Truck Tool Box Full Size Guide

A truck tool box full size is a crossover box that mounts across the bed behind the cab of a full-size pickup, wide enough to span the bed rails. It sits behind the cab and leaves the rest of the bed open for cargo. This guide explains what counts as full size, the lengths and depths the listings show, and how to measure the bed before ordering.

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Below: what full size means, the lengths and depths in the listings, how to measure the bed rails, and what to check on locks, lids and seals.

Truck tool box full size: what full size means

Full size describes the truck, not a single box size. A full-size truck has a wider bed than a midsize truck, so a box built for it spans a wider rail-to-rail gap. The DECKED Tool Box listing fits almost every full size truck manufactured from 2001 to the present, and lists a bed rail gap of 61.375 inches to 70.5 inches. Boxes in the listings run 63 inches to 72 inches long, so the length to match is the gap between the bed rails on the truck, not a number on the box alone.

Full-size box lengths and depths in the listings

Depth runs 12 inches on the narrow Dee Zee to 25.5 inches on the DECKED box, with the COOLBAG, Aikosin and Weather Guard 121-5-04 boxes at 20 inches deep. Heights run 13 inches on the Aikosin to 18.5 inches on the Weather Guard 123-5-03. A taller box sits higher behind the cab, so check the height against the view out of the rear window.

Capacity is stated for two listings: the 70-inch COOLBAG at 10.6 cu. ft. and the Weather Guard 121-5-04 at 11.0 cu. ft. The 63-inch COOLBAG listing repeats the same 10.6 cu. ft. figure, so do not rely on it for that box. For the other boxes, the listings state dimensions and not capacity.

The UWS listings need a careful read. The EC10603 title calls it a 72-inch box while the spec table lists 77.0 inches as the longest dimension, and the EC10552 title calls it a 69-inch box with the same 77.0 inch figure in its spec table. Trust the title size for the box and check the listing again before ordering. The 63-inch COOLBAG listing also disagrees with itself on height: the title and the spec table say 15 inches while the bullets say 16 inches.

How to measure the bed before ordering

The size lives in the bed rails, not in the box title. Work through the checks in order.

1. Measure the rail-to-rail gap. Measure the gap between the inside faces of the bed rails, behind the cab. The DECKED listing fits a gap of 61.375 inches to 70.5 inches, so compare the measurement with the range the listing states.
2. Check the depth the bed allows. The COOLBAG, Aikosin and Weather Guard 121-5-04 boxes are 20 inches deep, and the narrow Dee Zee is 12 inches deep, so check the depth against the bed before ordering, not after.
3. Check the lid swing. The Weather Guard boxes open at 90 degrees, and a low-profile lid keeps the view out of the rear window clearer. Make sure nothing behind the cab gets in the way of the lid.
4. Check the fitment notes. The DECKED box does not fit Rambox, Stepside trucks, Service Bodies, GMC Carbon Pro Bed, Chevy Silverado EV, Ford F-150 Heritage Edition, and Nissan Titans, and Tacoma Tundra models from 2022 onward need the Tundra bedrail-specific SKUs.
5. Check the mounting. UWS crossover boxes come with pre-drilled mounting slots and hardware, and the COOLBAG boxes mount across the bed behind the cab.

Locks, lids and seals: what to check

A lock keeps the box shut, and the listings show several kinds. The COOLBAG and Aikosin boxes come with a lock and keys, the Weather Guard boxes use a tamper-resistant push button lock, the 121-5-04 uses the 1KEY ULTRALOCK, which lets one key work across boxes, and the Dee Zee uses lockable stainless steel paddle handle latches.

Lids matter as much as locks. The Aikosin box has dual lids with gull wings for half-box access, the UWS boxes use a RigidCore lid filled with solid foam, and the DECKED lid opens on a gas strut with a steel-reinforced lid and tamper-resistant locks. The Weather Guard boxes open at 90 degrees. A lid that binds can leave a gap at the seal, so check how the lid is built before ordering.

Weather protection comes from the seal and the lid. The Weather Guard boxes list a full weather seal, the DECKED box lists a seamless build with a H2Zero Gasket and drain holes, and the Aikosin box lists an over-lapping lid that keeps moisture out. Check what the listing says about the seal and the lid, not the title alone.

Most boxes in the listings are aluminum. The COOLBAG and Aikosin boxes are aluminum, the UWS tubs are welded 0.058-inch aluminum, the Dee Zee is .056 Brite-Tread aluminum, and the Weather Guard boxes are aluminum. The DECKED tub and lid are compression-molded resin instead, which the listing says will not crack or dent and will not fade in the sun. Weights are stated for a few boxes: the UWS EC10603 at 59.0 pounds, the UWS EC10552 at 36.0 pounds, the Weather Guard 121-5-04 at 76.5 pounds, and the Dee Zee at 30.0 pounds.

Common mistakes

• Ordering by the length on the box alone, without measuring the rail-to-rail gap.
• Trusting the spec table size when the title says something else, as with the UWS listings.
• Assuming every full-size truck takes the same box: the DECKED listing names trucks it does not fit, including Rambox and Stepside trucks.
• Treating the 10.6 cu. ft. figure as the capacity of the 63-inch COOLBAG, when the same figure appears on the 70-inch box listing too.
• Forgetting the lid: a box that opens at 90 degrees needs clearance behind the cab.

FAQ: garage tools

What size is a full size truck tool box?

There is no single size. Boxes in the listings run 63 inches to 72 inches long, with the COOLBAG, Aikosin and Weather Guard 121-5-04 boxes 20 inches deep and heights from 13 inches to 18.5 inches. Match the length to the gap between the bed rails, and check the depth and height against the bed.

How do I measure my truck bed for a tool box?

Measure the gap between the inside faces of the bed rails behind the cab, then the depth and height the bed allows. The DECKED listing fits a rail gap of 61.375 inches to 70.5 inches, so compare the measurement with the range the listing states before ordering.

Will a full size truck tool box fit a midsize truck?

Measure first. Full-size boxes are built for the wider rail gap of a full-size bed, so a midsize bed may be too narrow. Compare the rail gap with the range the listing states, such as 61.375 inches to 70.5 inches for the DECKED box.

Do full size truck tool boxes come with locks?

The listings name a lock or a lockable latch on most boxes here. The COOLBAG and Aikosin boxes come with a lock and keys, the Weather Guard boxes use a tamper-resistant push button lock, the DECKED box lists tamper-resistant locks, and the Dee Zee uses lockable stainless steel paddle handle latches. The UWS listings state stainless steel paddle handles and name no lock, so check the listing for the lock type, since a keyed lock and a push button lock open differently.

How much can a full size truck tool box hold?

Capacity is stated for two listings: the 70-inch COOLBAG at 10.6 cu. ft. and the Weather Guard 121-5-04 at 11.0 cu. ft. The 63-inch COOLBAG listing repeats the 10.6 cu. ft. figure, so do not rely on it for that box. For the other boxes, the listings state dimensions and not capacity, so judge by the length, depth and height.

Can I install a truck tool box myself?

The UWS listings say the boxes come with pre-drilled mounting slots and hardware for easy installation, and the COOLBAG boxes mount across the bed behind the cab. Follow the mounting instructions in the listing for the box.

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