E6B Slide Rule
Aviator circular slide rule
$2.99 · Designed for iPad. Not verified for macOS.
Do you love your Apple Watch but miss your circular slide rule from your aviator watch? Try this E6B designed for the Apple Watch.
This simple circular slide rule works the way your aviator watch does. For rate/time calculations it can be faster than a calculator: set the rate once and read every distance and time straight off the dial, without typing anything. If you're an aviator who would rather use a slide rule than a calculator, try this app. It is much easier than trying to punch numbers on a watch calculator. We created it for the watch, but it works on the iPhone and iPad, too.
Rotate the outer ring with your finger or with the Digital Crown. Let go mid-turn and it spins on and coasts to a stop. Slow down and the crown gets
finer under your finger, so you can settle exactly where you meant to. A click marks each numbered graduation passing the rate index — feedback only, never a
detente, so the dial will never nudge you onto a mark you did not choose.
THE FACE
Three concentric logarithmic scales, drawn to the proportions of the real thing.
• The outer scale carries rate, distance, fuel and quantity, and it is the ring that turns.
• The minutes scale sits inside it, fixed, with the rate index locked at twelve o'clock. The one pointer you read everything against never moves.
• The hours scale runs 1:00 to 10:00 beneath, so elapsed time reads directly without converting from minutes.
Complications on the watch face open it in one tap. Where you left the dial is where you find it, for a day.
On iPhone and iPad it's the same instrument, larger, with room for numerals the watch has to leave off.
WHAT IT DOESN'T DO:
There's no keypad and no equals key — you read the answer off the dial, the way the instrument is meant to be used. No network: the app has no reason to reach the internet and never does. Nothing is collected, nothing is tracked, and nothing leaves your device.
A reference and training tool. Not a certified flight computer — verify critical calculations independently.
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The developer, Western Chancellor LLC, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .
Data Not Collected
The developer does not collect any data from this app.
Accessibility
The developer has not yet indicated which accessibility features this app supports. Learn More
Information
- Seller
- Western Chancellor LLC
- Size
- 2.2 MB
- Category
- Utilities
- Compatibility
Requires iOS 17.0 or later.
- iPhone
Requires iOS 17.0 or later. - iPad
Requires iPadOS 17.0 or later. - Mac
Requires macOS 14.0 or later and a Mac with Apple M1 chip or later. - Apple Vision
Requires visionOS 1.0 or later. - Apple Watch
Requires watchOS 10.0 or later.
- iPhone
- Languages
- English
- Age Rating
4+
- 4+
- Copyright
- © Roy Jageman 2026
