Your best bet to get an accurate measurement is to not place the tape measurer on the bottom part floor but simply run it straight down the length.
How to measure your truck bed for a tool box.
For crossover toolboxes be sure to properly measure the distance from the outside of one rail to the outside of the other.
And measure the distance from the top to the bottom of the bed.
Measure the outside distance between your bed rails and compare it to measurement a on the illustration above.
Again the tape measure should be in a straight taut line even with the top of the bed.
This measurement will let you know the maximum height of your toolbox.
Using the picture of the low side box above and the instructions below measure your truck bed to insure proper fit.
For this number measure how tall your truck bed is from the floor to the top of the rail.
Record this measurement and label that number width.
It s key to properly measure your truck bed for a toolbox.
How to measure your truck bed for a crossover tool box using the picture of the crossover box above and the instructions below measure your truck bed to ensure proper fit.
Just make sure to keep it even and not move it away from the bulkhead.
Moving along your bed rail extend the measuring tape to the inside edge of the top of your tailgate.
Now you have the measurements of your truck bed.
If you are going to buy the accessory like toolbox or tonneau cover truck caps then change the dimensions accordingly like in the metric system in feet or inches.
Most standard boxes won t extend all the way to the floor but some oversized tool chests might be taller than your bed and won t fit properly.
First measure the height of the rails and the distance between the rails.
Hold one end of your tape measure against the inside of your truck bed s left front corner and have someone pull the tape measure until it reaches the inside of the front right corner.
Measure the inside length of your bed from inside the front bulkhead rail to the inside of your tailgate compare that measurement with dimension a in the illustration.