How It Works
Clockzilla uses a multi-tier NTP-style synchronization engine to measure the exact offset between your local clock and accurate reference time. Here's how the process works under the hood.
1. Multi-Source Sampling
Clockzilla sends concurrent requests to 3 time servers across different tiers. Each request records precise timestamps before and after the network round-trip.
2. RTT Measurement
For each response, we calculate the Round-Trip Time (RTT) — the total time the request took. The server's time is estimated at the midpoint: local_time + RTT/2.
3. Offset Calculation
The offset is computed as: server_time - (local_time + RTT/2). This tells us exactly how far ahead or behind your local clock is relative to the server.
4. Multiple Rounds
We repeat this process 3 times across all sources, collecting up to 9 samples total. More samples means better statistical confidence.
5. Outlier Removal
Using Median Absolute Deviation (MAD), we identify and discard samples that deviate significantly from the median. This eliminates results skewed by network congestion.
6. Weighted Average
The final offset is a weighted mean where lower-RTT samples receive more weight — because shorter round-trips produce more accurate measurements.
The result: an accurate, reliable measurement of your computer's clock drift — typically within 50-500 milliseconds of true time, depending on your network. Clockzilla then auto-resyncs every 4 minutes to keep the displayed time fresh.