Shelf Sag Tables – 12″ Deep Shelves


These tables contain comparative shelf sag measurements for 12″ deep shelves ranging in width from 30″ to 54″.  Six types of shelving materials (all 3/4″ thick), three shelf loads (20, 30, 40 pounds per linear foot), and several shelf support techniques are represented. Sag measurements are to the nearest hundredth of an inch. As a general guideline, shelf sag should be 0.10″ or less.

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Shelf Width: 30″           (Optimal sag: 0.05″ or less,  excessive: 0.13″+ )

End Support Front Support Rear Support Lbs per ft Lbs total MDF Plywood Pine Poplar Cherry Oak
Float No No 20 50 .04 .03 .02 .02 .02 .02
Float No No 30 75 .08 .05 .03 .03 .03 .03
Float No No 40 100 .11 .07 .05 .04 .05 .05
Fixed No No 20 50 .04 .03 .03 .02 .03 .02
Fixed No No 30 75 .06 .04 .04 .03 .05 .02
Fixed No No 40 100 .07 .05 .05 .04 .07 .04
Fixed Yes No 20 50 .02 .01 .01 .01 .01 .01
Fixed Yes No 30 75 .03 .01 .01 .01 .02 .01
Fixed Yes No 40 100 .04 .02 .02 .02 .02 .02
Fixed No Yes 20 50 .03 .03 .03 .02 .02 .02
Fixed No Yes 30 75 .04 .04 .03 .03 .03 .03
Fixed No Yes 40 100 .05 .05 .05 .04 .04 .04
Fixed Yes Yes 20 50 .01 .01 .01 .01 .01 .01
Fixed Yes Yes 30 75 .01 .01 .01 .01 .01 .01
Fixed Yes Yes 40 100 .02 .02 .02 .02 .01 .02

 

Shelf Width: 36″           (Optimal sag: 0.06″ or less,  excessive: 0.18″+)

End Support Front Support Rear Support Lbs per ft Lbs total MDF Plywood Pine Poplar Cherry Oak
Float No No 20 60 .14 .07 .04 .05 .06 .05
Float No No 30 90 .22 .10 .06 .06 .08 .06
Float No No 40 120 .32 .14 .10 .09 .11 .08
Fixed No No 20 60 .08 .04 .05 .04 .04 .03
Fixed No No 30 90 .12 .06 .06 .05 .05 .04
Fixed No No 40 120 .18 .09 .09 .07 .08 .07
Fixed Yes No 20 60 .04 .02 .02 .02 .02 .02
Fixed Yes No 30 90 .06 .03 .02 .02 .03 .02
Fixed Yes No 40 120 .09 .05 .04 .03 .04 .03
Fixed No Yes 20 60 .05 .04 .04 .02 .03 .03
Fixed No Yes 30 90 .06 .05 .05 .04 .04 .04
Fixed No Yes 40 120 .08 .07 .07 .05 .05 .05
Fixed Yes Yes 20 60 .02 .01 .01 .01 .02 .01
Fixed Yes Yes 30 90 .03 .02 .02 .02 .02 .02
Fixed Yes Yes 40 120 .05 .03 .03 .03 .03 .03

 

Shelf Width: 42″            (Optimal sag: 0.07″ or less,  excessive 0.21″+)

End Support Front Support Rear Support Lbs per ft Lbs total MDF Plywood Pine Poplar Cherry Oak
Float No No 20 70 .28 .13 .08 .07 .08 .07
Float No No 30 105 .43 .18 .15 .13 .12 .10
Float No No 40 140 .58 .24 .21 .17 .17 .13
Fixed No No 20 70 .15 .10 .09 .06 .08 .05
Fixed No No 30 105 .22 .15 .14 .10 .10 .09
Fixed No No 40 140 .30 .20 .18 .13 .13 .12
Fixed Yes No 20 70 .07 .05 .04 .03 .04 .04
Fixed Yes No 30 105 .11 .06 .07 .05 .05 .05
Fixed Yes No 40 140 .16 .10 .10 .08 .07 .06
Fixed No Yes 20 70 .08 .07 .07 .05 .05 .05
Fixed No Yes 30 105 .11 .11 .09 .08 .07 .07
Fixed No Yes 40 140 .13 .13 .12 .10 .09 .09
Fixed Yes Yes 20 70 .04 .03 .03 .03 .02 .02
Fixed Yes Yes 30 105 .05 .04 .04 .04 .03 .03
Fixed Yes Yes 40 140 .07 .05 .05 .05 .05 .04

 

Shelf Width: 48″           (Optimal sag: 0.08″ or less,  excessive: 0.24″+)

End Support Front Support Rear Support Lbs per ft Lbs total MDF Plywood Pine Poplar Cherry Oak
Float No No 20 80 .48 .16 .14 .14 .14 .12
Float No No 30 120 .76 .30 .23 .24 .21 .17
Float No No 40 160 1.04 .39 .34 .30 .29 .23
Fixed No No 20 80 .23 .12 .12 .11 .10 .08
Fixed No No 30 120 .36 .19 .19 .17 .16 .14
Fixed No No 40 160 .49 .26 .25 .22 .21 .18
Fixed Yes No 20 80 .14 .06 .07 .04 .04 .03
Fixed Yes No 30 120 .22 .11 .11 .08 .08 .06
Fixed Yes No 40 160 .30 .16 .15 .12 .11 .08
Fixed No Yes 20 80 .10 .10 .09 .08 .08 .06
Fixed No Yes 30 120 .13 .16 .13 .11 .10 .09
Fixed No Yes 40 160 .16 .20 .17 .14 .13 .12
Fixed Yes Yes 20 80 .06 .04 .04 .03 .03 .03
Fixed Yes Yes 30 120 .08 .07 .06 .05 .07 .05
Fixed Yes Yes 40 160 .10 .09 .08 .07 .08 .07

 

Shelf Width: 54″           (Optimal sag: 0.09″ or less,  excessive: 0.27″+)

End Support Front Support Rear Support Lbs per ft Lbs total MDF Plywood Pine Poplar Cherry Oak
Float No No 20 90 .70 .27 .27 .20 .22 .16
Float No No 30 135 1.23 .50 .44 .34 .34 .25
Float No No 40 180 1.8 .69 .60 .46 .47 .34
Fixed No No 20 90 .31 .20 .18 .14 .14 .12
Fixed No No 30 135 .55 .35 .29 .23 .22 .18
Fixed No No 40 180 .84 .44 .41 .33 .32 .26
Fixed Yes No 20 90 .13 .09 .09 .08 .05 .05
Fixed Yes No 30 135 .25 .19 .14 .14 .11 .10
Fixed Yes No 40 180 .40 .28 .21 .20 .19 .15
Fixed No Yes 20 90 .09 .15 .13 .10 .08 .08
Fixed No Yes 30 135 .14 .22 .18 .15 .14 .11
Fixed No Yes 40 180 .18 .28 .23 .18 .19 .15
Fixed Yes Yes 20 90 .05 .06 .08 .06 .03 .04
Fixed Yes Yes 30 135 .08 .12 .19 .09 .07 .08
Fixed Yes Yes 40 180 .11 .18 .15 .12 .10 .10