# Sextant Calculator

> Celestial navigation sight reduction calculator for angles and times. (iPhone/iPad app by Will Downing.)

- Source: https://appshunter.io/ios/app/sextant-calculator/id6757097850 (this page in markdown: same URL + `.md`)
- Developer: [Will Downing](https://appshunter.io/developer/1864501052)
- Category: Navigation, Education
- Price: $1.00
- Age rating: 4+
- Requires: iOS 13.0 · 2 MB
- Languages: American English
- Released: 2026-01-13
- Data updated: 2026-08-08
- Monetization: paid
- User reviews in markdown: https://appshunter.io/ios/app/sextant-calculator/id6757097850/reviews.md

## What is Sextant Calculator?

Sextant Calculator is the essential tool for celestial navigators, designed to simplify the arithmetic of sight reductions.

FEATURES

- Angle Calculations
Enter angles in degrees and decimal minutes (DD° MM.m') format. Add, subtract, or divide angles with a single tap. Perfect for working through sun, star, and planet sights.

- Time Calculations
Work with hours, minutes, and seconds. Add and subtract times for GMT calculations, zone time conversions, and chronometer checks. Results automatically handle overflow into days when needed.

- Averaging Made Simple
Use the divide function to quickly calculate the average of multiple sights. Enter your total, divide by the number of observations, and get your mean position.

- Purpose-Built Keypad
A custom colour-coded keypad designed specifically for navigation calculations. No fumbling with a standard calculator - every button has a purpose.

- Day and Night Modes
Switch to red night mode to preserve your dark adaptation during night watches. Essential for practical celestial navigation at sea.

- Results Tape
See your complete calculation history in the scrollable results display. Review your work and catch errors before they affect your position.

DESIGNED FOR NAVIGATORS

Whether you're a yacht skipper crossing an ocean, a merchant marine officer maintaining traditional skills, or a student learning celestial navigation, Sextant Calculator removes the tedium from sight reduction arithmetic.

No more mental arithmetic errors. No more reaching for pencil and paper. Just clean, accurate calculations every time.

Works offline - no internet connection required. Your navigation calculations work wherever you are, from mid-ocean to the most remote anchorage.

## Key features

- Angle calculations in DD° MM.m'
- Time calculations with H:M:S
- Average multiple sights
- Custom color-coded keypad
- Day and night modes
- Scrollable results tape
- Offline functionality

## Recent user reviews (1 of 1)

All indexed reviews: https://appshunter.io/ios/app/sextant-calculator/id6757097850/reviews.md

### 5/5 — Amazing app

*2026-01-20*

Really helpful who ever created this is really smart thanks a lot this is really helpful

## Frequently asked questions about Sextant Calculator

### What is Sextant Calculator used for?

Sextant Calculator is designed to simplify the arithmetic involved in celestial navigation sight reductions. It helps users perform angle and time calculations, average multiple sights, and manage chronometer checks without manual errors.

### How does Sextant Calculator handle angles?

You can enter angles in degrees and decimal minutes (DD° MM.m') format. The app allows for easy addition, subtraction, and division of these angles, which is crucial for working with sun, star, and planet sights.

### Can Sextant Calculator be used offline?

Yes, Sextant Calculator works offline, meaning no internet connection is required. This makes it a reliable tool for navigation calculations even when you are at sea or in remote locations without connectivity.

### What makes Sextant Calculator's keypad special?

The app features a custom, color-coded keypad specifically designed for navigation calculations. This purpose-built interface ensures that each button has a dedicated function, preventing the need to fumble with a standard calculator.

### Does Sextant Calculator have a night mode?

Yes, Sextant Calculator includes a red night mode. This feature is essential for practical celestial navigation at sea, as it helps preserve your dark adaptation during night watches.

### How much does Sextant Calculator cost?

Sextant Calculator is available for a one-time purchase price of $1.00. This one-time payment grants you full access to all its features without any recurring fees or subscriptions.

### What devices does Sextant Calculator support?

Sextant Calculator is supported on iPhone and iPod devices. It is designed to provide a seamless experience on these Apple mobile platforms.

### Does Sextant Calculator have ads?

No, Sextant Calculator does not contain advertisements. As a paid application, it offers an uninterrupted user experience free from any in-app ads.

## Version history (last 1 release)

### 1.0 — 2026-01-13

No release notes.

## Apps similar to Sextant Calculator

| App | Rating | Price | Category |
| --- | --- | --- | --- |
| [Anchor Alarm - Boat Tracker](https://appshunter.io/ios/app/anchor-alarm-boat-tracker/id6450539229) | 4.2 (5) | Free | Navigation |
| [COLREG](https://appshunter.io/ios/app/colreg/id6446209111) | — | $0.99 | Navigation |
| [Nautical Calculator Pro](https://appshunter.io/ios/app/nautical-calculator-pro/id1455851003) | 5.0 (3) | $8.99 | Navigation |
| [AngelNav](https://appshunter.io/ios/app/angelnav/id1583349534) | 5.0 (2) | Free | Navigation |
| [Celestial Navigation 360](https://appshunter.io/ios/app/celestial-navigation-360/id6747285959) | — | Free | Navigation |
| [Safety Anchor Alarm](https://appshunter.io/ios/app/safety-anchor-alarm/id6756064994) | 1.0 (1) | Free | Navigation |

## More apps by Will Downing

- [HMS ColRegCards](https://appshunter.io/ios/app/hms-colregcards/id6759050269)
- [Potty Dotty](https://appshunter.io/ios/app/potty-dotty/id6759102062)
- [Wordnest - A Fun Word Game](https://appshunter.io/ios/app/wordnest-a-fun-word-game/id6759271501)

All apps by Will Downing: https://appshunter.io/developer/1864501052

---

*Data collected daily from the US App Store and indexed by [AppsHunter](https://appshunter.io/). User reviews are verbatim App Store reviews. Ratings, prices and chart positions refresh continuously; this snapshot is from 2026-08-08.*