Two very different machines answer this. A container mast forklift is an ordinary counterbalance truck fitted with a low, full free lift mast that clears the door of a standard box, roughly 7 ft of headroom, and can lift inside without hitting the roof. A container handler is the yard machine that stacks loaded boxes, and it is a weekly hire of a different order entirely.
Lowered height is the number to give the branch
The specification that decides whether a truck can drive into a box is its overall lowered height with the mast down. A standard warehouse truck stands well above the door opening and will not enter. Give the branch the internal door dimensions of the container and let them match a mast, rather than asking for a capacity and hoping.
Full free lift, or the mast grows as you lift
On a normal mast the inner section rises above the truck as soon as the forks do, which is useless under a container roof. A full free lift mast raises the forks a good way up the first stage without the mast extending. That is the feature that lets a truck stack two high inside the box instead of only sliding pallets along the floor.
Capacity falls as the load moves forward
A truck rated at 5,000 lb is rated at a stated load centre, and a deep pallet or an awkward crate moves the weight forward and drops the real capacity. Ask for the load chart, and give the branch the pallet depth as well as the weight. Federal rules on powered industrial trucks require the truck to be marked with those ratings.
Getting the truck to the container door
Everything above assumes the machine can reach the opening squarely. A ground level box on gravel needs a ramp and firm approach; a dock height container needs a plate and a level transition. Cushion tires want smooth concrete and pneumatic tires want a yard, so say what the surface is when you book.
Questions people ask about container forklift rental
Will a standard forklift fit inside a shipping container?
Usually not, because the mast is taller than the door opening. What you need is a container mast, sometimes listed as a low mast or full free lift truck, and every general rental branch that serves warehousing will know the term. Confirm the lowered height in inches rather than relying on the description.
What capacity do I need to unload a container?
For palletised freight a 4,000 to 5,000 lb truck covers most work, so long as the load centre matches. Machinery, stone or drummed goods can run far higher, and at that point the practical answer is often unloading from outside with a bigger truck and longer forks.
Is a container handler the same hire?
No. Handlers that stack loaded or empty containers are heavy specialist machines, quoted by the week with transport arranged separately, and often supplied operated. They belong to port and depot work rather than unloading a single delivery, which a container mast truck does far more cheaply.