Sessagesimale – Calculator

Sessagesimale is a calculator built for anyone working with base-60 values — angles, time, geographic coordinates, surveying, astronomy, and navigation. No more manual conversions between decimal and degrees/minutes/seconds: enter values exactly as you read them on a map, a measuring instrument or a stopwatch, and get the normalized result instantly.

FREE, WITH AN OPTIONAL UNLOCK
Download it free and get 15 calculations a day, in every mode. One purchase, no subscription, unlocks the full version: unlimited calculations, the compass, the Apple Watch app and Shortcuts actions. If you already bought the paid app, everything is already unlocked.

THREE MODES IN ONE APP
• Angle (° ' ") — with two sub-formats: DMS (degrees, minutes, seconds, e.g. 40° 42' 46") and DDM (degrees and decimal minutes, e.g. 40° 42.7667'), the standard used by many GPS receivers and in maritime/aeronautical navigation.
• Time (h m s) — for hours, minutes and seconds.
• Decimal — for a classic calculator experience.
The value converts automatically when you switch modes. Mode, DMS/DDM sub-format and memory are remembered on relaunch.

NATURAL FIELD-BY-FIELD ENTRY
A contextual key guides your input: tap • ' to move from degrees to minutes, • " for seconds. On seconds (or minutes in DDM) it becomes your language's decimal separator — a period in English, a comma in many other languages. The active field is always highlighted.

FULL ARITHMETIC
Addition and subtraction between sexagesimal values with automatic carrying (45' + 30' = 1° 15'), multiplication and division by a scalar, chained operations, repeat the last calculation with "=". Dividing by zero shows an explicit error instead of a silent, wrong result.

DUAL DISPLAY, ALWAYS VISIBLE
As you type in sexagesimal format, read the decimal equivalent in real time (and vice versa).

CONVERSIONS PANEL
One tap to see the current value in every format at once — DMS, DDM, time, decimal degrees, radians, gon, and the hours↔degrees (×15) conversion used in right ascension and time zones. Tap any row to copy it.

COMPASS (IPHONE) — FULL VERSION
Read the magnetic heading from your iPhone's magnetometer: a dial with the cardinal point (N, NE, E…) and the value to a tenth of a degree. Tap Use to bring it into the calculator as an angle. No permission required.

NORMALIZE AND RECIPROCAL BEARING
Press and hold the display in Angle mode: Normalize brings the angle into 0°–360° (−30° → 330°) and Reciprocal bearing adds 180°.

MEMORY & HISTORY
MC, MR, M+, M– keys with an always-visible indicator. Every calculation is added to a persistent history: tap an entry to reuse its result, swipe to delete it, share it all as text.

COPY, PASTE, SHARE
Copy the current value, paste one from the clipboard (it recognizes decimal formats with a period or comma, sexagesimal values with °, ', " or typographic symbols, and the 12:34:56 notation), share via the system sheet.

FOR IPAD AND MAC
Hardware keyboard supported: digits, operators, Return for the result, Esc to clear everything.

ADAPTIVE INTERFACE
Layouts for iPhone (portrait and landscape) and iPad, light and dark mode, three alternative icons, full VoiceOver support with contextual labels, haptic feedback. The (?) button opens the tutorial and the About page.

APPLE WATCH — FULL VERSION
On your wrist, even without your iPhone: a calculator with all three modes (Angle, Time, Decimal), the four operations, DMS/DDM format, a history of recent calculations and a conversions panel. A compact keypad designed for the small display, with haptic feedback. The watch's history and settings are independent from those on your iPhone.

SHORTCUTS — FULL VERSION
Two actions for the Shortcuts app, Spotlight and Siri: Convert angle and Calculate. They run in the background, without opening the app.

PRIVACY
Works offline. No account, no data collection. The only connection is to the App Store, for the unlock purchase. History and memory stay on your device only.