# What is my time zone? What the detector shows, where it gets it, and how to read the results

> How the time zone detector reads your device's time zone, what each field means (IANA name, UTC offset, abbreviation, daylight saving status), how its daylight saving check works and where it can be wrong, and what to do when the result looks off.

- Tool: [What is My Timezone?](https://toolsg.com/en/timezone-detector)
- Language: en (available: en, zh, ms, ta)
- Last verified against official sources: 2026-10-18
- Source site: ToolSG — a planning guide, not official or financial advice. Cite the agencies listed under Sources.

## Key figures at a glance

| Fact | Value | Source |
| --- | --- | --- |
| Where the result comes from | Your browser, which takes it from your device's time zone setting — The page calls the browser's Intl API and makes no request to a server, to your IP address or to a location service. If your device is set to the wrong zone, the page shows the wrong zone. | [MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/DateTimeFormat/resolvedOptions) |
| IANA time zone name | A region/city name such as Asia/Singapore — This is the value the Copy Timezone button puts on your clipboard. It carries the zone's daylight saving rules; an offset on its own does not. | [MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/DateTimeFormat/resolvedOptions) |
| Singapore | Asia/Singapore, UTC+8, no daylight saving time |  |
| Abbreviation field | Often GMT+8 rather than letters — The page asks the browser for the short English zone name. For many zones, including Singapore, this is a form like GMT+8 rather than a code like SGT. | [MDN](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/DateTimeFormat/DateTimeFormat) |
| Daylight saving check | Compares your offset now with the offsets on 1 January and 1 July — It says active when the current offset is the larger of the two. This is an estimate, not a lookup in the time zone database. |  |

## Checking and fixing a wrong time zone: step by step

A wrong time zone shifts every timestamp, meeting and log line, so check it before you rely on it.

1. **Open the page and read the result** (Right away) — Look at the IANA name first. It should be the region where you are, for example Asia/Singapore.
2. **Compare the time with a trusted clock** (If something looks off) — If the time is an exact number of hours out, the time zone is wrong. If it is a few minutes out, the clock needs to be synchronised.
3. **Change the time zone in your device settings** (If the zone is wrong) — Use your operating system's date and time settings, and either choose the zone by hand or switch on automatic time zone.
4. **Reload or press Refresh** (After changing it) — The page re-reads the zone every second. If it still shows the old zone, reload the page.
5. **Copy the IANA name for your software** (When you need to configure something) — Press Copy Timezone and paste the identifier into your application, server or calendar. Tools: [World Clock](https://toolsg.com/en/world-clock)

## What the page shows

When it loads, the detector reads your time zone from the browser and shows it, refreshing every second. Nothing is typed in and nothing is sent anywhere.

| Field | Meaning |
| --- | --- |
| Timezone Name | The full English name, such as "Singapore Standard Time" |
| UTC Offset | How far your clock is from UTC right now, such as UTC+8 or UTC+5:30 |
| Current Time and Date | Your device's time and date, in your browser's usual format |
| IANA Timezone Identifier | The region/city name your device is set to, such as Asia/Singapore |
| Timezone Abbreviation | The short English name the browser gives, often a form like GMT+8 |
| Daylight Saving Time | Whether the page estimates that daylight saving time is in effect |

The Copy Timezone button copies the IANA identifier. Refresh re-reads the values straight away.

## Where the answer comes from

The browser has a time zone for the device, taken from the operating system's setting, and the page reads it with `Intl.DateTimeFormat().resolvedOptions().timeZone`. MDN describes the value as an IANA time zone name, defaulting to the runtime's default time zone. This is **not** found from your IP address or GPS, so a VPN does not change it by itself, but changing the device's own setting does. Some privacy settings report a different zone on purpose: Firefox with its `privacy.resistFingerprinting` setting turned on uses UTC as its time zone, whatever your device is set to. If the result does not match your device, check for a setting like that.

## Examples

What a current browser reports for different devices on 19 October 2026, with English names:

| Device set to | UTC offset | Name | Abbreviation field | DST shown |
| --- | --- | --- | --- | --- |
| Asia/Singapore | UTC+8 | Singapore Standard Time | GMT+8 | Not active |
| Asia/Kolkata | UTC+5:30 | India Standard Time | GMT+5:30 | Not active |
| Asia/Kathmandu | UTC+5:45 | Nepal Time | GMT+5:45 | Not active |
| Europe/London | UTC+1 | British Summer Time | GMT+1 | Active |
| America/New_York | UTC-4 | Eastern Daylight Time | EDT | Active |
| Australia/Sydney | UTC+11 | Australian Eastern Daylight Time | GMT+11 | Active |

Names and abbreviations come from your browser, so wording can differ a little between browsers.

## UTC offsets

An offset is how far the local clock is ahead of (+) or behind (-) UTC. It is not always whole hours: India is +5:30, Nepal +5:45. The offset changes when a place starts or ends daylight saving time, so an offset alone does not identify a time zone. For example, UTC+1 could be London in summer, or Paris in winter.

## How the daylight saving check works

The page does not look up the zone's rules. It reads your offset today and on 1 January and 1 July of the current year. If today's offset is the larger one and differs from the smaller one, it reports "Active". This works for most places, including both hemispheres, but it is an estimate. It can be wrong for zones that changed their standard offset during the year, or that follow unusual arrangements. Treat it as a quick hint, and use the [world clock](https://toolsg.com/en/world-clock) to see how offsets change through the year.

## For developers

- Store moments as UTC (or an offset-aware timestamp) and keep the IANA name separately, so you can show local time correctly later.
- Do not store only an offset such as "+01:00": it does not tell you what the offset will be after the next clock change.
- Use the full IANA name, not an abbreviation. "CST" can mean Central Standard Time (UTC-6), China Standard Time (UTC+8) or Cuba Standard Time (UTC-5).

## Common mistakes

- **Expecting a letter code like "SGT".** The abbreviation box may show GMT+8.
- **Thinking a VPN changes it.** The zone comes from the device setting, not the network.
- **Assuming "DST: Not Active" proves a zone has no DST.** It only says the offset is not the larger one this year.
- **Using the offset as the zone.** Use the IANA name.
- **Ignoring a clock that is a few minutes off.** That is a synchronisation problem, not a time zone problem.

## Related tools

- [World clock](https://toolsg.com/en/world-clock) — see the time in many cities and how offsets change.
- [Meeting time optimizer](https://toolsg.com/en/meeting-time-optimizer) — find shared working hours across time zones.
- [What is my IP address](https://toolsg.com/en/what-is-my-ip) — a different question: the address your connection uses.
- [Unix timestamp converter](https://toolsg.com/en/unix-timestamp-converter) — convert a timestamp into a date in any zone.

## Frequently asked questions

**How does the timezone detector work?**

The timezone detector uses your web browser's built-in JavaScript API (specifically Intl.DateTimeFormat().resolvedOptions().timeZone) to automatically identify your timezone. This information comes from your device's system settings and is available to the browser without requiring any special permissions or sending data to external servers.

**Can I detect someone else's timezone?**

No, this tool only detects the timezone of the device you're currently using. For privacy and security reasons, websites cannot directly detect the timezone of other users without them visiting your website.

**Why is my timezone different from my location?**

Your timezone is determined by your device's system settings, not your physical location. If you've manually set your device to a different timezone, the detected timezone will reflect your system settings rather than your GPS location.

**Does using a VPN change my detected timezone?**

No, VPNs change your IP address but not your system timezone. The timezone detector reads from your device's local settings, so the detected timezone remains the same regardless of VPN usage.

**What is the difference between UTC offset and timezone?**

A UTC offset (e.g., UTC+8) tells you how many hours ahead of or behind UTC, but multiple regions can share the same offset with different DST rules. The IANA timezone identifier (e.g., "Asia/Singapore") provides the complete and unambiguous timezone definition.

**Why is Daylight Saving Time important?**

Daylight Saving Time (DST) affects the actual UTC offset during certain months. For example, New York is UTC-5 in standard time but UTC-4 during daylight time. Knowing DST status is crucial for accurate time conversions.

**Is my timezone information private?**

Yes, all timezone detection happens locally in your web browser using JavaScript. No data is transmitted to external servers, ensuring complete privacy.

**Can I change the detected timezone?**

The tool displays your current system timezone. To see a different timezone, you need to change your device's system timezone settings and refresh the page.


## Sources

- [MDN — Intl.DateTimeFormat.prototype.resolvedOptions()](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/DateTimeFormat/resolvedOptions) — timeZone is an IANA time zone name; the default is the runtime's default time zone.
- [MDN — Intl.DateTimeFormat (timeZoneName option)](https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Intl/DateTimeFormat/DateTimeFormat) — short and long forms of the time zone name, such as PST, GMT-8 and Pacific Standard Time.
- [IANA — Time Zone Database](https://www.iana.org/time-zones) — The database of zone names and rules that operating systems and browsers use.
- [Mozilla Bugzilla 1330890 — Use UTC timezone when privacy.resistFingerprinting = true](https://bugzilla.mozilla.org/show_bug.cgi?id=1330890) — Why Firefox reports UTC when fingerprinting resistance is on.