Even split. One leg may be taking far more than this.
Do the legs measure the same?
Will the load hang level?
About this tool
Two legs at 30° do not each carry half the load. They each carry all of it. This works out what is really in your slings before you pick.
Pick a chain for this tension ›
The angle factor table
This is the whole idea in one table. Multiply each leg’s straight-down share by the factor for your angle and you have the tension in the leg.
| Angle from horizontal | Factor | What that means |
|---|---|---|
| 90° | ×1.000 | Straight up. Each leg takes its plain share. |
| 75° | ×1.035 | Barely more than straight up. |
| 70° | ×1.064 | About 6% more in each leg. |
| 60° | ×1.155 | The everyday angle. 15% more. |
| 55° | ×1.221 | 22% more. |
| 50° | ×1.305 | Nearly a third more. |
| 45° | ×1.414 | 41% more. Halfway to trouble. |
| 40° | ×1.556 | 56% more — half again as much. |
| 35° | ×1.743 | Three quarters more. |
| 30° | ×2.000 | Double. Each leg now carries the whole load’s weight. |
Where these come from. The factor is simply 1 ÷ sin(angle) — the same standard load angle factors printed on rigging charts and in the sling manufacturers’ handbooks. Check it against your own rigging chart; a chart for your specific sling is the authority, not this page.
What this does not know
- Where the weight sits. The maths assumes the load is balanced between the legs. Off-centre, one leg takes more — sometimes nearly all of it. Use the centre of gravity tool for that.
- Legs of different lengths. The short leg takes the load first.
- What the sling is wrapped around. Choker and basket hitches, sharp corners, and the D/d ratio all change what a sling may carry. That is on the sling’s own chart.
- Shock, wind and side pull. Snatching a load adds far more than the numbers here.
- Anything about a particular crane. This is rigging maths only. What the machine may lift is on its load chart.
Rounded up, never down. A tension rounded down flatters exactly the lift that is already at its limit.