Calculate Weight on a Pole

Determine load distribution and support reactions for static loads

Whether you are an engineering student, a construction foreman, or simply moving heavy furniture with a friend, knowing how to calculate weight on a pole is a fundamental physics skill. This calculation determines how much force is exerted on each end of a beam or pole when a load is placed at a specific point.

What is "Calculate Weight on a Pole"?

To calculate weight on a pole means to determine the reaction forces at the support points (often called fulcrums or pivot points) of a horizontal beam. This is a classic problem in statics, a branch of mechanics dealing with bodies in equilibrium.

In a real-world scenario, if two people are carrying a heavy box suspended on a pole, they rarely carry the exact same weight unless the box is perfectly centered. The person closer to the box carries a significantly higher percentage of the load. This calculator helps you quantify exactly how much extra weight that is.

Calculate Weight on a Pole: Formula and Explanation

The math behind this calculation relies on two conditions of static equilibrium:

1. Sum of Vertical Forces = 0: The upward forces (supports) must equal the downward forces (load + pole weight).
2. Sum of Moments (Torque) = 0: The rotational force around any point must be zero.

The standard formula to find the force on the Right Support ($R_b$) is:

$$R_b = \frac{(W_{load} \times d_{load}) + (W_{pole} \times \frac{L}{2})}{L}$$

Variable Definitions

Variable	Meaning	Unit	Typical Range
L	Total Length of Pole	m / ft	2m – 10m
Wload	Weight of the Load	kg / lbs	10kg – 1000kg
dload	Distance from Left Support	m / ft	0 to L
Wpole	Weight of Pole (Self-weight)	kg / lbs	5kg – 50kg

Practical Examples (Real-World Use Cases)

Example 1: The Movers

Two movers are carrying a 100kg sofa using a 4-meter lifting strap (acting as the pole). The sofa slips and settles 1 meter from the person on the left (Person A).

• Pole Length (L): 4m
• Load (W): 100kg
• Position (x): 1m
• Pole Weight: Negligible (0kg)

Result: Person A carries 75kg, while Person B carries only 25kg. Because the load is 3 times closer to Person A, they carry 3 times the share of Person B.

Example 2: Structural Beam

A 10-meter steel beam weighs 500kg (uniform). A machine weighing 2000kg is placed 8 meters from the left wall.

• Self-Weight Effect: The 500kg beam weight is split 250kg/250kg because it is uniform.
• Load Effect: The 2000kg load is 8m from the left, meaning it is 2m from the right. The right support takes 80% of this load (1600kg).
• Total Calculation: Left Support = 250kg + 400kg = 650kg. Right Support = 250kg + 1600kg = 1850kg.

How to Use This Calculator

Our tool simplifies the math so you can plan safe lifts or structural designs instantly.

1. Enter Dimensions: Input the total length of the pole or beam.
2. Define the Load: Enter the weight of the object being supported.
3. Set Position: Specify how far the load is from the left-hand side (Support A).
4. Include Self-Weight: If the pole itself is heavy (like a steel I-beam), enter its weight for higher accuracy.
5. Analyze Results: Use the "Copy Results" button to save the force distribution data for your reports.

Key Factors That Affect Results

When you calculate weight on a pole, several external factors can influence the final safety and stability of the system.

• Load Position (Lever Arm): This is the most critical factor. Moving a load just a few inches toward one end can drastically increase the force on that support, potentially causing failure or injury.
• Pole Flexibility: This calculator assumes a rigid pole. If the pole bends significantly, the geometry changes, and horizontal forces may be introduced.
• Material Density: A denser pole adds more self-weight. In long-span bridges or beams, the weight of the structure often exceeds the weight of the traffic it carries.
• Dynamic Loading: If the load is bouncing or moving (like a person walking on a plank), the peak forces can be 2-3 times higher than the static weight calculated here.
• Support Integrity: Knowing the weight is only half the battle; the support (or person) must be strong enough to handle that specific concentrated force.
• Angle of Inclination: If the pole is not horizontal, gravity acts at an angle, reducing the vertical load but adding horizontal thrust (sliding force).

Frequently Asked Questions (FAQ)

Does the weight of the pole matter?

For light loads or short poles (like a broomstick), it is negligible. For structural engineering or heavy lifting (like steel beams), the self-weight is critical and must be included in the calculation.

What happens if the load is exactly in the middle?

If the load is at L/2 (center), both supports share the weight equally (50/50), assuming the pole is uniform.

Can I use this for vertical columns?

No. This tool calculates transverse loads on a horizontal beam. Vertical columns require "buckling load" calculations using Euler's formula.

Why is the unit generic?

Physics ratios work the same regardless of unit. You can use Kilograms, Pounds, or Newtons, as long as you are consistent across all inputs.

What if there are multiple loads?

You can calculate the reaction for each load individually and sum them up (Principle of Superposition).

Does the height of the supports matter?

For simple static vertical loading, no. However, if supports are uneven, the load might slide, introducing horizontal forces.

How does this relate to torque?

The calculation is entirely based on torque (moment). We balance the clockwise torque against the counter-clockwise torque around a pivot point.

Is this safe for rigging calculations?

While accurate for statics, professional rigging requires safety factors (usually 5:1) and consideration of dynamic forces. Always consult a professional engineer for critical lifts.