where do you find the capacity of your forklift

Executive summary

A forklift’s “capacity” is not a single number.  It is a family of weight limits that change with mast height, load geometry, attachments and even tire pressure.  The only place all of these variables are tied together in one spot is the forklift data plate (sometimes called capacity plate, nameplate or data tag).  This article walks through every field on that plate, explains why the published “5,000 lb” figure rarely tells the whole story, and shows you where else to look—on the truck and in the technical file—when the plate is missing, defaced or obsolete.

The data plate: primary source of truth

1.1 Regulatory anchor

OSHA 29 CFR 1910.178(a)(3) and ANSI B56.1 require every powered industrial truck to have a “permanently affixed nameplate that is corrosion-resistant and legible”.  The plate must be updated every time an attachment is added or the truck is re-rated.  If the plate is illegible, the truck is legally out of service.

1.2 Physical location

• Counter-balance trucks: upper right side of the overhead guard frame, facing the operator.

• Reach trucks & order pickers: on the mast cross-beam or battery compartment door.

• Rough-terrain forklifts: left-hand cowl near the operator station.

Tip: When you walk up to an unfamiliar truck, shine a flashlight on the overhead guard first; the plate is usually riveted or glued with tamper-proof sealant.

1.3 Anatomy of a modern data plate (example below)

Field Typical content Why it matters

Model & Serial No. C20SCL-12345 Links to the OEM parts & capacity book

Power type LP / Electric 48 V / Diesel Battery or fuel weight affects net capacity

Mast type 3-stage 188" MFH Capacity drops as mast height increases

Attachments SS20180 sideshifter OSHA requires separate de-rating

Tire spec 6.50×10-10PR Pneumatic vs cushion changes stability base

Truck weight 8,680 lb Needed for floor-loading calculations

Load chart 5,000 lb @ 24" LC, 130" lift 4,500 lb @ 24" LC, 156" lift The actual numbers you work with

A blank template of a data plate is shown in Figure 1 (omitted here for brevity).  Each manufacturer arranges the table slightly differently, but every plate contains at least:

A. Rated capacity (single or table)

B. Load center (standard 24" in North America, 500 mm in Europe)

C. Mast stage or lift height at which the capacity applies

D. Attachment de-rate if installed.

1.4 How to read a capacity chart

On the plate you will usually see two small diagrams: a side view and a top view.  Letters A, B, C, D correspond to columns in the table:

• A = horizontal load center (distance from fork face to center of gravity).

• B = vertical load center (rarely used, normally equal to A).

• C = maximum fork height at that capacity.

• D = lateral offset (off-center loads).  If the D column shows “0”, the truck is not rated for side-shifted loads.

Example: Clark C20SCL plate

At 24" load center, 188" lift height → 3,550 lb.

Factory rating without attachment → 4,000 lb.

The 450 lb reduction is due to the sideshifter.  If you remove the attachment but keep the original plate, the truck is technically over-rated and the plate must be replaced.

2. Secondary locations when the plate is missing or obsolete

2.1 Maintenance logbook

OSHA requires a “permanent record” of any change to capacity.  Most fleets keep a copy of the original “Certificate of Rating” in the service file.  Ask the fleet manager for the truck serial number folder.

2.2 OEM parts & capacity manual

Every forklift ships with a handbook that contains a page titled “Capacities and Load Diagrams.” This is the only authoritative source for oddball combinations—e.g., 4-stage mast, 72" fork extensions, quad tires.  Downloadable PDFs are usually free on the manufacturer’s website once you enter the serial number.

2.3 Mast channel stamping

Some brands (Crown, Toyota) stamp the base capacity on the inside of the outer mast channel near the floorboard.  The number is small and appears as “5000 @ 24” or “3500 @ 500”.  This is a backup reference, not a compliance plate.

2.4 Attachment nameplates

Each attachment (paper roll clamp, carton clamp, fork spreader) must have its own plate stating weight and residual capacity.  The lowest of the truck and attachment ratings governs the lift.

3. Dynamic factors that change the number on the plate

3.1 Load center vs. actual load

If you pick up a 60" long pallet instead of the standard 48", the center of gravity moves from 24" to 30".  Capacity falls in direct proportion:

Actual capacity = Rated capacity × (Rated LC ÷ Actual LC)

Example: 5,000 lb truck at 24" → 5,000 × 24/30 = 4,000 lb.

3.2 Lift height

As the load is raised, the moment arm between load and fulcrum grows.  A forklift rated 5,000 lb at 130" may only handle 4,200 lb at 188".  The chart on the plate gives the precise curve.

3.3 Attachments

Every 100 lb of attachment weight removes 100 lb of payload, but the static moment also shifts forward.  Manufacturers apply a de-rating factor (often 10–15 %) on top of the dead weight.  That is why a 200 lb sideshifter can reduce capacity by 300-400 lb.

3.4 Tire condition

A pneumatic tire that is 20 % under-inflated lowers the truck’s stability triangle and effectively reduces capacity by 2–3 %.  Solid tires with severe chunking have the same effect.

3.5 Battery state (electric trucks)

A discharged lead-acid battery weighs up to 4 % less than a fully charged one.  While this is small, on a 3,000 lb battery that is 120 lb of lost counterweight—enough to tip the margin if you are already at 98 % of chart capacity.

4. Step-by-step: how to determine the capacity you can use today

4.1 Walk-around inspection (30 s)

• Is the data plate present, legible and matching the installed mast/attachment?

• Any fresh welds or bolt-on modifications?  If yes, stop and call service.

4.2 Identify load center of the pallet you will lift (15 s)

Measure the pallet length; divide by 2.  Add any overhang from product.

4.3 Read the plate (15 s)

Find the row where A (load center) ≥ actual load center and C (lift height) ≥ required lift.

4.4 Apply attachment de-rating if not already on plate (10 s)

Subtract attachment weight and use OEM multiplier if provided.

4.5 Quick field de-rate (10 s)

If tires are questionable, battery low, or floor surface uneven, reduce by 5 %.

4.6 Document

Record the calculated capacity on the daily inspection sheet or electronic system.  If the load exceeds the calculated value, split the load or use a larger truck.

5. Digital tools and calculators

When the geometry is complex (e.g., dual-pallet handler, 4-stage mast, high stacking), use the OEM online calculator.  Most require four inputs: model, mast stage, actual load center and lift height.  The output is printable and can be taped to the dash as a temporary label.

6. Fleet-level best practices

• Color-code trucks: Green label = standard 24" LC, Yellow = reduced capacity, Red = special attachment.

• Re-plate after every significant repair (mast rebuild, counterweight swap).

• QR codes: Some fleets attach a weather-proof QR code next to the data plate; scanning it opens the current load chart PDF on a phone.

• Training: Include a 5-minute “find the capacity” drill in every operator recertification session.

7. Common myths—debunked

Myth 1: “The sales brochure says 6,000 lb, so I can lift 6,000 lb of anything.”

Reality: Brochure rating is at 24" LC, 197" lift, no attachment.  Real conditions often drop the safe figure by 15–30 %.

Myth 2: “If the attachment is removed, the original plate is still valid.”

Reality: OSHA treats any alteration as requiring a new plate—even when capacity increases after removal of an attachment.

Myth 3: “A 5,000 lb forklift weighs 5,000 lb.”

Reality: Service weight is always higher—often 1.5–2× the rated capacity.  The plate lists both numbers separately.

8. Summary checklist (printable)

I have located the data plate and confirmed it is legible.

The plate lists the correct mast and attachment currently on the truck.

I have measured the actual load center and compared it with the plate.

I have applied any attachment or height de-rating.

The calculated capacity is greater than the load I intend to lift.

The calculation is documented on today’s inspection form.

If any box is unchecked, stop the lift and contact supervision.

9. References

: BigRentz, “Forklift Capacity: Definition and How To Calculate It,” 2023-04-12

: Conger Industries, “Forklift Weight Capacity: Everything You Need to Know,” 2024-10-28

: Midco Forklift, “How to Read a Forklift Load Capacity Chart,” 2025-02-05

: Total Warehouse, “Forklift Weight Capacity – How Much Do You Need?,” 2024-05-24

: OSHA eTool, “Powered Industrial Trucks – Nameplate,” accessed 2025-07-18

By following the steps above, you will always know exactly where to find—and how to interpret—the capacity of your forklift under real-world conditions.