They are not competing names for the same thing
PMR446 describes a short-range radio service and the conditions equipment must meet to use it licence-exempt in the UK. DMR, or Digital Mobile Radio, is a way of encoding digital voice and data between compatible radios. One term is about the service; the other is about the radio technology.
Why two radios may not understand one another
Most familiar PMR446 handsets use analogue FM. A digital DMR radio sends voice in a digital format, so an ordinary analogue set will not decode it. They may use nearby parts of the same broad frequency band, but that does not make the audio compatible. Both radios need to use a compatible mode and the same channel settings.
There are digital PMR446 radios designed for the licence-exempt service. That does not mean every commercial DMR radio qualifies. Power, antenna, channel plan and the exact model all matter. Check the specific UK version before transmitting; a radio being programmable to 446 MHz is not enough on its own.
What a DMR setup involves
With two matching analogue handsets, you can usually select the same channel and talk. A DMR radio may ask for a digital channel, colour code, time slot and talk group. Those settings have to match at both ends. Some people enjoy setting this up and learning what each option does; if your aim is a quick family or local chat, it is worth checking whether the extra setup suits you.
Which one should you choose?
If you want to join local activity already listed on PMRMap, an analogue FM PMR446 handset is the simplest starting point. Ask the group which channel and mode it uses before buying anything more specialised. If you later want to explore digital radio, find a group using the same system and learn its settings together.
Our channel guide covers the analogue plan, while the beginner’s guide walks through a first call. PMRMap’s store suggestions focus on analogue FM PMR446 handsets.
If a DMR radio is already in your cupboard, check its exact model and current configuration before assuming it is suitable for PMR446. It may be possible to program a radio to a frequency without making it compatible with a PMR446 group or meeting the conditions for that service. Ask a knowledgeable UK radio retailer about the specific unit rather than relying on a generic “446 MHz capable” description.