How do I test if my NTP synchronization is working?

Use this NTP Tester to compare your system clock against a Stratum 1 GNSS reference. An offset below 100ms indicates good synchronization. For CLI testing, run 'chronyc tracking' (Linux) or 'w32tm /query /status' (Windows).

What is an acceptable NTP clock offset?

For most systems, an offset under 100ms is excellent. Enterprise environments (Active Directory, financial systems) typically require under 50ms. Stratum 1 servers achieve sub-millisecond accuracy.

Why does my system show a large NTP offset?

Common causes include: NTP daemon not running, firewall blocking UDP port 123, no NTP servers configured, or network latency issues. Check your NTP service status and firewall rules first.

NTP Synchronization Tester | Live Clock Offset & Latency Check

Real-Time Synchronization Test

Testing your system...

🖥️ Your System

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Local Time

🌐 NTP Reference

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Server Time

✓ Excellent Synchronization

Offset: 0ms | Latency: --ms

Why Test Your NTP?

🔍 Detect Clock Skew

Identify time drift before it causes system issues or authentication failures.

⚡ Measure Latency

See how network delays affect your time synchronization accuracy.

🛠️ Troubleshoot Issues

Diagnose NTP timeouts, firewall blocks, and configuration problems instantly.

✅ Verify Sync Status

Confirm your system is properly synchronized with reliable NTP servers.

High-Precision NTP for Production

Eliminate network jitter and improve sync accuracy with our European Stratum 1 & 2 infrastructure.

Deploy Reliable NTP with RDEM Systems →

Operated over AS206014 for optimal routing

Is Your NTP Secure?

Classic NTP has zero authentication. NTS (Network Time Security) fixes that with TLS 1.3 cryptographic protection.

Learn About NTS →

Related tools — Validate NTP servers with online-ntp-validator.com · Quick diagnostic at check-ntp.net

Our infrastructure services — Beyond time synchronization, RDEM Systems also provides sauvegarde externalisée en datacenter français for business-critical data protection.

About ntp-tester.eu — A free NTP testing platform maintained by RDEM Systems. Tests run from our own AS206014 infrastructure, with time references secured via NTS and synchronized to Stratum 1 GNSS sources. Hosted on Proxmox VE clusters.
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