timecalc

A time calculator written in Rust, available as both a GUI app and a CLI tool.

Features

• Add, subtract, multiply, and divide time values in HH:MM:SS or MM:SS or raw seconds format
• GUI — compact desktop calculator window built with egui
• CLI — interactive terminal session for quick calculations

Requirements

• Rust (edition 2024)
• Cargo (included with Rust)

Installation

Clone the repository and build with Cargo:

git clone https://github.com/craigmjackson/timecalc.git
cd timecalc
cargo build --release

By default, both the GUI and CLI binaries are built. The compiled binaries will be at:

• ./target/release/timecalc-gui
• ./target/release/timecalc-cli

To build only one of them:

cargo build --release --no-default-features --features gui
cargo build --release --no-default-features --features cli

Usage

GUI

Launch the desktop calculator:

./target/release/timecalc-gui

The GUI displays a compact calculator window. Enter a time value using the keypad, then choose an operator (+, -, x, ÷) and a second time value, and press = to calculate. The display shows the running result and current expression.

Keyboard shortcuts:

Key	Action
0–9, : or .	Enter time digits / separator
+, -, * or x, /	Set operator
Enter	Calculate
Escape	Clear (AC)
Cmd+Q	Quit

CLI

Launch the interactive CLI session:

./target/release/timecalc-cli

The CLI starts at 00:00:00 and accepts one operation per line in the format <operator> <time>. Type exit or quit to close.

Example session:

Starting time: 00:00:00
> + 1:30:00
01:30:00
> + 45:00
02:15:00
> - 0:30
01:45:00
> / 3
00:35:00
> exit

Time Format

Times can be entered in any of the following formats:

Format	Example	Interpreted as
HH:MM:SS	1:30:00	1 hour, 30 minutes
MM:SS	45:30	45 minutes, 30 seconds
Raw seconds	3600	1 hour

Building & Testing

# Run tests
cargo test

# Build debug
cargo build

# Build release
cargo build --release

# Cross-compile Windows build on non-Windows machine
rustup target add x86_64-pc-windows-msvc
cargo install cargo-xwin
cargo xwin build --release --target x86_64-pc-windows-msvc

License

See the repository for license details.