What Is a Bankers Box? What Size Is a Bankers Box? A 7-Step Storage Checklist

If you're reading this because someone just told you "we need the files in bankers boxes by Friday," I know what that feels like. I coordinate records-storage supply orders for a records-management company, and in the past six years I've processed about 200 rush orders. Some of those needed to turn around in less than 24 hours. The mistakes are almost always the same, and almost always avoidable.

This is a 7-step checklist for choosing the right bankers box, in the right size, without turning a simple storage project into a last-minute overnight delivery.

What Is a Bankers Box?

A bankers box is a corrugated fiberboard storage box designed for files and records. The name comes from the original product used by banks to archive paper documents: a sturdy box with a separate lid, reinforced side panels, and a front panel that can be labeled. The design became so common that "bankers box" is now used generically for records-storage boxes of the same format.

It's tempting to think a box is a box. But corrugated strength, internal dimensions, and lid design can vary enough to cause real problems. A box that's too weak will sag under weight. A box that's a half-inch too short will bend the files you're trying to protect.

The 7-Step Checklist

Step 1: Measure the files you're storing

Start with the contents, not the shelf. Measure the actual width, length, and height of the files you intend to pack. Standard letter-size folders are 8.5" x 11", but a packed hanger folder can be wider. Legal folders are 8.5" x 14". Binders need a whole different depth.

What most people don't realize is that "standard" in this industry isn't a universal spec. One manufacturer's letter-size box can be narrower inside than another's. The label might say letter, but your bulky file might not fit. So always compare the interior dimensions of the box against your measured files.

Step 2: Measure the space for the boxes

Now measure the shelf opening or floor area where the filled boxes will go. If using shelving, measure height, width, and depth. Leave at least an inch of clearance around the box so you can pull it in and out. I've seen a client order 50 boxes that were exactly one inch too tall for their storage cart. They ended up storing the boxes on the floor, blocking a fire exit, until we found an alternative. That's a conversation you don't want to have.

Step 3: Choose a box style that matches the job

There are three main styles:

• Separate-lid boxes. The classic choice for long-term storage. The lid keeps out dust and adds structural support when stacking.
• String-and-button boxes. Cheaper and quick to fold, but the string closures can wear out if you open and close them often.
• Open-top boxes. Good for active files, but not for archiving.

For records you plan to keep for years, I'd use a separate-lid box. It's a small price difference for a meaningful amount of protection.

Step 4: Identify the right size—and answer "what size is a bankers box?"

If you're asking what size is a bankers box, the quick answer is: it depends, but there are common patterns.

• Letter-size bankers boxes are typically around 15" long x 12" wide x 10" high on the outside. The inside is smaller because of the corrugated walls.
• Legal-size boxes are longer (and sometimes slightly taller) so that 8.5" x 14" documents stay flat.
• Other sizes exist for things like computer printouts, binders, or index cards.

I want to say "15 x 12 x 10" is the universal answer, but don't quote me on that. Check the manufacturer's spec sheet before ordering. If you're buying from an office supply site, the interior dimensions are usually listed. If they're not, call. Hiring a human for two minutes is cheaper than reordering 40 boxes.

Step 5: Think about weight, stacking, and humidity

A full records box can weigh 35 to 40 pounds. Stack four high, and the bottom box is supporting a lot of weight. Look for boxes with adequate strength—200 lb test corrugated is a common benchmark for heavy records storage. Also, pay attention to the environment. Corrugated boxes absorb moisture. If your storage room is damp, the boxes will eventually soften and sag, no matter how good the brand is. A desiccant dehumidifier can keep that air dry enough to protect both the box and the paper inside. (Yes, I'm talking about humidity in a box article. I've seen what a humid basement does to 100 "fine" boxes in four months.)

Step 6: Order a buffer before you need it

Add 10–15% to your calculated quantity. If you think you need 30 boxes, order 33 or 35. That buffer is a tiny part of the overall cost, and it prevents a very expensive problem.

In March 2024, a client called at 8am needing 15 boxes for a transfer the next morning. Their normal supplier could deliver in three business days. The only overnight option came with $180 freight on a $90 box order. If they had ordered 3 extra boxes at the beginning, they would have spent about $15 extra—not $180.

When I'm triaging a rush order, the first question isn't "how many boxes?" It's "what's the deadline?" Because if you have three days, standard shipping is fine. If you have one day, you're paying for someone's urgency.

Step 7: Compare total cost, not just unit price

A cheap box seems like a good deal until it collapses and you have to rebox 500 files. I learned that lesson in 2023 with a budget batch of 40 boxes. The price was $0.80 less per box than the option I usually buy. The savings: $32. The cost when six boxes buckled under normal stacking: around $400 in labor to transfer the files, plus the $90 for new boxes. $32 of savings turned into a $500 problem. That's the "low price" trap.

I'm not saying cheap boxes are never the right choice. If you just need temporary containers for a one-day move, a budget box is fine. But for archival storage, buy for the total cost of ownership: unit price + shipping + handling time + failure rate. A good box is not a place to save pennies.

Common Mistakes to Avoid

• Using outside dimensions to judge whether files fit. Always use inside dimensions.
• Overfilling. If you have to push down to make the lid fit, you have too much in the box.
• Ignoring the bottom of the box. The bottom can separate if the box is carried from the bottom too often. Look for boxes with a strong self-locking bottom or steel stitching.
• Storing directly on a concrete floor. Concrete releases moisture. Use a pallet or shelf to get boxes up off the floor.

The Bottom Line

What is a bankers box? It's a simple, proven way to store records. What size is a bankers box? Most of the time, the letter-size or legal-size version will do the job—but only if you measure first.

If you take nothing else from this checklist: measure the files, measure the space, check the inside dimensions, order a small buffer, and choose quality over the smallest number. That's how you keep a routine storage task from becoming an emergency.