RV fit calculator

Type your rig, type a driveway length, and see the two drawn to the same scale. Every rule and every assumption is on this page and you can change each one.

1. Your rig

Configuration Tow vehicle length (ft) Trailer overall length, tongue included (ft) Hitch gap, bumper to coupler (ft)

2. Width and slide-outs

Body width (ft) Slide-outs, driver side Slide-outs, passenger side Slide depth (ft)

3. The site

Driveway length (ft), from the site page Safety margin (ft), our assumption Tow vehicle parks off the driveway (unhitched)

On Recreation.gov the number you want is Driveway Length on the campsite page; when it reads 0 the site has not been measured and Max Vehicle Length is the only limit published. How those two numbers differ.

Does not fitA 40 ft driveway is 8 ft shorter than the 48 ft rig.

tow vehicletrailer or motorhome body, slide-outs in lighter inkfitstightdoes not fit, overflow hatched

Combined length

48 ft

Required driveway (rig + margin)

53 ft

Width with slides out

8.5 ft

Spare driveway

-8 ft

The rule, stated

Fits: the driveway is at least the combined length plus the margin.
Tight: the driveway is at least the combined length but shorter than combined length plus margin.
Does not fit: the driveway is shorter than the combined length.

Combined length is arithmetic on what you typed: tow vehicle + hitch gap + trailer. The margin is ours: 5 ft by default, so the tow vehicle's nose is not on the loop road and the rear door can open. It comes from no source and you can set it to zero. "Tight" is the band between the bare rig and rig plus margin.

Assumptions you can change

Input	Default	Why that default
Hitch gap (travel trailer)	3 ft	Rear bumper to the coupler on the ball. Depends on your receiver and tongue; measure yours hitched.
Fifth-wheel overlap	4 ft	The length of trailer that sits over the truck bed and is subtracted from truck plus trailer. Depends on where the pin sits in the bed.
Tow-bar gap (motorhome + car)	3 ft	Rear bumper to the towed car's front bumper with the tow bar extended.
Body width	8.5 ft	A common RV body width before mirrors and slides. Replace with your spec sheet.
Slide depth	3 ft	Typical extension of one slide-out. Replace with yours.
Safety margin	5 ft	Editorial. Room to open the rear door and keep the tow vehicle's nose off the campground road.

Width is reported but not judged: almost no official page publishes site width, so the calculator shows your width with slides out and leaves the comparison to you. Yosemite, for example, publishes only a maximum RV length and maximum trailer length per campground (Upper Pines: 35 ft and 24 ft).

What this calculator does not know

Whether the site is back-in or pull-through, or how sharp the approach is. A 40 ft driveway on a tight loop can be harder than a 35 ft pull-through.
Whether the campground's maximum applies to the trailer alone or to the whole rig. Yosemite lists "RV length / trailer length"; Fishing Bridge RV Park lists combined length. Each campground page quotes the exact wording.
Availability. Nothing on this site is a reservation or a claim that a site is open.