# Block Time Calculator

> HH:MM time calculator for pilots. Adds and subtracts flight and duty time in hours and minutes with automatic 60-minute rollover, so 01:45 + 00:30 = 02:15, not 01:75. Available for iPhone, iPad and Android, with a free web version on the home page.

Block Time Calculator (home-screen name "Block Time") is a minimalist calculator for auditing and totalling pilot logbooks. It is made by İnanç Atil. It costs US$0.99 as a one-time purchase, with no subscription, no in-app purchases and no ads. It works fully offline, makes no network connections and collects no data.

## How it works

- **ATM-style input**: there is no colon key. Digits fill in from the right: typing 4, 1, 5 gives 04:15.
- **Base-60 math**: minutes roll over at 60 when adding and borrow at 60 when subtracting (05:15 − 00:45 = 04:30).
- **Result retention**: after =, the total stays on screen, so the next leg can be added straight away. C clears the equation.
- **History**: every result is listed with its formula; tapping a row brings that calculation back.
- **No 24-hour cap**: hours keep counting past 24, so logbook page and career totals add up (186:40 + 07:35 = 194:15).
- **Negative results** are shown with a minus sign (00:30 − 01:00 = −00:30).
- **Across midnight**: add 24:00 to the on-block time, then subtract the off-block time (01:10 + 24:00 − 22:45 = 02:25).

## App features

- Running tape: every operand on its own numbered line with a running subtotal, beside the history. Subtractions are marked in red.
- Operand editing: tap a line on the tape to change it, or tap its operator to flip + and −, without retyping.
- High-contrast dark and light themes for night and day flying.
- Tablet layout: a full-height history pane next to a larger tape and keypad (iPad and Android tablets).
- Haptic key feedback.
- Requirements: iOS 15.1 or later on iPhone and iPad; Android phones and tablets.

## Pages

- [Home and web calculator](https://inancdev.github.io/BlockTimeCalculatorWeb/): working HH:MM calculator, examples, app features and FAQ.
- [Support](https://inancdev.github.io/BlockTimeCalculatorWeb/support.html): contact and FAQ.
- [Privacy Policy](https://inancdev.github.io/BlockTimeCalculatorWeb/privacy.html): no data collected; nothing leaves the device.

## Download

- [App Store (iPhone and iPad)](https://apps.apple.com/app/block-time-calculator/id6770303845)
- [Google Play (Android)](https://play.google.com/store/apps/details?id=com.inancatil.blocktimecalculator)

## Contact

- Email: inancdev@gmail.com