Timezone Dissonance Test
Free IP vs Browser Timezone Check
Run our free timezone dissonance test to check if your IP timezone matches your browser system time. This browser timezone mismatch checker uses Intl.DateTimeFormat and getTimezoneOffset to detect VPN location mismatches, proxy fingerprinting signals, and timezone spoofing. A mismatched timezone is a primary signal used for bot detection scoring and fraud prevention.
Quick Answer: What Is Timezone Dissonance?
Timezone dissonance occurs when your IP address geolocation timezone does not match the timezone reported by your browser via JavaScript Intl.DateTimeFormat. This mismatch signals VPN or proxy use because VPNs change your IP location but cannot change your system clock. Anti-fraud engines, banks, and streaming services use this mismatched timezone detection to flag non-residential traffic with fraud prevention signals.
IP vs Browser Timezone Check
Click below to compare your IP geolocation timezone against your browser system time using Intl.DateTimeFormat and getTimezoneOffset.
Analyzing temporal markers...
Querying Intl.DateTimeFormat...
IP Timezone
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Browser Timezone
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UTC Offset Diff
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Dissonance Result
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Summary
Jessica Wright
Cybersecurity Threat Researcher
Jessica specializes in temporal forensics, VPN leak detection, and proxy fingerprinting techniques. She helps security teams and privacy-conscious users understand how timezone dissonance, clock skew, and DST mismatches expose real locations behind VPNs and anti-detect browsers.
View All Articles by Jessica WrightWhat Is a Timezone Dissonance Test and Why Does It Matter?
A timezone dissonance test compares two data points that should match but often do not: the timezone derived from your IP address geolocation and the timezone reported by your browser via JavaScript Intl.DateTimeFormat. When these timezones disagree, it creates a "dissonance" that signals VPN use, proxy connections, or timezone spoofing.
This mismatched timezone detection is one of the most reliable fraud prevention signals available. Anti-fraud engines at banks, e-commerce platforms, and streaming services use it as a primary scoring factor. According to the IANA Time Zone Database (Wikipedia), there are over 400 timezone identifiers worldwide. When your IP says "America/New_York" but your browser reports "Asia/Kolkata," the mismatch is unmistakable.
Our free browser timezone mismatch checker runs this exact comparison in real time. It reads your browser's Intl.DateTimeFormat output, compares it against your IP's expected timezone, calculates the UTC offset difference, and checks for DST (Daylight Saving Time) inconsistencies.
Key Fact: Research by anti-fraud companies shows that timezone dissonance alone catches over 60% of basic VPN and proxy users. When combined with IP fraud scoring and JA3 TLS fingerprinting, detection accuracy reaches 99%.
How Websites Detect Proxies via Timezone Dissonance
Understanding the technical mechanism behind timezone dissonance detection explains why VPNs fail to mask your real location. The process happens in two parallel steps — one server-side, one client-side.
Step 1: Server-Side IP Geolocation
When you visit a website, the server sees your IP address. It queries a GeoIP database (like MaxMind GeoLite2) to determine your expected location and timezone. For example, IP 203.0.113.50 might resolve to "Asia/Karachi" (UTC+5). This is the IP timezone.
Step 2: Client-Side JavaScript Probe
Simultaneously, the website runs JavaScript code that reads your browser's timezone directly from your operating system.
// JavaScript: How websites read your timezone
// Method 1: IANA timezone name
const tz = Intl.DateTimeFormat().resolvedOptions().timeZone;
// Returns: "America/New_York", "Asia/Kolkata", etc.
// Method 2: UTC offset in minutes
const offset = new Date().getTimezoneOffset();
// Returns: 300 (for UTC-5), -330 (for UTC+5:30)
// Method 3: DST detection
const jan = new Date(2026, 0, 1).getTimezoneOffset();
const jul = new Date(2026, 6, 1).getTimezoneOffset();
const hasDST = jan !== jul;
Step 3: Comparison and Scoring
The server compares the IP timezone against the browser timezone. If they match, the connection appears legitimate. If they differ, the system adds risk points to your bot detection scoring profile. A 1-hour difference might be natural (DST edge case). A 10-hour difference is definitive proof of VPN or proxy use.
For a related check, test whether your IP is flagged as a proxy or VPN with our IP Fraud Score Checker.
Why Does My Browser Show a Different Timezone Than My IP?
The most common cause of timezone dissonance is using a VPN or proxy. Here is exactly why this happens and why VPNs cannot prevent it.
VPNs Operate at the Network Layer
A VPN encrypts your traffic and routes it through a server in another country, giving you a new IP address. However, VPNs operate at OSI Layer 3 (Network) and Layer 4 (Transport). They have zero access to your operating system's clock settings, which live at the application layer. Your system time remains set to your real physical location.
JavaScript Reads the Local Clock
When a website calls Intl.DateTimeFormat or getTimezoneOffset, the browser reads your OS clock directly. This data never travels over the network — it is read locally inside the browser. The VPN tunnel cannot intercept, modify, or even see this process.
Common Dissonance Scenarios
- VPN User: IP says "US/New York" but browser reports "Europe/London" — VPN location mismatch detected.
- Proxy User: IP says "Japan/Tokyo" but browser reports "Asia/Kolkata" — clear proxy fingerprinting signal.
- Traveler: IP says "Germany/Berlin" and browser says "America/Chicago" — legitimate travel, but still flagged for review.
- Tor User: IP says exit node location but Tor Browser reports "UTC" — Tor's standardization eliminates dissonance.
Test your VPN's complete leak profile with our WebRTC Leak Test and DNS Leak Check.
How Timezone Dissonance Affects Bot Detection Scoring and Fraud Prevention
Anti-fraud systems do not rely on a single signal. They combine multiple data points into a composite trust score. Timezone dissonance is one of the highest-weight signals in this scoring model.
How the Scoring Works
| Signal | Risk Points | Detection Method |
|---|---|---|
| Timezone Dissonance (>3 hrs) | +40 points | Intl.DateTimeFormat vs IP GeoIP |
| Timezone Dissonance (1-3 hrs) | +20 points | May be DST or travel |
| VPN/Proxy IP Detected | +30 points | IP reputation database |
| JA3 Hash Mismatch | +15 points | TLS fingerprint analysis |
| Browser Fingerprint Anomaly | +15 points | Canvas, WebGL, fonts, battery |
When the total score exceeds 70-80 points, the system blocks the transaction, triggers a CAPTCHA, or flags the account for manual review. Timezone dissonance alone provides 20-40 points — often enough to push a suspicious connection over the threshold.
Check your current fraud risk with our IP Fraud Score Checker and your TLS identity with our JA3 Fingerprint Lookup.
How to Fix Timezone Dissonance When Using a VPN (2026)
If your timezone dissonance test shows a mismatch, here are proven methods to align your system time with your VPN location for legitimate use cases like remote work and privacy.
Method 1: Manual System Clock Change
# Windows: Change timezone via command line
tzutil /s "Eastern Standard Time"
# Verify:
tzutil /g
# macOS: Change timezone via terminal
sudo systemsetup -settimezone "America/New_York"
# List all available:
sudo systemsetup -listtimezones
# Linux: Change timezone
sudo timedatectl set-timezone America/New_York
timedatectl status
Method 2: Anti-Detect Browser Timezone Sync
Anti-detect browsers like Multilogin, AdsPower, and Kameleo can automatically sync the browser's reported timezone with the selected proxy location. This is called automatic timezone spoofing — the browser overrides Intl.DateTimeFormat and getTimezoneOffset to return values matching the proxy's geolocation.
Method 3: Tor Browser (UTC Standardization)
Tor Browser reports UTC (GMT+0) for all users worldwide, eliminating timezone dissonance entirely. Every Tor user has the identical timezone report. Check your Tor status with our Tor Detection Tool.
Important: Manual system clock change is the simplest fix but easy to forget — especially during DST transitions. Automatic timezone spoofing via anti-detect browsers is more reliable for ongoing use. Always run our timezone dissonance test after any change to verify alignment.
DST Mismatches and Clock Skew: Advanced Timezone Forensics
Beyond simple timezone comparison, advanced fraud prevention systems analyze DST (Daylight Saving Time) transitions and RTC (Real-Time Clock) synchronization patterns for deeper proxy fingerprinting.
The DST Trap
Imagine you are in London (GMT+0 winter / GMT+1 summer) using a New York VPN (EST/EDT). You manually set your clock to "New York time." But if New York switches to EDT (Daylight Saving) while London has not yet switched to BST, your clock will be off by exactly 1 hour for a few weeks. This 1-hour discrepancy during DST transition periods is a well-known mismatched timezone detection technique.
Clock Skew Analysis
RTC synchronization analysis measures the tiny drift between your system clock and the server's atomic time reference. Every computer's hardware clock has a unique drift pattern — typically a few milliseconds per day. Advanced forensic systems can use this clock skew as an additional fingerprint to identify a specific device even if it changes IP, browser, and timezone settings.
For checking other fingerprint vectors that survive VPN use, test your Canvas Fingerprint, Font Fingerprint, and Battery Status Leak.
Timezone Mismatch Test for Remote Workers and Freelancers
Remote workers and digital nomads face timezone dissonance as a daily reality. If you work for a US company while traveling in Southeast Asia, your VPN connects to a US server but your system clock reflects local time — creating a mismatch that can trigger security alerts on corporate platforms.
Common Remote Work Scenarios
- Freelancer on Upwork: Using a US VPN from Pakistan to access geo-restricted job listings. The platform detects timezone dissonance between US IP and Asia/Karachi browser time.
- Remote Employee: Working from Bali with a corporate VPN to London office. The HR system flags the mismatch between Europe/London IP and Asia/Makassar system time.
- Digital Nomad: Traveling through 3 countries in a month while maintaining a single VPN location. Each new country creates a different browser timezone mismatch.
Best Practices for Remote Workers
- Set your system timezone to match your VPN server location before logging into work platforms.
- Use an anti-detect browser profile with timezone spoofing configured to your employer's timezone.
- Run our timezone dissonance test before each work session to verify alignment.
- Inform your employer about your travel schedule to avoid false-positive security lockouts.
Check If Anti-Detect Browser Is Leaking Real Timezone
If you use anti-detect browsers like Multilogin, AdsPower, or Kameleo, verifying that timezone spoofing actually works is critical. Our timezone dissonance test is the definitive way to check.
What Anti-Detect Browsers Override
These browsers intercept JavaScript API calls to report a fake timezone. Specifically, they override Intl.DateTimeFormat().resolvedOptions().timeZone and new Date().getTimezoneOffset() to return values matching the proxy's geolocation. However, not all implementations are flawless.
Common Leak Points
- WebRTC leaks: Some anti-detect browsers correctly spoof timezone but leak the real IP via WebRTC, which reveals the true location. Test with our WebRTC Leak Detector.
- Performance API: The
performance.timeOrigintimestamp can reveal the real system time if the anti-detect browser does not override it. - Date constructor: Creating a new Date() object and checking its methods may bypass some timezone overrides.
- Intl.DateTimeFormat locale: The locale string returned alongside timezone can reveal language settings inconsistent with the spoofed location.
// Advanced timezone leak checks anti-detect browsers should handle:
// 1. Primary timezone (most browsers spoof this)
Intl.DateTimeFormat().resolvedOptions().timeZone
// 2. UTC offset (should match spoofed timezone)
new Date().getTimezoneOffset()
// 3. Date string output (often missed)
new Date().toString() // Contains timezone abbreviation
// 4. Performance origin (advanced check)
performance.timeOrigin // Real system timestamp
// 5. Intl locale detection
Intl.DateTimeFormat().resolvedOptions().locale
Pro Tip: After configuring your anti-detect browser profile, run our timezone dissonance test, then also check the browser console output for Date().toString() — if the timezone abbreviation in the date string does not match your spoofed timezone, advanced detection systems will catch the inconsistency.
How Netflix, Banks, and E-Commerce Use Timezone Dissonance
Major platforms have integrated timezone dissonance detection into their security and content delivery systems. Here is how different industries use this signal.
Streaming Services (Netflix, Hulu, Disney+)
Streaming platforms enforce geo-licensing by checking if your IP timezone matches your browser timezone. If your IP shows a US datacenter but your browser reports Asia/Tokyo, the player displays "Proxy Detected." This is a low-cost, high-accuracy method to enforce content licensing without maintaining massive VPN IP databases.
Banking and Financial Services
Banks use timezone dissonance as a high-weight fraud prevention signal. If a customer who normally logs in from London suddenly appears from a New York IP but with a Europe/London browser time, the system flags a potential account takeover and triggers additional verification (2FA, security questions, or temporary account lock).
E-Commerce Platforms (Amazon, eBay)
Online marketplaces use timezone mismatch data to prevent fraudulent purchases and account creation. Combined with device fingerprinting and payment location checks, timezone dissonance helps identify accounts operated from locations inconsistent with their registered addresses. Check your IP's reputation with our IP Blacklist Check.
Automatic Timezone Spoofing vs Manual System Clock Change
Two approaches exist for eliminating timezone dissonance. Each has trade-offs in terms of reliability, convenience, and detection risk.
| Feature | Manual Clock Change | Anti-Detect Spoofing |
|---|---|---|
| Method | Change OS timezone settings | Override JS APIs in browser |
| Scope | Affects entire system (all apps) | Affects only the browser profile |
| DST Handling | OS handles DST automatically | Depends on browser implementation |
| Clock Skew Risk | None (real system clock) | May leak via performance API |
| Convenience | Must change before each VPN session | Automatic per profile |
| Best For | Casual VPN users, remote workers | Multi-account management, research |
For casual VPN users and remote workers, manual system clock change is the simplest and most reliable solution. For multi-account operators and researchers, anti-detect browsers with automatic timezone spoofing provide better scalability. Use our proxy timezone alignment tool to verify either approach.
IANA Timezone Database and Fingerprint Entropy
The IANA Time Zone Database (also called the tz database or Olson database) defines over 400 timezone identifiers like "America/New_York" or "Asia/Kolkata." Your browser reports one of these identifiers via Intl.DateTimeFormat, and this value itself contributes to your fingerprint entropy.
Timezone as a Fingerprinting Signal
While there are only ~24 UTC offsets, the IANA identifiers are far more specific. "America/New_York" and "America/Detroit" share the same UTC offset but identify different geographic regions. Unusual timezones like "Asia/Kathmandu" (UTC+5:45) or "Pacific/Chatham" (UTC+12:45) immediately narrow the user to a small population, increasing fingerprint entropy significantly.
Combined with other fingerprinting signals — canvas hash, font list, screen resolution, and language settings — your timezone becomes part of a comprehensive digital fingerprint. For checking your complete fingerprint surface, use our Browser Leak Test.
Best Free Tool to Check Browser and System Time Consistency
Our timezone dissonance test is the most comprehensive free proxy timezone alignment tool available. Here is what our test checks and how to interpret each result.
What We Analyze
- IP Timezone (Server-Side): Your IP address is resolved to a geographic timezone using GeoIP databases. This is what the website expects your timezone to be.
- Browser Timezone (Client-Side): We read Intl.DateTimeFormat().resolvedOptions().timeZone and getTimezoneOffset() from your browser to see what your operating system reports.
- UTC Offset Difference: We calculate the hour/minute difference between the two timezones. Zero difference means perfect alignment.
- DST Analysis: We check whether both timezones are applying DST consistently. A 1-hour mismatch during DST transition periods is a known detection pattern.
- Risk Assessment: Based on the offset difference, we assign a risk level: Match (safe), Minor Mismatch (1-3 hours), or Critical Dissonance (3+ hours).
How to Use the Results
- Match (0 hours): Your IP timezone and browser timezone are aligned. No dissonance detected.
- Minor Mismatch (1-3 hours): Could be legitimate travel or DST edge case. Some systems may flag for review but not block.
- Critical Dissonance (3+ hours): Strong signal of VPN or proxy use. Most anti-fraud systems will flag or block this connection. Fix by changing your system timezone or using timezone spoofing.
Frequently Asked Questions About Timezone Dissonance
What is a timezone dissonance test?
A timezone dissonance test compares your IP timezone (from geolocation) against your browser timezone (from Intl.DateTimeFormat). A mismatch signals VPN, proxy, or timezone spoofing — a key fraud prevention signal.
Why does my browser show a different timezone than my IP?
VPNs change your IP location but cannot change your system clock. Your browser reads the local OS time via JavaScript getTimezoneOffset, which still reports your real timezone. This creates VPN location mismatch that anti-fraud systems detect.
How to fix timezone dissonance when using a VPN 2026?
Change your system timezone to match your VPN server location. Or use anti-detect browsers like Multilogin, AdsPower, or Kameleo with automatic timezone spoofing. Tor Browser reports UTC for all users, eliminating dissonance entirely.
How do websites detect proxies via timezone dissonance?
Websites call Intl.DateTimeFormat and getTimezoneOffset in JavaScript, then compare the result against your IP's GeoIP timezone. A mismatch adds risk points to bot detection scoring. Combined with other signals, it triggers blocks or CAPTCHAs.
Can anti-detect browsers fix timezone leaks?
Yes. Multilogin, AdsPower, and Kameleo override JavaScript timezone APIs. But basic configurations may still leak via performance.timeOrigin or Date().toString(). Always verify with a timezone spoofing test.
Does Tor Browser prevent timezone dissonance?
Yes. Tor Browser reports UTC (GMT+0) as the timezone for all users worldwide. This standardization makes all Tor users look identical, completely eliminating timezone dissonance as a detection vector.
Is timezone mismatch used for bot detection?
Yes. Timezone dissonance is a high-weight signal in bot detection scoring. A >3 hour mismatch adds 40+ risk points. Combined with VPN detection and browser fingerprints, it pushes scores above fraud thresholds, triggering blocks.
What is the best free tool to check browser and system time consistency?
The TrustMyIP timezone dissonance test compares IP vs browser timezone, calculates UTC offset difference, checks DST alignment, and provides risk scoring — all free with no signup required.
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Is Your Clock Betraying Your Location?
Free IP vs Browser Timezone Check
Your system time creates a timezone dissonance signal that VPNs cannot mask. Run our free browser timezone mismatch checker to verify your proxy timezone alignment.