Mexico uses 127V at 60Hz as its standard household electrical supply. If you're moving appliances between Mexico and North America (120V/60Hz), both voltage and frequency are worth checking before you plug anything in.
The good news: Mexico runs on 60Hz, the same frequency used in the United States and Canada. That means motors, clocks, timers, and other frequency-sensitive appliances will run at the correct speed without a dedicated frequency converter. In most cases a voltage transformer alone is enough to handle the 127V vs. 120V difference — a full frequency converter isn't required for equipment moving between Mexico and North America.
Frequency conversion still matters if you're bringing appliances designed for a 50Hz country (most of Europe, Africa, and Asia) into Mexico, or taking Mexico-spec appliances onward to a 50Hz destination.
Since Mexico runs at 127V, a US-spec 120V appliance needs its voltage stepped down before it can be used safely there — and a local 127V appliance needs its voltage stepped up to run on North American 120V power.
A plug adapter only changes the physical shape of the plug — it doesn't change voltage or frequency at all. If the appliance isn't rated for Mexico's 127V/60Hz supply, a plug adapter alone can damage it.
No — check the rating label on the back or bottom of each appliance. Many modern electronics (phone chargers, laptops) are dual-voltage and frequency-tolerant. Motor-driven and timing-based appliances are the ones that need real conversion.