Guide

315 MHz vs 433 MHz Car Keys: Which One Does My Car Use?

Last updated: September 2026 · Written for auto locksmiths & key distributors

Quick answer

Before ordering any replacement car key, remote or smart key, you need to know one thing: the radio frequency.

Before ordering any replacement car key, remote or smart key, you need to know one thing: the radio frequency. Most replacement keys sold online fail for a simple reason - the buyer picked the right model but the wrong frequency. This guide explains the difference between 315 MHz and 433 MHz keys and how to check yours in under a minute.

Not sure about your key? Send a photo on WhatsApp - free identification, usually within minutes.

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Why frequency matters

Your key remote talks to the car on a specific radio frequency. If the key and the car are not on the same frequency, nothing happens - no lock/unlock, no boot release, no start. Frequency cannot be 'reprogrammed' on most remotes; it is fixed in the hardware, so getting it right at order time is the whole game.

Which frequency is most common in Europe and Australia?

433.92 MHz (usually written as 433 MHz) is the standard for the vast majority of European and Australian market vehicles, including VW, Audi, BMW, Mercedes, Ford, Opel/Vauxhall, Peugeot, Renault, Toyota, Holden and Mazda.

315 MHz is mainly found on North American market vehicles and some Japanese domestic models. If you are a locksmith in the UK, Europe or Australia buying trade stock, 433 MHz will cover most of your jobs - but always verify the individual car.

How to check your key's frequency

Method 1 - the sticker: many remotes have a small label or printed marking inside the battery compartment or on the back showing '433.92 MHz', '315 MHz' or an FCC/CE ID you can look up.

Method 2 - the car's region: a car sold new in Europe, the UK or Australia is almost always 433 MHz. A grey import from the US or Japan may be 315 MHz.

Method 3 - just send a photo: take a clear picture of your key (front, back, and the inside of the battery cover) and send it to us on WhatsApp. We identify the frequency, chip and correct replacement for free.

Does frequency affect smart keys too?

Yes. Smart keys (keyless entry / push-to-start) also operate on 433 MHz or 315 MHz depending on the market. The same 'match the frequency first' rule applies before you invest in programming.

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