Bed height vs garage: the most regretted number in a van build
· 7 min read
Ask a hundred builders what they would change about their van and the same answer keeps coming back: the bed height. Not the electrics, not the layout — the one number that got fixed the day the frame went in and can never be nudged afterwards. It is the most regretted dimension in van conversion because it is the only one that has to satisfy two demands at once, and those demands pull in opposite directions inside an interior height you cannot change.
Raise the platform and the garage under it grows — bikes stand up, boxes stack, the toilet slides out. Lower it and you can sit up in bed with a coffee and a laptop instead of propping yourself on an elbow. Between those two positions sits every real van, and in a lot of vans one of them simply has to lose.
The arithmetic, stated once
Two lines of maths govern the whole decision. Learn them and the forum arguments stop being opinions.
Room to sit up = interior height − (platform height + mattress thickness). What you need there is your own sitting height — bum to crown, measured sitting on a hard floor with your back straight, which is about 850 mm for an average adult — plus roughly 25 mm so your hair is not brushing the ceiling. Call it 875 mm over the mattress. Measure yourself; this is the one number in the whole build that is genuinely personal, and tall people who use the average lose 60–80 mm they never had to lose.
Garage clearance = platform height − about 70 mm. This is the part people forget, and it is the part that ruins the plan. Your gear does not slide under the mattress; it slides under the structure — the frame rails and the slats or ply deck on top of them. A conventional 30 × 70 mm timber frame with a 12 mm deck eats about 70 mm off the top of the garage. Design a 900 mm platform for a 900 mm bike and you have built an 830 mm garage.
What actually has to fit underneath
These are the clear heights real loads need — floor to the underside of your bed frame. They are the same figures the VanPlot calculator runs on. Measure your own bike anyway; drop bars and riser bars vary more than any table admits.
| Load | Clear height needed | Platform height that gives it |
|---|---|---|
| Boxes and loose gear | 400 mm | 470 mm |
| Road bike, front wheel off | 850 mm | 920 mm |
| MTB, front wheel off, dropper post down | 900 mm | 970 mm |
| Mountain bike, front wheel off | 950 mm | 1020 mm |
| Bike upright, both wheels on | 1100 mm | 1170 mm |
| Motorbike | 1100 mm | 1170 mm |
The right-hand column is the load plus that 70 mm of structure. It is also, quietly, the list of vans you have just ruled out. For the full picture of what else lives down there — wheel-arch intrusion, lashing points, board diagonals, side versus rear loading — see the garage dimensions guide. This post is only about the collision between that space and your head.
Where the 36–39 inch consensus comes from
Sprinter-Source has polled bed height more times than anyone has counted, and the answers cluster in the same place every time: a platform somewhere between 36 and 39 inches — roughly 915 to 990 mm. That is not folklore. It is the narrow band where a mountain bike with its front wheel off and its saddle dropped will stand underneath, and a person of ordinary height can still get upright in bed, in a high-roof van.
Note the last clause. The consensus was formed by people in tall vans. Run the same platform through a shorter roof and it stops working, which is why the poll answer keeps disappointing the people who copy it.
What each platform height actually buys
Interior height 1.9 m (a standard H2 roof, finished floor and ceiling already accounted for), mattress 120 mm. Sitting need is 875 mm over the mattress; below about 700 mm you cannot meaningfully sit up at all.
| Platform | Clear garage | Over the mattress | Verdict |
|---|---|---|---|
| 470 mm | 400 mm | 1310 mm | Kneel, sit, work in bed. Boxes and drawers only |
| 700 mm | 630 mm | 1080 mm | Fully upright with room over your head |
| 850 mm | 780 mm | 930 mm | Still sit up comfortably. No bike stands here |
| 905 mm | 835 mm | 875 mm | Exactly the sitting limit — the ceiling of what this roof allows |
| 970 mm | 900 mm | 810 mm | MTB with dropper down fits. You sit with a bowed head |
| 1020 mm | 950 mm | 760 mm | Full MTB fits. Elbow-prop territory |
| 1170 mm | 1100 mm | 610 mm | Upright bike or motorbike. You cannot sit up, ever |
The bad news, said plainly
Look at that table again. In a 1.9 m interior with a 120 mm mattress, the highest platform that still lets an average adult sit up is 905 mm. The lowest platform that clears a road bike with its front wheel already off is 920 mm. The two requirements cross — by 15 mm, which is nothing, and which is also everything, because there is no way to negotiate with it.
So: some vans cannot do both. A standard H2 roof will not give you a sit-up-in-bed fixed bed and a bike garage under it. Not with clever joinery, not with a thinner frame, not by being optimistic about your posture. The honest options are a taller roof, a thinner mattress, taking the front wheel off (or off and the bike laid down), or the bikes going on a rear rack and the garage carrying boxes instead.
Move one input and the maths unlocks. The same van with an 80 mm mattress allows a 945 mm platform — an 875 mm garage, which clears the road bike with 25 mm spare. A high roof at 2.05 m interior allows a 1055 mm platform and a 985 mm garage, which swallows a full mountain bike with the front wheel off. That single roof decision is worth more to this problem than every other choice in the build combined, and it has to be made before you buy the van.
Ways to buy height
Take the front wheel off. An upright bike wants 1100 mm; the same bike on a fork mount wants 950 mm. That is 150 mm for the price of a fork mount and ten seconds at each end of a ride — the cheapest height you will ever find in a van, and it stops the bike falling over as a bonus.
Drop the saddle. A dropper post gives 100 mm or more of travel — about four inches, and riders who have one forget they can use it for parking. In practice it buys about 50 mm of garage, because once the saddle is down the handlebars become the tallest point and set the number. Worth having; not worth planning the whole bed around unless you have measured that your saddle really is the high point.
Make the bed move. A hinged or lifting bed section gets you a low sleeping surface most nights and a tall opening when the bike goes in — see the Murphy bed layout for the version that folds against the wall entirely, and the fixed versus convertible comparison for what you trade away in daily faff.
Change the roof. A high roof or a pop-top ends the argument. A pop-top adds sitting height only where the roof opens, so it solves the bed problem specifically — check it opens over the bed, not over the kitchen.
The rule that survives contact with reality
Sit as low as the load allows. Take your tallest garage item, add 70 mm for the structure, and build the platform at exactly that height — not a comfortable round number above it. Every millimetre of platform above the load is empty air under a bed you will never look at, paid for out of the space over your face. Headroom on the mattress is spent every single night, twice a day, for the life of the van. Dead space in the garage is spent never.
The people who regret their bed are almost always the ones who rounded up “for a bit of margin” and then spent five years crawling into a slot.
Two details that bite after the build
A transverse bed needs a stop board. Sleeping across the van means braking pushes the mattress lengthwise along the platform, and a foam mattress on a smooth ply deck will creep forward — a little each stop, until it is hanging over the front edge and your sheets are a mess every trip. A 40–50 mm lip along the front edge of the platform, or a batten screwed to the deck, fixes it permanently. Nobody thinks of it during the build; the forums are full of people retrofitting one.
Decking spans matter more than deck thickness. Thin ply over widely spaced supports sags, and it sags under load in the middle, exactly where you sleep — a deck that felt solid when you knelt on the edge can bow 15 mm under two people. Keep supports on 250–300 mm centres and 12 mm ply or 18 mm slats will stay flat for good. Adding a support is minutes of work now and a full dismantle later.
See the squeeze before you cut plywood
This is a problem you solve with a tape measure and two subtractions — but only if you know your van's real interior height at the bed, which is not the brochure figure, because the roof curves and the bed usually sits under the curved part. VanPlot knows the actual internal geometry of your specific vehicle variant, roof shape included, and it knows where you have placed the bed, so it can tell you what is left over the mattress and what is left under the frame at the same time. The squeeze shows up as a number while it is still free to fix. If you just want the arithmetic, the bed height calculator is free and takes thirty seconds: put in your roof, your mattress and your bike, and it will tell you whether your van can do both — or which one has to lose.