Rigging Weight Calculator
Estimate the load, rigging hardware, sling or chain weight, center-of-gravity allowance, and contingency weight before a lift plan review.
⚙Rigging Presets
📏Load And Rigging Inputs
Rigging weight snapshot
Enter load and rigging data to calculate the planning weight.
📊Material And Hardware Spec Grid
📘Rigging Reference Tables
| Material | Density | Metric | Typical use |
|---|---|---|---|
| Carbon steel | 490 lb/ft3 | 7,850 kg/m3 | Plate, beams |
| Stainless steel | 500 lb/ft3 | 8,000 kg/m3 | Tanks, pipe |
| Aluminum | 169 lb/ft3 | 2,710 kg/m3 | Frames, tanks |
| Concrete | 150 lb/ft3 | 2,400 kg/m3 | Blocks, barriers |
| Dense timber | 35 lb/ft3 | 560 kg/m3 | Crates, dunnage |
| Hardware | Weight | Best input | Note |
|---|---|---|---|
| 5/8 shackle | 1.8 lb | Each | Light picks |
| 1 in shackle | 7.5 lb | Each | Common crane |
| 1-1/2 shackle | 24 lb | Each | Heavy links |
| Hook block | 240 lb | Kit | Medium crane |
| Spreader beam | 420 lb | Kit | Long loads |
| Sling type | Weight | Metric | Common use |
|---|---|---|---|
| 1/2 wire rope | 0.48 lb/ft | 0.71 kg/m | Light sets |
| 3/4 wire rope | 1.06 lb/ft | 1.58 kg/m | General lifts |
| 1 in wire rope | 1.85 lb/ft | 2.75 kg/m | Heavy lifts |
| 1/2 alloy chain | 2.6 lb/ft | 3.87 kg/m | Adjustable legs |
| Large round sling | 0.75 lb/ft | 1.12 kg/m | Soft contact |
| Allowance | Typical | Use when | Check |
|---|---|---|---|
| Known COG | 5% | Balanced load | Lift points |
| Offset COG | 10% | Skids, tanks | Trial lift |
| Unknown internals | 15% | Machinery | Tag data |
| Poor data | 20% | Old equipment | Scale weight |
| Critical lift | Plan review | High risk | Engineer |
💡Rigging Weight Tips
A rigging weight calculator is a tool that helps a person to determine the total weight of the load that is to be lifted. While many people has an idea of the size of the load that they are about to lift, few people may know the total weight of that load and the rigging that will be used to lift that load. If the total weight of the load and the rigging gear are not known, then the lift plan can not be certain as to how the load will be lifted.
A rigging weight calculator helps to reduce this uncertainty in the planning of a lift by calculating the total weight of the load and the rigging gear that will be used to lift that load. The rigging weight calculator will include the total weight that is calculated, the weight of the object that is to be lifted, the weight of the rigging hardware that will be used to lift that object, and the total weight of any allowance that may be added to those components of the total weight. In order to calculate the total weight of the object that is to be lifted by the rigging gear, the rigging worker must first decide the shape of the object that is to be lifted.
How to Use a Rigging Weight Calculator
The shape of the object will determine the total volumes of the object. For instance, a solid block of steel will have a different volume than a hollow tank shell of the same outside dimensions. Once the worker has selected the shape of the object, the worker must also select the density of the material of the object.
For instance, carbon steel has a density of 490 pounds per cubic foot while aluminum has a density of 169 pounds per cubic foot. These values will allow the rigging weight calculator to determine the weight of the object. The rigging hardware will have a significant portion of the total weight of the load.
The rigging weight calculator will account for the total weight of hardware such as hook blocks, spreader beams, shackles, and slings. Each of these component may be separated within the weight calculation so that the rigging worker can determine which component of the rigging system has the most weight to it. If the total weight of the rigging hardware is too great for the object that is to be lifted, then the choice of rigging hardware may be altered.
The weight of the slings will also be accounted for within the calculation of the total weight of the load. The type of material of the slings will impact the weight of those components, as will the length of the slings. For instance, a wire rope sling will weigh more than a synthetic round sling of the same length.
In addition, the longer the slings, the more weight that they will add to the total weight of the load. If the object that is to be lifted has attachment points that are far from each other, then longer slings will be required. A load is not always balanced in such a way that the center of gravity of the load is directly below the crane hook that is to be used to lift that load.
In these instances, allowances must be made for the offset of the center of gravity of that load. In documented situations, a five percent allowance may be made for the offset of the center of gravity. In situations in which the contents of the load are not documented, however, a fifteen or twenty percent offset allowance should be made for the potential for the center of gravity of the load to not be directly under the crane hook.
The rigging weight calculator will allow for these allowances to be made in the calculation of the total weight of the load. A contingency percentage is also made within the rigging weight calculator. The contingency percentage will include an extra amount of weight to that calculation.
This extra weight accounts for potential additional loads on the components of the rigging, such as if the tag line becomes snagged or if the size of a shackle change. This percentage will indicate the total weight of the load that the crane will account for. If the total calculated weight from the rigging weight calculator exceeds the weight of the load that is allowed by the chart for the crane, then the lift plan will need to be altered before beginning the lift.
The reference tables included in the rigging weight calculator are used to determine various values regarding the load to be lifted. For instance, these tables can be used to determine the weight of slings of various lengths, the mass of shackles of different sizes, and the densities of various materials. These references help to make clear the reason that certain allowances are to be made within the total weight of the load.
For instance, the tables will indicate that a load that is expected to be balanced will have a lower allowance for the offset of the center of gravity of the load than a load whose internal components are not documented in advance. In general, many people make mistakes when using the rigging weight calculator. For instance, some individuals may only input the dimensions of the object that is to be lifted, but fail to account for the weight of the hardware that will be used to lift that object.
In other instances, the mistakes may include the inclusion of the weight of the rigging but incorrectly applying the contingency percentage to that total weight. In each instance, the individual should pay attention to the different weights that are accounted for in the calculation of the total planning weight. For instance, if the weight of the slings is found to be too great, then that portion of the load may be altered.
If the weight of the object is found to be too low, then the density of the object or the thickness of that object may be altered. While the rigging weight calculator is unable to account for the effects of the wind or the temperature of the environment in which the object is to be lifted, the calculation does help to account for the unknown variables of the lift. If the total weight that the rigging weight calculator calculates is close to the weight limit of the crane that will be used, then it is recommended that the weight of the load is verified with a scale.
The output of the rigging weight calculator should be the total weight that is accounted for during the lifting of the load. Any changes to the material of the object that is to be lifted, for instance, or the addition of a hardware component like an extra shackle, should be instantly reflected within the rigging weight calculator software. If used correctly, the total weight that the rigging weight calculator calculates will be the total weight of the load that is actualy lifted by the crane.
