Beam Load Calculator Formula
Understand the math behind the beam load calculator. Each variable explained with a worked example.
Formulas Used
Total Load
total_load_psf = total_psfLoad per Linear Foot
load_per_ft = load_per_linftTotal Beam Load
total_beam_load = load_per_linft * spanReaction per Support (uniform)
reaction_per_support = load_per_linft * span / 2Variables
| Variable | Description | Default |
|---|---|---|
span | Beam Span(feet) | 16 |
tributary_width | Tributary Width(feet) | 8 |
dead_load | Dead Load (floor/roof weight)(psf) | 15 |
live_load | Live Load(psf) | 40 |
total_psf | Derived value= dead_load + live_load | calculated |
load_per_linft | Derived value= total_psf * tributary_width | calculated |
How It Works
How to Calculate Beam Loading
Formula
Load per Linear Foot = (Dead Load + Live Load) × Tributary Width
Total Load = Load per Linear Foot × Span
Support Reaction = Total Load / 2 (for a uniformly loaded simple beam)
Tributary width is the distance from the beam centerline to the midpoint between the beam and the next parallel support on each side. This calculation assumes a uniformly distributed load on a simply supported beam.
Worked Example
A 16 ft beam with 8 ft tributary width, 15 psf dead load, 40 psf live load.
span = 16tributary_width = 8dead_load = 15live_load = 40
- 01Total load = 15 + 40 = 55 psf
- 02Load per linear foot = 55 × 8 = 440 lbs/ft
- 03Total beam load = 440 × 16 = 7,040 lbs
- 04Reaction per support = 7,040 / 2 = 3,520 lbs
Ready to run the numbers?
Open Beam Load Calculator