository of pricing data for common lumber (2x8's) as surveyed from the websites of major lumber retailers in the United States.
The most recent 2x8 lumber price survey information is:
- Date of Survey: 4/11/24
- Store (online) Surveyed: Menards
- Price of an 8' 2x8: $11.99
- Price of a 10' 2x8: $13.99
- Price of a 12' 2x8: $15.77
- Price of a 16' 2x8: $20.76
All prices are in U.S. dollars and based on searches of nationally advertised prices from the provider's web sites. Search string: "kiln dried 2x8 lumber" is used in the retailer's website. The term two by eight (2x8) refers to the rough cut dimensions of construction grade lumber. However, the typical 2x8 purchased at a lumber yard is actually `1 3/4`" x `7 1/2`". Nonetheless, the term 2x8 persists. These values can be used in the Joist Framing Calculator.
NOTE: Local pricing should ALWAYS, ALWAYS, ALWAYS be used! These price points are for estimation convenience only, and there is no guarantee on the prices of the product nor of their availability at the stated price.
2x10 Price Survey
The 2x10 Lumber Pricing table contains recent lumber prices for 2x10 of a variety of lengths with prices from Lowes, Home Depot, Menards and potentially other stores based on their web sites.
This table is a repository of pricing data for common lumber (2x10's) as surveyed from the websites of major lumber retailers in the United States.
The most recent 2x10 lumber price survey information is:
- Date of 2x10 Lumber Price Survey: 4/11/24
- Store (online) Surveyed: Menards
- Price of an 8' 2x10: $14.99
- Price of a 10' 2x10: $19.99
- Price of a 12' 2x10: $23.99
- Price of a 14' 2x10: $24.99
- Price of a 16' 2x10: $28.28
All prices are in U.S. dollars and based on searches of nationally advertised prices from the provider's web sites. Search string: "kiln dried 2x10 lumber" is used in the retailer's website. The term two by ten (2x10) refers to the rough cut dimensions of construction grade lumber. However, the typical 2x10 purchased at a lumber yard is actually `1 3/4`" x `9 1/2`". Nonetheless, the term 2x10 persists. These values can be used in the Joist Framing Calculator.
NOTE: Local pricing should ALWAYS, ALWAYS, ALWAYS be used! These price points are for estimation convenience only, and there is no guarantee on the prices of the product nor of their availability at the stated price.
2x12 Price Survey
The 2x12 Lumber Pricing table contains recent lumber prices for 2x12 of a variety of lengths with prices from Lowes, Home Depot, Menards and potentially other stores based on their web sites.
This table is a repository of pricing data for common lumber (2x12's) as surveyed from the websites of major lumber retailers in the United States.
The most recent 2x12 lumber price survey information is:
- Date of 2x12 Lumber Price Survey: 4/11/24
- Store (online) Surveyed: Menards
- Price of a 12' 2x12: $34.99
- Price of a 14' 2x12: $36.99
- Price of a 16' 2x12: $42.99
- Price of an 18' 2x12: $69.99
- Price of a 20' 2x12: $65.99
All prices are in U.S. dollars and based on searches of nationally advertised prices from the provider's web sites. Search string: "kiln dried 2x12 lumber" is used in the retailer's website. The term two by twelve (2x12) refers to the rough cut dimensions of construction grade lumber. However, the typical 2x12 purchased at a lumber yard is actually `1 3/4`" x `11 1/2`". Nonetheless, the term 2x12 persists. These values can be used in the Joist Framing Calculator.
NOTE: Local pricing should ALWAYS, ALWAYS, ALWAYS be used! These price points are for estimation convenience only, and there is no guarantee on the prices of the product nor of their availability at the stated price.
Deck Builder Calculator provides estimates for a simple rectangular deck project. Calculator functions include the following:
- Deck Board Count: Computes the number of decking boards needed for your deck based on the size of the deck and the size of the decking boards.
- Deck Boards Cost: Computes the cost of deck board flooring based on a computed number of deck boards and the price per board.
- Decking Cost Estimate: Estimates the cost of wood board decking based on total area and unit pricing in dollars per square feet.
- Subfloor 4x8 Sheets: Computes the number of 4x8 sheets to cover floor/deck area.
- Subfloor Cost: Computes the cost of 4x8 sheets to cover fool/deck area.
- Deck Joist Count: Computes the number of floor joists needed for a deck. It returns the number of joists and plate boards, square feet of area and the length of the diagonal.
- Joists on Beams
: Computes the number of joists (2x dimensional lumber or i-joists), number of beams, number of joist hangers, and length of plate boards needed for a floor or deck with a span that might require one or more beams. - Deck Joist Cost: Computes the total cost of the floor joist boards.
- Deck Stain and Sealer: Computes the amount of stain and sealer needed for a deck.
Joist Calculators
- Floor Joist Count:
Computes the number of joists (joists and end plates) and joist ties required for a floor or deck based on the dimension of the room or deck and the on-center joist separation. - Floor Joist Cost: Estimates the cost of Floor Joist boards (joists and end plates) required for a floor or deck based on the dimensions of the deck, spacing of joists and unit cost of joist boards.
- Joist Hanger Count:
Computes the number of joist hangers required for a deck based on the width of the deck and the spacing of joists. - I-Joist Count: Computes the the number of I-Joist boards required to cover a span (width) based on the size of the span and spacing of the I-Joists.
- Maximum Joist Span: Computes the span length of a (1,200 pounds per square inch fiber stress) wood joist based on the live load, spacing, board width (e.g., 2x6 vs 2x10) and whether the joist need to be extra stiff for materials attached such as plaster below them.
- Joists on Beams:
Computes the number of joists (2x dimensional lumber or i-joists), number of beams, number of joist hangers, and length of plate boards needed for a floor or deck with a span that might require one or more beams. - On Center Spacing: Computes the even spacing between a number of objects (e.g. posts, studs, joists, rafters, trusses, lights, rebars) over a specified length or distance.
Building Calculators
- Area of a Roof
- Pitch of a Roof
- Number of Trusses Needed for a Roof
- 4x8s needed for a roof
- Shingles needed for a roof
- Number and Length of Metal Roof Panels
- Number and Length of Purlins
- Number and Length of Rafters
- Number and Length of Rafter and Collar ties
- Number and Length of wall top and bottom wall plates
- Number of Studs for a Room
- Number of Studs in a Wall
- Room Interior Area (wall and ceiling)
- Cubic Feet in a Room (volume)
- Number of 4x8 or 4x12 Sheets for a Room
