Height of Motorhome

12' 1 1/4" according to FMC Magazine.

Two inchs higher than the bridge..

No, one one can. Modifications could have been made the original numbers might have been incorrect (intentionally) for any number of CYA reasons.
The coach is certainly going to be 13'-6" or lower as that is the National height limit (regionally this might vary to as high a 14'-6").
Even a coach which lists a 11'-7" height (that's my coach) has antennas that scrap the 13' bridges we pass under. We have also added satellite TV antennas to the roof which exceed the manufacturers height expectations. If you are concerned about the coach height you are going to have to do (or have done) some real world measurements to ensure you are not surprised. The salesman is going to lie to you (even if it didn't matter) as they have no idea about any of the questions you have asked. If you want to know something, YOU AND ONLY YOU, need to find the answer.
Sorry, I used to be a car salesman.

If buying at a dealer, have him pull it in through his 14' door while you are on a ladder. Find the tallest point and measure to the top of the door.

Get on the roof and run a tape measure to the ground and eye ball it. I did

You can get close to the correct actual measurement with some of the previous suggestions. Here is a method to be sure:
1-Park the MoHo and make it level.
2-Place a long 2x4 across the roof on top of the highest point.
3-Use a level to make sure it is correct at both sides.
4-Measure from the Underside of the 2x4 to the ground.
That is your actual - you may wish to add something for 'clearance'.
Bend-able antenna are not usually included - but a TV antenna in the 'up' position when going under a low bridge can ruin your day and cost big $$$ if you damage the roof as it is pulled over.
JMHO!

I would say 12' 11"

Well, I think it's too important a piece of information to leave to others. I climbed on the roof, found the highest point (antennae, AC's, and such) and ran a tape measure to the ground. Then I added a few inches for safety. I then printed that measurement out with a label maker and stuck it on the inside of the drivers windshield so I'd never forget.

ccxnola wrote:
You can get close to the correct actual measurement with some of the previous suggestions. Here is a method to be sure:
1-Park the MoHo and make it level.
2-Place a long 2x4 across the roof on top of the highest point.
3-Use a level to make sure it is correct at both sides.
4-Measure from the Underside of the 2x4 to the ground.
That is your actual - you may wish to add something for 'clearance'.
Bend-able antenna are not usually included - but a TV antenna in the 'up' position when going under a low bridge can ruin your day and cost big $$$ if you damage the roof as it is pulled over.
JMHO!

That's the correct method that I used.

I then taped a paper with the height on the top left inside corner of my windshield. I gave my self a two inch buffer just for the heck of it.

ccxnola wrote:
You can get close to the correct actual measurement with some of the previous suggestions. Here is a method to be sure:
1-Park the MoHo and make it level.
2-Place a long 2x4 across the roof on top of the highest point.
3-Use a level to make sure it is correct at both sides.
4-Measure from the Underside of the 2x4 to the ground.
That is your actual - you may wish to add something for 'clearance'.
Bend-able antenna are not usually included - but a TV antenna in the 'up' position when going under a low bridge can ruin your day and cost big $$$ if you damage the roof as it is pulled over.
JMHO!

That's the correct method that I used.

I then taped a paper with the height on the top left inside corner of my windshield. I gave my self a two inch buffer just for the heck of it.