Deck Joist Span Calculator

Inputs

View results
Common North American dressed lumber sizes. Use custom for measured actual width and depth.
On-center joist spacing. Area loads are multiplied by this tributary width to get line load.
in
Uniform live load on the tributary deck area. Default is an example, not a code table.
psf
Uniform dead load on the tributary deck area, including decking, framing allowance and finishes.
psf
Use the adjusted modulus required by your design basis. Default is an example only.
Mpsi
Adjusted allowable bending design value for the selected species, grade, size and deck conditions.
ksi
Adjusted allowable shear design value. Default is an example only.
ksi
For L/360, enter 360. Applied to live-load deflection only.
For L/240, enter 240. Applied to live plus dead load deflection.
Optional joist clear span to check against the same bending, shear and deflection criteria.
ft

Results

Default result
Edit inputs
Max joist span(L_allow)
14.63ft
Pass

Governing deck joist span check: bending stress.

Minimum of bending, shear, live-deflection and total-deflection spans.

Also computed

Checked-span utilization(U_max)Pass0.6732

Utilization at the entered check span (2x10 actual 1.5 x 9.25 in).

Bending-controlled span(L_b)14.63ft

Shear-controlled span(L_v)37.46ft

Live-deflection span(L_delta,L)14.88ft

Total-deflection span(L_delta,T)15.82ft

Total line load per joist(w)66.67lb/ft

Surface live + dead load multiplied by joist spacing.

Method notes 4 notes
  • Uses 2x10 actual 1.5 x 9.25 in; line load is area load multiplied by joist spacing.
  • Simple-span uniform-load screen only: M = w*L^2/8, V = w*L/2, delta = 5*w*L^4/(384*E*I).
  • Enter adjusted E, Fb and Fv values from the same code/design edition and species/grade/treatment/service-condition basis. Defaults are examples, not a span table.
  • Does not check cantilevers, multi-span continuity, beams/girders, bearing, notches, holes, lateral restraint, vibration, ledgers, hangers, fasteners, guard loads, hot tubs, concentrated loads, snow drift, footing design or permit acceptance.

Powered by MachineCalcs ↗