The Best Truck Tool Box: Every Type Compared and How to Choose

What is the best truck tool box?

For most work trucks, a crossover box mounted behind the cab is the best choice — it gives the most secure, weather-resistant capacity per dollar without costing you usable bed length. If you regularly haul lumber, pipe or pallets and need the bed floor completely clear, a topside box is the better call. And if you can't spare any bed space at all, an underbody box mounts to the frame below the bed and uses none.

That's the short answer. The honest one is that it depends on three things: how your bed is configured, what you actually haul, and how the truck gets used day to day. Get those straight and the choice narrows fast. Get them wrong and you've swapped one problem for another — secure storage, and nowhere to lay the lumber.

Jump to: Our picks · Find your use case · Crossover · Topside · Underbody · Chest · Materials · Measuring · Mounting · FAQ

Our picks

Why the CamLocker is our default. It's the crossover our customers choose more than any other, and the reason is the latch. Most boxes in this class close with a low-grade paddle handle — the part that flexes under a pry bar and the first thing to fail. CamLocker uses revolving cams that hook through welded catches, so getting in without a key means breaking the lid or bringing power tools. Add .063 polished aluminum welded construction, full-length stainless hinges, insulated weather-sealed lids, removable sliding trays and a 3-year structural warranty. If you don't have a specific reason to buy something else, buy this.

Find your use case

There are four basic types, and they're defined by where the box mounts: across the bed rails, on top of the bed wall, under the bed on the frame, or down on the bed floor. Get that right and the rest is detail.

1. Crossover boxes

Mounts across the width of the bed, tight against the cab, with a lid that opens upward. The most widely adopted box on the road and the best capacity per dollar.

Best for: daily-use service trucks and mixed-use fleets. Mounting tight to the bulkhead preserves the rest of the bed floor for long or bulky cargo.

The trade-off: you reach down into a tub, so anything at the bottom means digging. It also commits the front two feet of your bed permanently.

The three specs that matter

Profile. Standard profile stands higher above the rails for more storage. Low profile sits lower so it stays out of your rear-view line. Both mount on the bed rail at the same height — the difference is how far up they stand from there.

Tub shape. The tub is the part that hangs down into the bed. Standard is rectangular and fits the widest range of beds. Deep adds height for volume, if you have the room below. Notched or angled is cut away at the bottom corners to clear wheel wells and sloping bed walls — which matters most on short beds, where the wheel wells sit close to the cab, and on deep tubs that hang far enough down to reach them.

Latch. A single-point paddle handle on a long lid lets the ends flex, both under a pry bar and against the gasket. A cam, rotary or multi-point system pulls the lid down evenly along its full length. This is the single biggest difference between a cheap box and a good one.

One terminology note: on a crossover, length is the measurement across your bed rail to rail, and width is front to back. A 72-inch box is 72 inches across your bed, not 72 inches deep.

• CamLocker 71-in, Standard Depth — from $802.24. Our pick
• CamLocker 71-in, Deep Notched — from $881.67. Clears the wheel wells
• CamLocker 71-in, Deep — from $881.67. More volume
• UWS 72-in, Low Profile, Deep Angled Tub — $680.95. The value option

→ Browse all crossover boxes

2. Topside boxes

Mounts on top of the bed wall with a vertical door hinged at the top. The bed floor stays completely open.

Best for: anyone hauling flat or rigid material where a clear floor is a requirement, not a preference. Also the standard on flatbeds, duallies and service bodies, which have no conventional bed wall for a crossover to clamp to — usually specified in matched driver- and passenger-side pairs.

Why people switch: you reach your tools standing beside the truck instead of climbing into the bed. Once techs try it, most don't go back. It's the category our customers buy more of than any other.

The trade-off: narrow. Great for long tools, conduit, levels and pipe wrenches. Bulky items won't fit.

• Brute Top Mount Hi-Side — from $900.13, with top door plus bottom door or bottom drawer. Our pick
• UWS 72-in Double-Door Topside — $999.95
• UWS 48-in Single-Door Topside — $631.95
• Dee Zee 72-in Aluminum Top Mount — $892.96

→ Browse all topside boxes · Side mount boxes · Wheel well boxes

3. Underbody boxes

Mounts beneath the bed on the frame rail. Zero bed space used, the weight sits low where it doesn't affect handling, and you access it at ground level. The standard on flatbeds, dump bodies and trailers.

The trade-off: hardest install of the four, and mounting brackets are usually sold separately. That's the most common surprise on an underbody order.

Our pick: Buyers 60 x 24 x 24 Smooth Aluminum, Double Barn Door — $1,064.69. Three reasons. The barn doors matter most on a box this size: a 60-inch drop-down door means bending over a five-foot panel to reach the back, and it swings into whatever's parked beside you. The cam lock rod pulls both doors evenly against the seal rather than clamping at one point. And smooth aluminum won't rust, which counts on a box living in the road spray where you'd never see a chip start.

• Brute Underbody with Top Drawer & Bottom Door — from $675.99. The top drawer keeps small parts reachable instead of buried
• Buyers 48 x 18 x 18 Black Steel — $463.09. The budget workhorse
• Buyers 24 x 14 x 12 Diamond Tread Aluminum — $399.95. Compact and rust-free

→ Browse all underbody boxes · Mounting brackets

4. Chest boxes

Sits down on the bed floor rather than mounting to the rails. Deep rather than wide, and the easiest install of the four — often none at all beyond securing it.

Best for: short-bed trucks that still need capacity, securing generators and bulky equipment that needs depth, and anyone who wants storage that lifts back out when the bed is needed. A chest also works on a trailer or in the shop, which none of the others do.

Two shapes worth knowing: a standard chest is rectangular, and a wedge is angled at the bottom to clear wheel wells and other bed accessories.

One consideration: a chest sits high on the bed floor rather than low on the frame, so a heavily loaded one raises your centre of gravity more than an underbody box does.

• UWS 48-in Utility Chest — $711.95
• UWS 48-in Wedge Utility Chest — $642.95. Clears wheel wells
• UWS 42-in Utility Chest — $629.95
• UWS 36-in Foot Locker — $462.95. The compact option

→ Browse all chest boxes

Aluminum or steel?

Those are the two that matter, and nearly every box worth buying is one or the other.

Aluminum — around half the weight of steel, corrosion-resistant by nature, and the best strength-to-weight ratio. Dents more easily under a direct hit. Maintenance is an occasional wash. This is what most of what we sell is built from, and it's the default for good reason.

Steel — best impact and pry resistance, lowest cost, and the choice if the box is going to take real abuse. Heaviest, and the powder coat is the weak point: once it chips, rust starts and keeps going.

Salt state or watching payload? Aluminum. Taking a beating on a budget? Steel.

Compare wall thickness, not brand claims. CamLocker builds from .063 aluminum, the Brute underbody boxes from .100-inch diamond tread with a .125-inch reinforced bottom corner, and UWS crossover tubs from 0.058-inch one-piece aluminum. Those numbers tell you more than any marketing copy.

On finish: diamond tread hides scuffs and scratches far better than smooth or gloss black, while smooth aluminum looks sharper on a customer-facing truck.

How to measure — and which numbers you actually need

Here's the thing most guides get wrong: they hand you a list of bed measurements as if every box needs all of them. They don't. Which numbers matter depends entirely on where the box mounts. Find your type below and take just those.

Buying a crossover? Take four.

1. Across the bed rails — outside edge to outside edge, at the point the box will sit. This is the number quoted as crossover length. Full-size trucks typically take 69–72 inches; mid-size 54–63
2. Bed depth — floor to the top of the rail. The tub hangs down into that space, so this decides whether you can take a deep tub or need a standard one
3. Cab to wheel well — only matters on short beds. A crossover sits behind the cab, usually forward of the wheel wells, so on a long bed they're irrelevant. On a 5-foot bed, or with a deep tub that hangs far enough down, a square tub can foul them. That's what notched and angled tubs are for
4. Height above the rail, from the product spec — only if rear visibility matters to you. This separates standard profile from low profile, and it's about your mirror rather than whether the box fits

Buying a topside or side mount? Take two.

1. Bed rail length — front to back along the rail the box will sit on. This is the governing number, and it's the one people forget to take because they're used to thinking about bed width
2. Bed depth — these boxes can have legs that rest on the bed floor, so you need the drop to fall within the leg adjustment range

You do not need the across-the-rails measurement or the wheel well gap. A topside runs along one side and doesn't reach either.

Buying underbody? Forget the bed entirely.

This is a chassis measurement, not a bed measurement. Get under the truck with a tape:

1. Clear frame rail length — obstruction to obstruction. Note the fuel tank, DEF tank, exhaust, spare tire winch and air tanks
2. Available drop — from the bottom of the rail to the point where you stop being comfortable with ground clearance. Anything hanging below the frame's lowest existing point will find every driveway apron you own
3. Available width outboard of the rail — before the box protrudes past the body line

Buying a chest? One number does most of the work.

1. Between the inner bed walls, and between the wheel wells — a chest sits down on the floor, so this is what it has to fit inside. It's the governing number, and it's why wedge and notched chests exist
2. Bed floor length — how much room you have, and how much you're willing to give up
3. Floor to the top of the rail — if you want the chest to sit below the rail line for rear visibility

Whatever you're buying

Allow clearance for anything already on the truck: a ladder rack, headache rack, bed rail caps, a drop-in liner with a rail lip, or tie-down tracks. And send us your numbers if you'd rather have a second pair of eyes on them.

How they mount

J-bolt anchor kits are the standard for crossover and topside boxes — a hooked bolt catching under the bed rail lip or into a stake pocket, clamped with a plate and nut. No holes in your truck, and the box comes off cleanly when you sell it. Usually under an hour with a helper. This is what you want if you lease or care about resale.

Bolt-through mounts are more rigid and sometimes required on heavier commercial boxes. Every penetration needs sealing properly or you've created a rust starting point.

Underbody boxes are a different job. Budget two to four hours for your first one, less once you've done it. Use jack stands and a floor jack to hold the box while you start the fasteners, and check both sides of the frame rail for brake lines, fuel lines and wiring before the bit goes in. Use anti-seize at every dissimilar-metal contact point — an aluminum box against a steel bracket against a steel frame is a galvanic corrosion recipe if you leave it bare.

→ Mounting kits and accessories

Keeping it working

Four habits separate a box you replace in four years from one you keep for twelve:

• Rinse after road salt. Matters more than anything else on this list if you run winter roads
• Inspect the gasket annually. A tired gasket is the usual cause of a box that suddenly lets water in, and replacements are cheap
• Lubricate hinges and lock cylinders once a year. Marine grease on the pins, dry lubricant in the cylinder
• Re-check mounting torque after the first few hundred miles, then annually

Replacement locks, keys, latches and legs are available for most boxes, so a worn part doesn't mean a new box.

A tool box isn't the only way to add storage. If your problem is finding things rather than fitting them, look at bed drawer systems. Under-seat storage is the cheapest organized space you can add, using dead room in the cab. And ladder racks get long material out of the bed entirely.

FAQ

What are the basic types of truck tool box?
Four: crossover (across the bed rails behind the cab), topside (on top of the bed wall), underbody (below the bed on the frame), and chest (on the bed floor). Everything else is a variation on those.

Aluminum or steel for a truck tool box?
Aluminum for the best balance of weight and corrosion resistance — the right call in a salt state or if you're watching payload. Steel for maximum impact and pry resistance at a lower price, if the box is going to take abuse.

What size truck tool box do I need?
It depends on the type. For a crossover, measure across your bed rails, outside edge to outside edge — full-size trucks typically take 69–72 inches, mid-size 54–63. For a topside, measure the length of the bed rail front to back. For an underbody box, measure the clear frame rail. For a chest, measure between the wheel wells.

Do I need to measure between the wheel wells?
For a chest, yes — it's the governing number, since the box sits on the floor between them. For a crossover, only on a short bed or with a deep tub, where the tub can hang far enough down to foul them. For a topside or underbody box, no.

What's the difference between tool box length and width?
On a crossover, length is the measurement across your bed, rail to rail, and width is front to back. A 72-inch box is 72 inches across your bed.

Drop-down door or barn doors on an underbody box?
Barn doors on anything 60 inches or longer. A drop-down that size means bending over a five-foot panel to reach the back, and it swings into whatever's parked beside you. Below about 48 inches a drop-down is fine, and the open door doubles as a small work shelf.

What tool box goes on a flatbed or dually?
Topside boxes, usually in matched driver- and passenger-side pairs, plus an underbody box on the frame. Flatbeds have no conventional bed wall, so crossovers don't apply.

How long does it take to install a truck tool box?
A crossover or topside box on J-bolts is usually under an hour with a helper. A chest often needs no mounting at all. An underbody box is two to four hours for your first one, and needs jack stands, a drill and separate brackets.

Are truck tool boxes worth it?
For anyone carrying tools daily, yes. The return comes from tools that last longer, time not spent loading and unloading every night, and the theft you avoid.

Still weighing it up? Tell us your truck, your bed length and what you haul, and we'll tell you which style fits — and which one we'd put on our own truck.

→ Shop truck tool boxes

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