An RV leveling app for iPhone: where the phone goes and how to trust the reading

What the app needs from the phone

It reads the gravity direction from the built-in motion sensor, around 30 times a second. No network is involved and the app never asks for your location. If a device has no motion sensor the Level tab says No motion sensor and the other tabs still work.

Where does the phone go?

Flat, screen up, on something that moves with the vehicle: the floor, a step or the dashboard. The app measures how far the phone is from horizontal, and past 45° it stops printing numbers and asks you to Lay the phone flat. Held upright in a hand it would measure your hand.

Point the top of the phone toward the front of the vehicle. The app counts the top edge of the screen as the front and the right edge as the right side. On an iPhone the app stays in portrait, so a phone laid crosswise would swap the sideways and nose readings.

Set it up once per vehicle

1. Open Vehicle. A first install already has one profile; tap it to rename it and fill Dimensions and Weight from your papers.
2. Park on ground you trust to be level, put the phone in its usual spot and open Level.
3. Tap Zero. The phone's current reading becomes the zero for that vehicle, so a phone that sits 1° crooked stops lying to you.
4. Add other vehicles with Add vehicle and pick the active one with the circle on the left, then Zero each one separately.

Zero is a button, not an automatic step. If you never press it, the app reads the phone's own tilt as the vehicle's.

Settings worth a look

• Night mode (red) turns the screen black with a red tint, so you read it at the pitch without wrecking your night eyes. There is also a moon button on the Level tab.
• Vibration when level is on by default and gives one haptic tap when the level has held for 1.2 seconds. It makes no sound.
• Voice guidance while leveling is off by default. Switch it on if a partner is jacking while you watch: it speaks the wheel and the whole centimetres, such as front left up 7 centimeters, and says Level at the end.

How is it different from a bubble on the wall?

A stick-on bubble shows you are off. This one also converts that into lift: the screen lists four numbers in cm, the largest highlighted. With the default 3.5 m by 1.8 m vehicle, a 3.0° sideways tilt means 9.4 cm under each right-hand wheel and 0.0 under the left.

What it does not do: it does not run levelling jacks, it has no inch mode and it is not a certified instrument.

Phone on a car dashboard or a step?

Either works as long as the phone lies flat and does not slide. A curved dashboard can leave the phone resting at an angle; Zero removes that angle for that spot, but not if you move the phone to another place.

Each vehicle keeps its own Zero, so a caravan and a car can sit on different phone spots without clashing. After you change vehicles, check that the circle on the left is on the one you are in.

Questions and answers

More RV Level guides

• How to level an RV with blocks, and how high each one has to be
• How to level a caravan on a slope: side to side first, then front to back
• RV payload calculator: how many kilos you can still put on board
• RV axle weight: compare what you weighed with what the plate allows
• Caravan nose weight and tongue weight: compare it with the hitch limit
• All questions about RV Level
• Back to RV Level