Standard Bollard Sizes & How to Measure for the Right Bollard Cover

Key Takeaways

• The name on the pipe is not the measurement that matters: a 4" bollard has a 4.5" outside diameter, and the cover fits the OD, not the name.
• Measure the pipe, not the label: wrap a tape around the bollard, divide by 3.14, and you have the number that actually matters for ordering a cover.
• 1/4" heavy duty covers take the hits: forklifts, loading docks, and anywhere vehicle contact is a regular occurrence.
• 1/8" standard covers are the right call when the bollard is marking a boundary rather than stopping a vehicle.
• Custom cut lengths ship at no extra charge: measure the actual post height before ordering, not a standard dimension you think it might be.

Table of Contents

1. Standard Bollard Sizes: What to Know
2. How to Measure for the Right Bollard Cover
3. Bollard Cover Options: 1/4" vs 1/8" Wall
4. Why Choose Bollards & Sleeves?
5. Final Thoughts
6. Frequently Asked Questions

Ordering a bollard cover sounds straightforward until the package arrives and the cover does not fit. The most common reason is measuring the nominal pipe size instead of the outside diameter. A 4" bollard is not 4" wide. A 6" bollard is not 6" wide. The nominal size is a designation: the actual outside diameter is always larger, and the cover fits the OD, not the name.

This guide covers standard bollard sizes, how to measure correctly, and which cover wall thickness belongs on which application. Get these three things right and the cover fits the first time.

1. Standard Bollard Sizes: What to Know

Steel pipe bollards are sized by nominal pipe size (NPS): a standardized designation that does not directly correspond to the actual pipe diameter. Understanding bollard sizes correctly starts here, because the outside diameter is always larger than the nominal size. This matters because bollard covers and pipe bollard covers are designed to fit the outside diameter, not the nominal designation.

The typical bollard size for commercial applications is 4" or 6" nominal pipe: 4.5" and 6.625" OD respectively. Schedule 40 and Schedule 80 refer to wall thickness, not diameter. A 6" Schedule 40 and a 6" Schedule 80 have the same OD (6.625") and take the same bollard cover.

2. How to Measure for the Right Bollard Cover

Getting the right bollard dimensions before ordering a cover takes two measurements: outside diameter and height. Knowing the bollard sizes table above is helpful, but measuring the actual post is always more reliable than assuming the nominal designation is correct.

Step 1: Measure the Outside Diameter

Wrap a flexible tape around the bollard and measure the circumference. Divide that number by 3.14 and you have the outside diameter. Calipers across the widest point work too. What you should not do is go by the nominal pipe size: a pipe labeled 4" is actually 4.5" across. Order the cover by OD and it will fit. Order by nominal size and it probably will not.

Step 2: Measure the Height

Measure from the ground up to the top of the post. That is the height the cover needs to reach. If the bollard sits on a base plate that raises it above floor level, start your measurement from the top of the plate, not the floor: the cover sits on the plate, not through it. Taller than standard? Custom lengths are available at no extra charge.

Common Measuring Mistakes

• Going by the nominal pipe size instead of measuring the OD: the cover ships, arrives, and does not fit.
• Measuring from the floor when the bollard is raised on a base plate: the cover comes out too long and overhangs.
• Assuming the bollard is a standard height when it has been cut shorter: measure what is actually there, not what you think it should be.
• Forgetting the top cap adds to the cover height: the listed cover height includes the dome or flat top, so the exposed pipe coverage is slightly less than the total dimension.

Not Sure Which Size? Call Us.

1-800-914-4771 or email sales@bollardsleeves.com. We will confirm the right size before the order ships.

3. Bollard Cover Options: 1/4" vs 1/8" Wall

Once the diameter and height are confirmed, the remaining choice is wall thickness. Bollards & Sleeves carries two options for pipe bollard covers: 1/4" heavy duty and 1/8" standard. The right one depends entirely on what the bollard is protecting against.

1/4 Inch Heavy Duty Bollard Covers

The 1/4" wall is built for environments where vehicle contact is expected. Warehouses in Ohio and Michigan where forklifts operate near bollards, loading docks in Texas where trucks back in daily, manufacturing facilities in Illinois where heavy equipment moves through tight corridors. The thicker wall absorbs contact without cracking or compressing and holds its shape through repeated hits.

1/8 Inch Standard Bollard Covers

The 1/8" wall suits locations where the bollard is doing visibility and delineation work rather than absorbing vehicle contact. Storefronts in California, pedestrian walkways in New York, parking lot perimeters in Georgia where the primary job is marking the boundary rather than stopping a vehicle. Lighter wall, same LDPE material, same UV and anti-static additives, same color-through-the-material construction.

4. Why Choose Bollards & Sleeves?

Bollards & Sleeves supplies steel pipe bollards across all standard bollard sizes from 3" to 10", with covers to match every bollard size in stock. All American-made. Custom cut lengths ship fast.

• Every standard bollard size in stock: 3", 4", 6", 8", and 10" in Schedule 40 and 80, ready to ship.
• 1/4" heavy duty covers: For forklifts, loading docks, and anywhere the bollard takes regular vehicle contact.
• 1/8" standard covers: For storefronts, pedestrian zones, and anywhere appearance is the priority.
• Custom cut heights at no extra charge: Order the exact height you need, not whatever happens to be standard.
• Finishes: Bare pipe, primed, powder coated, and galvanized.
• Multiple shipping locations: Competitive freight pricing across the US.

5. Final Thoughts

The right bollard cover starts with the right measurement. Outside diameter, not nominal size. Actual post height, not a standard dimension. Wall thickness matched to what the bollard is actually doing. Get those three right and the cover fits, does its job, and lasts. Get any one wrong and the order comes back.

Know Your Size? Order Your Bollard Cover Today.

Call 1-800-914-4771 or email sales@bollardsleeves.com. Bollard covers in stock and shipping fast.

6. Frequently Asked Questions

Q1: What are the standard bollard sizes?

A: 3", 4", 6", 8", and 10" nominal pipe: those are the standard options. The typical bollard size for most commercial sites is 4" or 6". Outside diameters run from 3.5" up to 10.75". The cover fits the OD: measure that, not the nominal size printed on the pipe.

Q2: How do I measure for a bollard cover?

A: Wrap a tape around the pipe and divide the circumference by 3.14: that is the outside diameter. Then measure from the ground or base plate to the top of the post. Two numbers, and you have everything you need to order the right pipe bollard cover.

Q3: What is the difference between 1/4" and 1/8" bollard covers?

A: The 1/4 inch heavy duty bollard cover takes the hits: forklifts, loading docks, industrial facilities where something is going to make contact eventually. The 1/8 inch standard bollard cover is for marking and visibility where contact is unlikely. Same LDPE material, same color-through construction: the only difference is how much wall is between the post and whatever hits it.

Q4: Do bollard covers fit both Schedule 40 and Schedule 80 pipe?

A: Yes. Schedule is wall thickness, not diameter. A 6" Schedule 40 and a 6" Schedule 80 are both 6.625" OD: same bollard cover, different amount of steel in the wall. Order by OD and both pipe schedules are covered.

Q5: Can bollard covers be cut to a custom height?

A: Yes. Custom cut heights are available at no additional charge. Measure the actual post height and specify it when ordering: do not assume a standard height will fit a bollard that has been cut to a non-standard length.