Flight Day/Night Calculator

Offline UTC day/night flight-time calculation for pilots. Free core A–B results, with optional Pro tools for waypoints, exports, and local-time entry.

Flight Day/Night Calculator is an offline UTC-based tool for calculating day and night flight time. Built by an airline pilot for pilots at every stage, from first night cross-country to long-range operations at high latitudes, it helps produce clear, repeatable results for logbook use.

The core A-to-B calculation engine is fully available in the free tier. Optional Pro features add workflow tools and modelling refinements for more complex operations, without changing the underlying calculation engine.

Why This App?

Aviation authorities require accurate day and night flight time splits, but calculating them precisely is difficult without specialised tools. The sun’s position changes continuously along your route, and day/night boundaries shift with latitude, season, routing, and timing.

Flight Day/Night Calculator makes these calculations transparent and repeatable. It works offline for calculations and airport lookup, with an on-device airport database and embedded astronomy algorithms.

No guesswork. No manual plotting. No sign-in. No data collection. Just clear UTC-based results you can review, export, and log with confidence.

How It Works

The app computes your aircraft’s position minute by minute using your departure, destination, and optional Pro waypoints. At each point it determines the sun’s elevation angle and classifies day and night using the standard civil twilight definition: sun at or above −6°.

Results are UTC-authoritative. Local Time Entry, where available, uses manually selected UTC offsets for input convenience only. The app does not use automatic timezone or DST detection.

Pro displays for nautical twilight, astronomical twilight, and altitude-adjusted sunrise/sunset provide additional situational awareness. Regulatory day/night totals remain based on civil twilight.

Free includes:

• Direct A-to-B day/night calculation
• Minute-by-minute civil twilight classification
• Great-circle routing
• Offline airport search and lookup
• Custom coordinate entry
• Block time (OOOI) and airborne calculations
• Distance and average groundspeed
• Estimated Uncertainty
• High-latitude cautions
• Input validation
• Full results display

Pro adds:

• Waypoint routing, up to 20 waypoints
• Waypoint ATA timing refinement
• Local Time Entry using manual UTC offsets
• Altitude-adjusted sunrise and sunset
• Nautical and astronomical twilight display
• History access
• Export-ready text and CSV export
• Logbook notes options
• Advanced twilight display controls

Key Features

• UTC-based calculations, results, and exports
• Offline airport database
• ICAO entry with confirmation
• Search by ICAO, IATA, local identifier, or name
• Custom departure, arrival, and location coordinate entry
• Detailed transition events with times and coordinates
• Results in hours:minutes and decimal hours
• Distance in nautical miles and average groundspeed in knots
• Estimated Uncertainty to highlight twilight sensitivity
• Validation for implausible route and waypoint timing
• Designed for iPhone and iPad, including Split View
• Light and Dark Mode support

Privacy & Offline Use

Flight calculations, airport lookup, route processing, astronomy, results, and exports are performed on device.

The app does not require an account and does not collect personal data.

Purchases, subscriptions, restores, and entitlement verification are handled through Apple StoreKit.

Subscription & Purchase Information

Optional Pro access is available as:

• Pro Monthly — auto-renewing subscription
• Pro Annual — auto-renewing subscription
• Pro Lifetime — one-time purchase

Pricing is shown in-app and may vary by region. Payment is charged to your Apple ID at confirmation of purchase.

Subscriptions renew automatically unless cancelled at least 24 hours before the end of the current period. Manage or cancel subscriptions in App Store settings.

Terms of Use: https://www.apple.com/legal/internet-services/itunes/dev/stdeula/