Roof - Rafters cost

The Total Cost of Rafter Boards calculator computes the cost of lumber based on the unit price and the number of rafters required for a gabled roof (see diagram).

INSTRUCTIONS: Choose units and enter the following:

• (L)  Ridge Length
• (S) Roof Span
• (P) Roof Pitch
• (oC) on-Center spacing
• (uP) Unit Price of the boards (see below)

Total Cost (TC):  The calculator computes the number of rafters in the roof and applies the unit price to compute the total cost in U.S. dollars.  However, this can be automatically converted into other currency units via the pull-down menu.

This function assumes that the pitch of the roof is the same on both sides.  For roofs of different pitches, one must estimate the cost of the rafters one each side individually, since they will be different.  It also assumes that a single rafter board will go from the edge of the roof to the roof's ridge (i.e. no scabbing boards together).  Also note, the width of the boards, whether 2x6 or larger must be chosen based on the load requirement and local building codes.

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

The most recent 2x6 price survey information is:

• Date of Survey: 4/10/24
• Store (online) Surveyed: Menards 
  • 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

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

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

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