Loads and reactions act on the beam.
Structural engineering unit converter
Bending Moment Unit Converter
Convert bending moment units used in beam analysis, applied moments, bending moment diagrams, hand checks, and metric-to-imperial calculations.
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Convert moment units
Next step
Use as an applied moment
Send the converted value to the Beam Calculator and add its location along the span.
Visual beam mechanics
How bending moment works
A bending moment measures the turning effect of a force and the internal flexural demand it creates in a beam. Follow the four schematics from cause to beam response.
Mmoment
=
Fforce
×
d⊥perpendicular distance
1
A force creates a turning effect
The farther the force acts from the reference point, the larger the moment.
2
An applied moment acts at one location
A concentrated couple produces rotation without a net vertical force at that point.
3
Beam loads create internal moment
Every cut through the beam must balance the loads acting on one side of that cut.
4
Moment bends the beam
Sagging and hogging reverse which face is in tension and compression.
The value changes along the span.
Section stiffness and geometry resist bending.
Quick reference
Common bending moment conversions
These relationships cover the moment units most often shown on beam diagrams and calculation sheets.
| From | Equivalent |
|---|---|
| 1 kN·m | 737.562 lb·ft |
| 1 kN·m | 0.737562 kip·ft |
| 1 kN·m | 8,850.746 lb·in |
| 1 kip·ft | 1.355818 kN·m |
| 1 lb·ft | 12 lb·in |
| 1 N·m | 1,000 N·mm |
Engineering context
Moment units in beam analysis
Bending moment is force multiplied by perpendicular distance. That produces units such as kN·m, N·mm, kip·ft, and lb·in.
A beam diagram reports the internal bending moment along the span. Keep one consistent force and length system throughout a calculation before comparing demand with section resistance.
Bending moment vs. torque
They share the same force × distance units, but describe different actions. Torque twists a member about its longitudinal axis; bending moment produces flexure.
Where this conversion is used
Structural engineering applications
- Applied couple loads in a beam model
- Bending moment diagram ordinates
- Metric and imperial hand-check reconciliation
- Moment demand used in bending stress checks
Questions engineers ask
Moment conversion FAQ
What are moment units?
Moment units are force multiplied by distance, such as kN·m, N·mm, kip·ft, lb·ft, or lb·in.
Is kN-m the same as kN·m or kNm?
Yes. kN-m, kN·m, and kNm are common text formats for kilonewton-metre. The centred dot makes the multiplication clearer.
How do I convert kN·m to lb·ft?
Multiply kN·m by approximately 737.562. For example, 10 kN·m is approximately 7,375.62 lb·ft.
What is the difference between lb·ft and lb·in?
They use different distance units. One lb·ft equals 12 lb·in.
How does a point load create bending moment in a beam?
At any cut through the beam, the internal bending moment balances the moments of the external loads and reactions on one side of the cut. That value changes with position along the span.
What do sagging and hogging mean?
Sagging bends a beam into a smile-like curve and typically puts the bottom fibres in tension. Hogging bends it the opposite way and typically puts the top fibres in tension.
What moment unit should I use in the Beam Calculator?
Use the force and length units selected in the calculator. The handoff on this page converts the value to the calculator’s current metric or imperial input format.
Conversion factors follow SI and U.S. customary unit relationships. Rounded reference values are for convenience; the live converter uses higher-precision factors.