If you travel often or power devices across borders, you’ve likely encountered different voltages and frequencies. Modern chargers are designed for global use, typically labeled Input: 100-240V ~ 50/60Hz. This means a single charger can work in most countries without a heavy transformer, making travel and international work far more convenient.   Understanding the numbers. North America and Japan commonly use 100-120V, 50/60Hz, while Europe, many Asian regions, and Australia typically use 230V, 50Hz. The key is the input range. When a charger says 100-240V, it’s compatible with these standards; you’ll just need the right plug adapter for the outlet shape.     Why the input range matters. A charger that accepts 100-240V eliminates the need for bulky voltage converters. Always check the label or manual for “Input.” Also verify output compatibility (e.g., 5V/3A, USB-C PD) to ensure your device charges safely and efficiently across locations.   Tips for travelers. Choose chargers with universal input, multiple outputs, and safety certifications (ETL, CE, FCC, RoHS). Carry a compact travel adapter and consider models with foldable plugs.