UTC to GMT Converter
Convert UTC to GMT and BST (British Summer Time). See the difference between UTC and GMT. GMT is UTC+0 in winter, BST is UTC+1 in summer.
Built by Michael Lip
Frequently Asked Questions
Is UTC the same as GMT?
In practice, UTC and GMT show the same time (UTC+0). However, UTC is a time standard based on atomic clocks, while GMT is a timezone used in the UK during winter. The UK switches to BST (UTC+1) in summer, so GMT and UTC only match from late October to late March.
What is BST (British Summer Time)?
BST is UTC+1, used in the UK from the last Sunday in March to the last Sunday in October. During BST, London is 1 hour ahead of UTC. The rest of the year, the UK uses GMT which equals UTC+0.
Why do developers confuse UTC and GMT?
Many programming languages and APIs use GMT and UTC interchangeably. JavaScript's Date.toGMTString() returns UTC time. HTTP headers use 'GMT' in date fields but mean UTC. For all practical software purposes, GMT=UTC+0, but always use UTC in code to avoid ambiguity with BST.
Which countries use GMT?
The UK (winter only), Iceland (year-round), Portugal (mainland, winter only), Ghana, Ivory Coast, Senegal, and several other West African countries use GMT (UTC+0). Ireland uses IST (Irish Standard Time, UTC+1) in summer and GMT in winter.
Is this tool free?
Yes. All EpochPilot tools are free, run in your browser, and require no signup or account.
How It Works
This converter uses the IANA timezone Europe/London, which automatically accounts for the UK's BST/GMT transitions. During winter months, UTC and London time are identical. During summer (last Sunday in March to last Sunday in October), London time is UTC+1.
The distinction matters for developers because many APIs and protocols use "GMT" when they technically mean UTC. The HTTP Date header, for example, always uses "GMT" but represents UTC. JavaScript's deprecated toGMTString() returns UTC. When in doubt, treat "GMT" in technical contexts as UTC+0 and use this converter to see actual London local time.
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Privacy
Everything runs locally in your browser. No data is transmitted to any server. Source code is open on GitHub.
Contact
EpochPilot is built by Michael Lip. Email [email protected] for feedback.