RV Leveling Block Calculator

1. Park in the spot you actually want, engine off, parking brake on (and transmission in Park or in gear).
2. Stick a couple of cheap bar/bubble levels on a flat rear-facing surface and a flat side surface — or just hold a phone level app in place. Drag the matching bubble above to the same spot; it floats toward the HIGH side, so the low side is the opposite.
3. Lay the block stacks just ahead of the low tires, drive up slowly, chock a wheel.
4. Re-check the levels. Suspension squish and stack nesting mean one refinement round is normal.

Carry enough to build a 3-block stack under two tires on the same side — that's six blocks in use at once, which handles the worst site you should still be parking on. A standard 10-pack covers that with spares left over for odd situations like a stack under a third tire or a pad for your tongue jack. If you camp mostly in developed campgrounds with graded pads, you'll rarely use more than two or three at a time, but the extra weight of a full pack is small and the day you need it you'll be glad it's aboard.

Yes, within the limits the manufacturer publishes — check the weight rating on your specific blocks, because it applies per stack, not per pack. Interlocking blocks are designed to nest into each other and stay put; flat pads and random boards are not, so don't mix types in one stack. Keep each stack pyramid-shaped where you can, with a wider base than top, and make sure the whole tire contact patch is supported. Once a stack goes past four blocks it gets noticeably less stable and the drive-up gets steep — at that point the right fix is a flatter site or turning the rig around, not a taller tower.

Side-to-side first, with blocks under the low-side tires — that's the axis you can only fix by raising wheels. For a trailer, once you're level side-to-side you chock the wheels, unhitch, and handle front-to-back with the tongue jack, which is far easier than blocking. For a motorhome or camper van, this calculator handles both axes at once: it tells you the block count for every tire so a single slow drive-up fixes roll and pitch together. Either way, re-check your levels after the rig settles — one refinement pass is normal.

Most RV refrigerators are absorption fridges: instead of a compressor, they circulate an ammonia solution through tubing by heat and gravity. When the rig sits off-level, that solution pools in low spots of the tubing, circulation stalls, and the boiler can overheat — run it that way long enough and you can permanently damage the cooling unit. The usual tolerance is roughly 3° side-to-side and 6° front-to-back, so a rig that feels only slightly tilted can still be outside spec. If you have a 12V or residential compressor fridge, relax — it doesn't care about level, though your sleep and your frying pan still do.

Yes — dimensional lumber is the original leveling block, and plenty of RVers still carry it. Use pressure-treated 2x8 or 2x10 cut into lengths wide enough that the full tire contact patch sits on wood, with nothing hanging off the edges. Stagger stacked boards like bricks so they can't slide, and step stack lengths so the tire has a ramp up rather than a cliff. The trade-offs are weight, bulk, and lifespan: untreated wood rots, and even treated boards split over time, so inspect them each season and retire anything cracked.

Always. Blocks raise the rig; they do nothing to stop it rolling, and a leveled site still has slope you've merely compensated for. Chock the downhill side of at least one wheel that's on the ground — before you unhitch a trailer, and before you walk away from a motorhome, even with the parking brake set. Chocks are cheap insurance against one of the genuinely dangerous RV failure modes, so treat them as part of the leveling routine, not an optional extra.