ALTIM–O–TRON

The altimeter that works where the internet doesn't

No cell service. No Wi-Fi. No problem.

Altim-O-Tron's altimeter screen: a glowing circular dial reading 7,347 feet, with GPS signal, coordinates, vertical speed, air pressure, and an elevation profile.
Core instrument

Precision Anywhere

GPS gives you absolute altitude. The barometer gives you instant response. Altim-O-Tron fuses both into one smooth, honest readout — satellites for the truth, air pressure for the reflexes.

The result updates the moment you step up a ledge, and still knows exactly where sea level is an hour later. Every calculation happens on the phone in your hand, using sensors that were already there.

GPS satellites don't care if you're off the grid.

ALTITUDE 0 FT ± 10 FT
Instrument panel

Six Instruments, One Screen

Everything below runs on sensors your iPhone already has, with no account, no signal, and no permission to phone home.

GPS + Barometer Fusion

Satellite altitude for accuracy, air pressure for instant response. One readout you can trust on a ridge line.

Altitude Intel

300+ landmarks, animals, and disasters at every elevation. You are currently level with something. We'll tell you what.

Measure Your Way

Feet and meters, obviously. Also fathoms, furlongs, smoots, and giraffes. Choose wisely.

True Compass

A proper rose with true north computed on-device, plus course and ground speed in units of questionable judgement.

Record Every Climb

Captures your elevation profile with the screen locked and the phone in your pocket. Export any session as GPX.

Read the Sky

An offline barograph logging sea-level-corrected pressure and its three-hour tendency — the oldest forecast there is.

Altitude Intel

You Are Level With Something

A database of 300+ things at every altitude, from the wreck of the Titanic to the stratosphere. It updates as you climb.

Current Altitude 0 FT

You're at the same altitude as

Mexico City

300+ entries · entirely offline · no lookups

Units

Measure Things
Your Way

Six ways to express exactly how far above the sea you are. Two of them are sensible.

  • Feet
  • Meters
  • Fathoms
  • Furlongs
  • Smoots
  • Giraffes

Displays altitude in giraffes.
For science.

Navigation

True North,
Computed On Board

Magnetic north is where the needle points. True north is where the map thinks you're going. Altim-O-Tron computes the declination between them on-device and shows you both, alongside your course and ground speed.

True HDG 247° Geographic
Mag HDG 233° Magnetic
Accuracy ± 4° Heading

Yes, speed can be displayed in furlongs per fortnight.

HEADING 247° WSW TRUE NORTH
Session recorder

Record Every Climb

Start a session at the trailhead and put the phone away. Altim-O-Tron keeps recording your elevation profile with the screen locked, then hands you total ascent, total descent, and the whole shape of the day.

Export any session as a standard GPX track — geotagged and ready for whichever mapping app you already trust.

Total Ascent 0 FT
Total Descent 0 FT
Max Altitude 0 FT

Works beautifully in airplane mode.
Mostly because airplanes are high.

06:12 14:48 ELEVATION PROFILE
The app's session recorder screen with a Start Recording button.
Barograph

Read the Sky

The barograph logs air pressure for 48 hours and corrects it to sea level using your altitude — so climbing a hill doesn't read as an incoming storm.

Then it reads the three-hour tendency: steady, rising, or falling. Falling fast is the sky's way of suggesting you head down.

Sea-level 1,012.6 HPA
Tendency STEADY 3 Hour
Samples 0 Logged · 48H

Sailors relied on this for centuries.
They probably would have appreciated an iPhone.

LO 1,012.5 SEA-LEVEL HPA HI 1,018.1
The app's weather screen showing a steady pressure tendency and a 48-hour barograph.

No Masters

  • No Accounts
  • No Ads
  • No Tracking
  • No Analytics
  • No Cloud
  • No Networking
  • Nothing leaves your phone.

No networking code.
We literally can't spy on you.

Read the full privacy policy

The Altim-O-Tron app icon.

Download Altim–O–Tron

For iPhone. Requires a device with a barometer — which is every iPhone since the 6.

Altim-O-Tron's compass screen, showing a heading of 247 degrees with true and magnetic readouts.