How to Read a Forklift Load Capacity Chart

Understanding a forklift’s load capacity is not as simple as reading the maximum capacity and jumping to work - many factors influence how much a fork truck can lift at a specified height. Should an operator exceed their forklift’s rated maximum capacity, it can put their safety at risk. That's why it's crucial for forklift operators to understand how to read a forklift load capacity chart.

How is a forklift’s load capacity defined?

A forklift’s load capacity is defined as a specific weight at a specific load center. While your forklift may be rated to lift 6,000 pounds, that maximum capacity can be reduced based on the shape of the load you are moving. Objects with longer load centers cannot be as heavy as shorter objects due to the physics involved with forklift counterweights. The maximum capacity of a forklift is negatively affected by larger load centers, higher lifting heights, attachments and other factors. 

What is a forklift data plate?

A forklift data plate contains essential information about the forklift, such as its rated maximum capacity, model and serial numbers, attachments, etc. Some manufacturers include the load capacity chart as a table giving the maximum weight lifted at different mast stages for different load centers. Others provide this information as a chart to highlight the differences between the different factors. Being able to locate the maximum capacity, load center dimensions, and load height are essential for safe operation of the forklift. 

Below is an example Clark forklift data plate. We picked Clark because it's one of the top 10, best-selling forklifts in the world.

Clark Forklift Data Plate Explained

1. The top row tells us the model number (C20SCL), Type (propane - "LP") and the unit's unique Serial Number.

2. The second row indicates this lift truck has an attachment, an SS20180. The letters "SS" stand for side shifter and the "20180" indicates the model number.  The forklift could also have an "RC" (roll clamp), "CC" (carton clamp) and so on.

It may seem strange to list the attachment on the data plate when you can just look at the forklift and see there's an attachment. But because attachments and other modifications can affect the forklift's maximum capacity, OSHA requires an updated data plate.

3. The rearward tilt is 5 degrees, meaning the mast can tilt a maximum of five degrees toward the operator. 

4. This section describes the forklift's tires. This fork truck has cushion tires that are 37 inches wide. If "PSI" appeared on this data plate, that means the forklift uses pneumatic tires and the PSI number is the recommended tire pressure.

5. At the bottom left you can see how much the truck weighs. If this was an electric forklift, there would be information about the battery.

6. This section is the all important load capacity chart.

How to Read a Forklift Load Capacity Chart

There's a "24" to the right of letters A and B. This number describes the positioning of the load center. Based on the diagram, this forklift has a load center  measured from the front of the forks (A) and vertically from the top (B). 

The load center is, as you may have guessed, the center of gravity for the load. The forklift's maximum capacity (3550 lbs.) is for a centered load as shown in the second diagram, labeled "D."

Sometimes you'll see additional information in the chart for different load centers. Generally speaking, as A and B increase, the maximum capacity decreases.

The letter C indicates the maximum lift height. On this truck, it's 188 inches.

One last thing. The maximum capacity for this Clark forklift when it came from the factory was 4000 lbs. But as you can see, the maximum capacity is only 3550 lbs. This is because of the forklift attachment.

How are forklift load capacities regulated?

Both OSHA and ANSI require that each forklift attachment has its own data plate. They also require written approval to be secured from the forklift manufacturer for any after-market modifications that can affect the equipment’s capacity, stability, and safe operation. 

ANSI B56.1 Section 7.6.3 provides two methods for forklift manufacturers to calculate a forklift’s capacity. The maximum capacity can be calculated based on various factors, such as lift heights, load centers, attachments, and other factors. The second requires forklifts to be chained to a tilt table and tested according to guidelines in ANSI B56.1 Section 7.6.4. 

What are best practices for forklift load capacities?

Maintaining accurate documentation of your fleet’s rated capacities is essential for the safety of your warehouse, equipment, and employees. Some other best practices include:

• Purchasing forklifts with rated load capacities just above your expected needs to future-proof your fleet.
• Implementing training programs for your operators to ensure foundational safety skills are part of your culture.
• Make scales available to weigh loads if they are not already marked. 
• Stress the importance of reducing load weights in load centers are larger than usual. 
• Ensure data plates are present, accurate, and easily readable. 

The potential damage and harm from exceeding a forklift’s rated load capacity is devastating. Building a culture of safety that includes understanding how to read a forklift load capacity chart and how to apply that information to your daily operation is essential for keeping your workplace and employees safe.

Further Reading:
Remote or On-Site Forklift Operator Training Classes
Popular Forklift Attachments in Washington State
Forklift Attachments and Modifications: What Does OSHA Require?