{"format":"ptob-page","version":1,"canonical":"https://ptob.dev/time/","title":"Precision time — PToB","description":"UTC, local time and Unix timestamps, with a device clock comparison and its estimated uncertainty.","language":"en","robots":"noindex, nofollow","authors":["Jonathan Yantis"],"representations":{"application/json":"https://ptob.dev/time/?format=json","text/markdown":"https://ptob.dev/time/?format=markdown"},"documentation":"https://ptob.dev/agent-formats.json","social":{"openGraph":{"title":"Precision time — PToB","description":"UTC, local time and Unix timestamps, with a device clock comparison and its estimated uncertainty.","url":"https://ptob.dev/time/","type":"website","siteName":"PToB","locale":"en_US","image":{"url":"https://ptob.dev/social/ptob-timing-v3.jpg","secureUrl":"https://ptob.dev/social/ptob-timing-v3.jpg","type":"image/jpeg","width":"1200","height":"630","alt":"PToB: nanosecond time sync over Bluetooth. T096: 62.5 ns one-relay PPS-shadow RMS. W12 ESP32-S3: 60.3 ns relative-PPS RMS; 522/600 eligible, max 180 ns."}},"twitter":{"card":"summary_large_image","title":"Precision time — PToB","description":"UTC, local time and Unix timestamps, with a device clock comparison and its estimated uncertainty.","image":{"url":"https://ptob.dev/social/ptob-timing-v3.jpg","alt":"PToB: nanosecond time sync over Bluetooth. T096: 62.5 ns one-relay PPS-shadow RMS. W12 ESP32-S3: 60.3 ns relative-PPS RMS; 522/600 eligible, max 180 ns."}}},"citations":[],"provenance":{"sourceUrl":"https://ptob.dev/time/","sourceMediaType":"text/html","sourceSha256":"8c58216db92da1eabc571971a7127ca84a9250b3526dc577e6ffe9de20ba3ad8"},"contentUsage":{"aiTrain":true,"search":true,"aiInput":true,"reason":"summary-or-introduction"},"structuredData":[{"@context":"https://schema.org","@graph":[{"@type":"WebSite","@id":"https://ptob.dev/#website","url":"https://ptob.dev/","name":"PToB","alternateName":["Precision Time over BLE","Precision Time over Bluetooth"],"description":"Bluetooth and USB software clocks: W12 60.3 ns relative-PPS RMS over 522/600 observations, separate 64 s sampled holdover, and CoreSE diagnostics.","inLanguage":["en","de"],"publisher":{"@id":"https://ptob.dev/#jonathan-yantis"}},{"@type":"Person","@id":"https://ptob.dev/#jonathan-yantis","name":"Jonathan Yantis","url":"https://github.com/yantisj2/PToB/blob/main/CREDITS.md"},{"@type":"Project","@id":"https://ptob.dev/#project","name":"PToB","alternateName":"Precision Time over BLE","url":"https://ptob.dev/","description":"An independent protocol project researching precision time transfer across Bluetooth-enabled microcontrollers and USB clients.","sameAs":"https://github.com/yantisj2/PToB","member":{"@id":"https://ptob.dev/#jonathan-yantis"},"knowsAbout":{"@id":"https://ptob.dev/#protocol"}},{"@type":"Thing","@id":"https://ptob.dev/#protocol","name":"Precision Time over BLE","alternateName":"PToB","description":"An experimental PTP-inspired protocol proposal for wireless clock synchronization over Bluetooth Low Energy."},{"@type":"WebPage","@id":"https://ptob.dev/time/#webpage","url":"https://ptob.dev/time/","name":"Precision time — PToB","description":"UTC, local time and Unix timestamps, with a device clock comparison and its estimated uncertainty.","inLanguage":"en","keywords":["Precision Time over BLE","sub-1us time transfer over Bluetooth","sub-1us time transfer over USB","Experimental LoRa time transfer","MCU clock synchronization","Software PLL between heterogeneous devices","Boundary-clock relays"],"isPartOf":{"@id":"https://ptob.dev/#website"},"author":{"@id":"https://ptob.dev/#jonathan-yantis"},"about":{"@id":"https://ptob.dev/#protocol"},"image":"https://ptob.dev/social/ptob-timing-v3.jpg","breadcrumb":{"@id":"https://ptob.dev/time/#breadcrumbs"}},{"@type":"BreadcrumbList","@id":"https://ptob.dev/time/#breadcrumbs","itemListElement":[{"@type":"ListItem","position":1,"name":"PToB","item":"https://ptob.dev/"},{"@type":"ListItem","position":2,"name":"Precision time — PToB","item":"https://ptob.dev/time/"}]}]}],"content":{"mediaType":"text/markdown","headings":[{"level":1,"text":"Precision time","url":"https://ptob.dev/time/#time-title"},{"level":2,"text":"Time coordinates","url":"https://ptob.dev/time/#main"},{"level":2,"text":"Your location","url":"https://ptob.dev/time/#main"},{"level":2,"text":"How this works","url":"https://ptob.dev/time/#main"}],"links":[{"text":"Cloudflare NTP reference","url":"https://developers.cloudflare.com/time-services/ntp/"},{"text":"ipwho.is","url":"https://ipwhois.io/privacy"}],"text":"# Precision time\n\n Acquiring reference\n\nUTC   —:—:—  .—\n\nWaiting for reference\n\nLocal time   —:—:—  .—\n\nWaiting for reference\n\nUnix timestamp  seconds\n\n—\n\nISO 8601  UTC\n\n—\n\nYour device · local    —:—:—  .—\n\nChecking your clock…\n\nStarting the clock check…\n\nClock offset\n\n—\n\nUncertainty\n\n—\n\nRound trip\n\n—\n\nSamples\n\n—\n\n## Time coordinates\n\nLocal time zone\n\n—\n\nUTC offset\n\n—\n\nDay of year · UTC\n\n—\n\nISO week · UTC\n\n—\n\n## Your location\n\nFinding your approximate city…\n\nCity is estimated from your IP address. VPNs and mobile networks can place you elsewhere. Local time follows your browser’s time zone.\n\n## How this works\n\nSeven HTTPS requests compare your device clock with our server’s recent [Cloudflare NTP reference](https://developers.cloudflare.com/time-services/ntp/). The consistent sample with the lowest estimated uncertainty supplies the result.\n\nAccuracy and privacy\n\nClock offset is your device time minus the reference: positive means ahead, negative means behind. The uncertainty includes network travel, the NTP reference’s reported uncertainty and an allowance for reference age and browser timers.\n\nThe estimate assumes roughly equal travel time in both directions. Unequal routes, browser scheduling and timer rounding can add error. This is an internet clock check, not a precision calibration. Plain NTP is not cryptographically authenticated.\n\nUTC, local time, the analog dial and timestamps represent the same estimated instant. The dial uses a 12-hour UTC face, with tenths of a second on the small dial at 9 o’clock. The 24-hour digital clocks show tenths of a second. Unix timestamps count whole seconds since 1 January 1970 UTC, excluding leap seconds.\n\nThis page reads your clock; it does not set it. After the seven-sample check, readouts advance locally without polling. After one minute they are labeled as a local estimate and the comparison expires. Use Check again for a fresh measurement. Returning to the tab or changing the device clock also starts a fresh check.\n\nApproximate city detection uses [ipwho.is](https://ipwhois.io/privacy), which receives your IP address when this page opens. PToB does not store your location or test results."}}