ETA Calculator is a practical tool developed for maritime professionals to assist with voyage planning and time management at sea. It allows users to perform two primary types of calculations commonly used in navigation:

Estimated Time of Arrival (ETA):
- Enter the distance to the destination and the vessel’s speed to calculate the expected arrival time.

Required Speed:
- Enter the distance and the desired arrival time to calculate the speed needed to reach the destination on time.

These functions are useful for:
- Bridge watch officers
- Masters and chief officers
- Anyone involved in passage planning or time-critical maritime operations

Features:
- Works completely offline, no internet connection required.
- Simple and clear user interface, optimized for quick input and results.
- Supports both light and dark themes for day and night use.
- Uses 24-hour time format for consistency with maritime standards.

The application is intended for use on board vessels of any type and size, as well as during training and simulation exercises. It focuses on accuracy, reliability, and ease of use in real-world conditions.