Floor Joist Span Calculator | EZ Virtual Tools Construction

Floor Joist Requirements

Required Span (ft)

Joist Spacing

Joist Size

Lumber Species

Lumber Grade

Live Load (PSF)

Dead Load (PSF)

Deflection Limit

Span Analysis

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Status
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0' 0"
Max Allowable
span
0 m

0' 0"

Required

span

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Joist Size

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0.00"

Deflection

@ span

0.00"

Allowable Defl

L/360

IRC Floor Joist Span Table (40 PSF Live / 10 PSF Dead, L/360)

Size	Grade	12" O.C.	16" O.C.	24" O.C.
2x6	No. 2 SPF	9'-8"	8'-6"	7'-0"
2x8	No. 2 SPF	12'-9"	11'-3"	9'-3"
2x10	No. 2 SPF	16'-3"	14'-4"	11'-9"
2x12	No. 2 SPF	19'-9"	17'-5"	14'-4"
2x8	No. 2 DF-L	13'-10"	12'-3"	10'-1"
2x10	No. 2 DF-L	17'-8"	15'-7"	12'-10"
2x12	No. 2 DF-L	21'-6"	18'-11"	15'-7"

IRC R502.3.1: Floor joist spans shown are based on No. 2 grade lumber with 10 PSF dead load. For higher dead loads or special conditions, reduce spans or consult an engineer.