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Calculate maximum floor joist spans based on wood species, grade, size, spacing, and load conditions. Compare spans across different lumber grades and species to find the most cost-effective solution for your construction project.
Load Condition Presets
Maximum Span
19 ft
at 16" OC spacing
Max Deflection
0.63"
at live load
Stress Ratio
71.4%
utilization
Rating
Optimal
capacity utilization
Same span (19 ft) with different sizes and grades:
| Size | Grade | Max Span | Cost Factor |
|---|---|---|---|
| 2x6 | #1 | 9.11 ft | Baseline |
| 2x8 | #1 | 13.2 ft | Baseline |
| 2x10 | #1 | 16.11 ft | Baseline |
| 2x12 | #1 | 20.8 ft | Baseline |
| 2x14 | #1 | 24 ft | Baseline |
Maximum residential floor joist spans (40 psf live load, 10 psf dead load, L/360 deflection) at various spacings.
| Size | 12" OC | 16" OC | 24" OC |
|---|---|---|---|
| 2x6 | 12.10 | 10.9 | 8.9 |
| 2x8 | 16.6 | 14.8 | 12.1 |
| 2x10 | 21.2 | 19 | 15.6 |
| 2x12 | 25.10 | 23.2 | 19 |
| 2x14 | 30 | 27.2 | 22.3 |
| Size | 12" OC | 16" OC | 24" OC |
|---|---|---|---|
| 2x6 | 11.2 | 9.11 | 8.1 |
| 2x8 | 14.10 | 13.2 | 10.10 |
| 2x10 | 19 | 16.11 | 13.10 |
| 2x12 | 23.2 | 20.8 | 17.1 |
| 2x14 | 27 | 24 | 19.8 |
| Size | 12" OC | 16" OC | 24" OC |
|---|---|---|---|
| 2x6 | 10.2 | 8.10 | 7.2 |
| 2x8 | 13.6 | 11.10 | 9.8 |
| 2x10 | 17.4 | 15.6 | 12.8 |
| 2x12 | 21.2 | 18.11 | 15.6 |
| 2x14 | 24.8 | 22.1 | 18.1 |
| Size | 12" OC | 16" OC | 24" OC |
|---|---|---|---|
| 2x6 | 7.6 | 6.5 | 5.2 |
| 2x8 | 9.10 | 8.4 | 6.9 |
| 2x10 | 12.6 | 10.8 | 8.9 |
| 2x12 | 15.2 | 13 | 10.8 |
| 2x14 | 17.8 | 15.2 | 12.6 |
| Size | 12" OC | 16" OC | 24" OC |
|---|---|---|---|
| 2x6 | 11.8 | 10.6 | 8.8 |
| 2x8 | 15.8 | 14.2 | 11.8 |
| 2x10 | 20.2 | 18.2 | 15 |
| 2x12 | 24.6 | 22.2 | 18.2 |
| 2x14 | 28.8 | 26 | 21.4 |
| Size | 12" OC | 16" OC | 24" OC |
|---|---|---|---|
| 2x6 | 10.8 | 9.4 | 7.8 |
| 2x8 | 14.4 | 12.10 | 10.6 |
| 2x10 | 18.4 | 16.4 | 13.4 |
| 2x12 | 22.6 | 20.2 | 16.6 |
| 2x14 | 26.2 | 23.6 | 19.4 |
| Size | 12" OC | 16" OC | 24" OC |
|---|---|---|---|
| 2x6 | 9.6 | 8.4 | 6.10 |
| 2x8 | 12.10 | 11.4 | 9.4 |
| 2x10 | 16.4 | 14.8 | 12.2 |
| 2x12 | 20.2 | 18.2 | 15 |
| 2x14 | 23.6 | 21.2 | 17.4 |
| Size | 12" OC | 16" OC | 24" OC |
|---|---|---|---|
| 2x6 | 7.2 | 6.2 | 5 |
| 2x8 | 9.4 | 8.1 | 6.6 |
| 2x10 | 12 | 10.2 | 8.4 |
| 2x12 | 14.6 | 12.6 | 10.4 |
| 2x14 | 17 | 14.6 | 12 |
| Size | 12" OC | 16" OC | 24" OC |
|---|---|---|---|
| 2x6 | 12.6 | 11.2 | 9.2 |
| 2x8 | 16.8 | 15.1 | 12.4 |
| 2x10 | 21.6 | 19.4 | 15.10 |
| 2x12 | 26.4 | 23.10 | 19.6 |
| 2x14 | 30.10 | 27.10 | 22.10 |
| Size | 12" OC | 16" OC | 24" OC |
|---|---|---|---|
| 2x6 | 11.4 | 10.2 | 8.4 |
| 2x8 | 15.2 | 13.8 | 11.4 |
| 2x10 | 19.6 | 17.8 | 14.6 |
| 2x12 | 24 | 21.10 | 18 |
| 2x14 | 28 | 25.4 | 20.10 |
| Size | 12" OC | 16" OC | 24" OC |
|---|---|---|---|
| 2x6 | 10.2 | 9.1 | 7.5 |
| 2x8 | 13.8 | 12.4 | 10.2 |
| 2x10 | 17.8 | 16 | 13.1 |
| 2x12 | 21.8 | 19.6 | 16.1 |
| 2x14 | 25.4 | 23 | 18.9 |
| Size | 12" OC | 16" OC | 24" OC |
|---|---|---|---|
| 2x6 | 7.6 | 6.6 | 5.4 |
| 2x8 | 10.2 | 8.9 | 7.2 |
| 2x10 | 13 | 11.2 | 9.2 |
| 2x12 | 15.10 | 13.8 | 11.3 |
| 2x14 | 18.5 | 16 | 13.1 |
| Size | 12" OC | 16" OC | 24" OC |
|---|---|---|---|
| 2x6 | 11.4 | 10.2 | 8.4 |
| 2x8 | 15.2 | 13.8 | 11.4 |
| 2x10 | 19.6 | 17.8 | 14.6 |
| 2x12 | 24 | 21.10 | 18 |
| 2x14 | 28 | 25.4 | 20.10 |
| Size | 12" OC | 16" OC | 24" OC |
|---|---|---|---|
| 2x6 | 10.4 | 9.2 | 7.6 |
| 2x8 | 13.10 | 12.4 | 10.2 |
| 2x10 | 17.8 | 15.10 | 13 |
| 2x12 | 21.8 | 19.6 | 16.1 |
| 2x14 | 25.4 | 23 | 18.9 |
| Size | 12" OC | 16" OC | 24" OC |
|---|---|---|---|
| 2x6 | 9.4 | 8.2 | 6.8 |
| 2x8 | 12.6 | 11.2 | 9.2 |
| 2x10 | 16 | 14.4 | 11.10 |
| 2x12 | 19.8 | 17.8 | 14.6 |
| 2x14 | 23 | 20.8 | 17 |
| Size | 12" OC | 16" OC | 24" OC |
|---|---|---|---|
| 2x6 | 7 | 6 | 4.11 |
| 2x8 | 9.2 | 7.11 | 6.6 |
| 2x10 | 11.8 | 10.2 | 8.4 |
| 2x12 | 14.4 | 12.4 | 10.2 |
| 2x14 | 16.8 | 14.5 | 11.11 |