RV Leveling Block Calculator: How Many Blocks Do I Need?

How far the tire has to come up is the distance between your tires multiplied by the tangent of the tilt — about 2.8 in for 2° on an 80 in track. The block count is the part everyone gets wrong: a three-inch ramp is six blocks, and a tandem axle needs two of them.

A tilt is not a lift

A level on the floor reads an angle. Blocks are sold in inches. The step between them is the width of your own rig:

lift at the tire = distance between the tires × tan(tilt)

The trailer pivots about the tires on the high side, so the far side has to travel the width of the rig’s stance. On an 80 in track, 1° is 1.40 in and 2° is 2.79 in. On a narrow trailer the same 2° is less; measure from the same edge of one tire to the same edge of the other and use your own figure, which is why the calculator prints what the answer would be 8 in either side of it.

If you have no angle to type in, use the other mode: rest a level across the floor side to side, lift its low end until the bubble centers, and measure the gap underneath. The gap over the length of the level is the same slope the tires sit on.

Why a three-inch ramp is six blocks

Blocks do not stack straight up — you have to drive onto them, so each layer needs the layers below it to reach back down to the ground. Tri-Lynx’s own figure: “One Lynx block is going to raise your RV by one inch, but for a two-inch raise you’re going to have to build a pyramid with three blocks.”

Carry that on and the count grows faster than the height:

Lift	Blocks per tire	Tandem axle (two tires)
1 in	1	2
2 in	3	6
3 in	6	12
4 in	10	20
5 in	15	30

A ten-pack covers a single-axle trailer to four inches, or a tandem to two. The forum answer — “get ten and see” — is right until the site tips 3°.

How level is level enough

There is a published number, and it is not where most people assume. Norcold’s owner’s manual for its N61X and N81X refrigerators states the fridge “is made to operate within 3° off level side-to-side and 6° off level front-to-back (as looking at the front of the refrigerator)”.

Two things follow. The first is that 3° is a lot of lift: on an 80 in track it is 4.2 in at the tire, more than a 4 in leveler covers. The second is the part in brackets — the limits are measured at the fridge, not at the rig. A fridge on a side wall faces across the trailer, so your side-to-side tilt is its front-to-back, and the looser 6° applies. Turn the same fridge to face the front of the rig and the tighter 3° does.

Dometic’s RM1350 manual puts the same requirement in words rather than degrees: the vehicle “needs to be leveled enough to be comfortable to live in (no noticeable sloping of floor or walls)”. Both makers also say the same thing about driving: Norcold’s is that “while the refrigerator should be level when the vehicle is stopped, performance during travel is not usually effected”.

Blocks or a leveler that stops anywhere

Blocks land on whole inches. If the calculator says 2.8 in, three blocks overshoot by about 0.2 in — which on an 80 in track is 0.15°, nowhere near any limit above. Rounding is not the reason to buy something else.

The reason is the two ends of the range. A curved leveler stops wherever you stop the trailer: Andersen’s is “precise leveling at any increment between 1/2” and 4"", one per tire, and it comes with the chock that holds it. Blocks go higher — five of Tri-Lynx’s — and they are also what makers describe going “under stabilizers, jacks, tongue supports”, so the same pack does more than one job.

What each maker will say out loud

The stack limit is the figure that decides whether a tall ramp is a ramp or a stunt, and only some makers publish one:

• Tri-Lynx: “For leveling in a pyramid, we do not recommend any higher than 5.5 inches (5 levelers)” — and 8 levelers for stabilizing, where nothing drives onto them. Capacity 40,000 lb.
• Andersen: no stacking at all; 4 in is the top of the leveler’s range, 30,000 lb, tires to 32 in.
• Ultra-Fab: an inch a block and 30,000 lb, but no maximum stack anywhere on its pages. That is why the calculator offers its blocks only where no stacking is involved — an unstated limit is not a high one.

The blocks compared

Model	Lift	Stack limit	In the pack	Capacity	Buy
Lynx Levelers 10 pack	1 in per block, stacked	5 levelers (5.5 in) for leveling, 8 (8.5 in) for stabilizing	10 blocks with a nylon storage bag	"Lynx Levelers can withstand up to 40,000 lbs"	Check price(opens in a new tab)
Ultra-Fab leveling blocks	1 in per block, stacked	Not published by Ultra-Fab	10 blocks	"up to 30,000lbs without shifting"	Check price(opens in a new tab)
Andersen Camper Leveler	Any height from 1/2 in to 4 in, no stacking	Not stacked — 4 in is the top of its range	One curved leveler with one Tuff Chock	"Works great on trailers up to 30,000 lbs"	Check price(opens in a new tab)

Where this goes wrong

1. Reading the tilt and buying by the degree. Degrees only become inches once you measure the track width.
2. Counting one block per inch. Three inches is six blocks per tire.
3. Blocking one tire of a tandem. Both come up, or neither does.
4. Stacking past the maker’s figure. Tri-Lynx stops at five for leveling; Ultra-Fab never says, so there is nothing to stay inside of.
5. Leveling side to side after unhitching. Do it hitched, so the tongue jack is not holding the rig up while a wheel climbs.
6. Forgetting the weight it all sits on. A tandem trailer puts thousands of pounds on two ramps — our cargo capacity calculator works out what your loaded trailer actually weighs.
7. Blocking one tire of a dual pair. Michelin’s motorhome tire guide says a block should be wider than the tread and longer than the tire’s footprint, and that on duals the weight should sit evenly on blocks under both tires — otherwise “the sidewall cables can become fatigued and damaged, resulting in a sidewall rupture”. The same guide sets motorhome tire pressure from scale weights, which our tire pressure calculator works out.
8. Levelling to fix a bed you cannot sleep in. Side-to-side tilt is worth correcting; a mattress that never fitted the platform is a different problem, and the mattress size finder sorts that one out from a tape measure.

Questions worth answering