タイムスタンプ変換器
時間と日付 · 無料オンラインツール
Unix タイムスタンプと日付の相互変換。
Current Unix Timestamp
—
Timestamp → Date
Date → Timestamp
タイムスタンプ変換器の使い方
- 1Enter the time, date, or value you want to convert.
- 2Select the target format or timezone.
- 3The tool calculates the result instantly.
- 4Copy the converted value for your use.
機能と特徴
- ✓完全無料 — 登録不要、サブスクリプションなし、広告なし
- ✓ブラウザ上で完全に動作 — データは端末から送信されません
- ✓高速・軽量 — 即座に結果を表示
- ✓クロスプラットフォーム — デスクトップ・タブレット・モバイル対応
タイムスタンプ変換器とは？
A Unix timestamp is the number of seconds (or milliseconds) elapsed since the Unix epoch: 1970-01-01 00:00:00 UTC, excluding leap seconds. Defined by POSIX.1, it is the standard time representation in Unix systems, databases, and APIs. Timestamps are timezone-independent (always UTC).
タイムスタンプ変換器の仕組み
The converter parses timestamps (seconds or milliseconds) and creates a JavaScript Date object. The Date is displayed in UTC and the user's local timezone. Reverse conversion takes a date string, parses it, and computes (date.getTime() - epoch) / 1000.
よくある使用例
- ✓API parameters — pass time as integer to avoid timezone ambiguity
- ✓Database storage — store timestamps for consistent ordering
- ✓Cache expiry — compute TTL in seconds
- ✓Log analysis — correlate events across timezones
Unix Timestamp vs ISO 8601
Timestamps are compact integers, ideal for storage and computation. ISO 8601 strings (e.g., 2024-01-15T10:30:00Z) are human-readable and self-describing (includes timezone). Use timestamps for internal storage and computation; use ISO 8601 for API responses and human display. Most databases support both.
セキュリティとプライバシー
This tool runs entirely in your browser. Timestamps themselves have no security concerns, but be aware of the Y2038 problem: 32-bit signed integer timestamps overflow on 2038-01-19 03:14:07 UTC. Use 64-bit integers (bigint) for future-proofing.
技術的な詳細
Epoch: 1970-01-01 00:00:00 UTC (POSIX.1). Seconds: 10-digit (until 2286). Milliseconds: 13-digit (JavaScript Date.getTime()). Y2038 limit: 2147483647 (2^31-1) on 32-bit systems. Leap seconds: NOT counted in Unix time. JavaScript Date range: ±8,640,000,000,000,000 ms (±275,760 years). ISO 8601 format: YYYY-MM-DDTHH:mm:ss.sssZ.
よくある質問
What is the Y2038 problem?
32-bit signed Unix timestamps overflow on 2038-01-19 03:14:07 UTC. Systems using 32-bit time_t will break. Most 64-bit systems are unaffected. Use 64-bit integers to be safe.
Does Unix time include leap seconds?
No. POSIX.1 defines Unix time without leap seconds. Each day is exactly 86400 seconds. Leap seconds are handled by smear or repeated seconds at the application level.
Seconds or milliseconds?
Unix systems traditionally use seconds. JavaScript, Java, and most web APIs use milliseconds. 13-digit = milliseconds; 10-digit = seconds. Always check your API documentation.
関連ツール
概念を学ぶ
概念を学ぶ
このツールの背後にあるプログラミングの概念を理解します。