Tutorial · 5 min read
How to Convert Timestamps in JSON — Smart Timestamp Detector Guide
Your JSON has timestamps — but they're in Unix milliseconds, and you need a readable date. Or they're in ISO format, and you need YYYY/MM/DD for your spreadsheet. The Smart Timestamp Detector in our JSON to CSV converter auto-detects and converts timestamps across your entire data table with one click.
1. What Is the Smart Timestamp Detector?
The Smart Timestamp Detector is a built-in feature across JSONXX tools that automatically:
- Detects timestamp columns by sampling the first 100 rows of your data
- Identifies the format — ISO 8601, Unix seconds, Unix milliseconds, RFC 2822, and more
- Converts entire columns between formats with a single click
- Preserves your original data — conversion only changes the display, not the underlying JSON
When a column is detected as containing timestamps, a red 🕐 Convert badge appears next to the column header. Click it to open the format selector menu.
2. Supported Timestamp Formats
The detector automatically recognizes these timestamp formats in your JSON data — no manual configuration needed:
| Format | Example | Type |
|---|---|---|
| Unix Seconds | 1718181000 | 10-digit number |
| Unix Milliseconds | 1718181000000 | 13-digit number |
| ISO 8601 | 2026-06-12T14:30:00Z | String with T separator and timezone |
| YYYY/MM/DD | 2026/06/12 | Date with slash separators |
| MM/DD/YYYY | 06/12/2026 | US-style date |
| DD/MM/YYYY | 12/06/2026 | European-style date |
| DD.MM.YYYY | 12.06.2026 | European dot-separated date |
| YYYYMMDD | 20260612 | Compact 8-digit date |
| RFC 2822 | Fri, 12 Jun 2026 14:30:00 GMT | Email/HTTP date format |
The detector handles ambiguous formats intelligently. For example, 06/12/2026 could be June 12 or December 6 — the detector uses value-based disambiguation to determine the correct interpretation.
3. How to Use the Timestamp Detector
Using the Smart Timestamp Detector takes just three steps:
- Paste your JSON into any JSONXX tool with table view — try it in the JSON to CSV converter.
- Look for the red 🕐 Convert badge on column headers. This tells you which columns contain timestamps.
- Click the badge to open the format menu. Choose from: Readable, Date, Slash, EU, US, or Reset to original.
The entire column converts instantly. Try different formats to find the one that works best for your use case — all without modifying your original JSON data.
4. Output Format Options — Before & After
The table below shows the full input → output mapping. Each row is a detected input format (from §2), and the columns show what it becomes in each of the 5 available output formats. All examples represent June 12, 2026, 14:30 (with time where applicable).
| Detected Format | Raw JSON Value | → Readable YYYY-MM-DD HH:MM:SS |
→ Date YYYY-MM-DD |
→ Slash YYYY/MM/DD |
→ EU DD/MM/YYYY |
→ US MM/DD/YYYY |
|---|---|---|---|---|---|---|
| Unix Seconds | 1718181000 | 2026-06-12 14:30:00 | 2026-06-12 | 2026/06/12 | 12/06/2026 | 06/12/2026 |
| Unix Milliseconds | 1718181000000 | 2026-06-12 14:30:00 | 2026-06-12 | 2026/06/12 | 12/06/2026 | 06/12/2026 |
| ISO 8601 | 2026-06-12T14:30:00Z | 2026-06-12 14:30:00 | 2026-06-12 | 2026/06/12 | 12/06/2026 | 06/12/2026 |
| YYYY/MM/DD | 2026/06/12 | 2026-06-12 00:00:00 | 2026-06-12 | 2026/06/12 | 12/06/2026 | 06/12/2026 |
| MM/DD/YYYY | 06/12/2026 | 2026-06-12 00:00:00 | 2026-06-12 | 2026/06/12 | 12/06/2026 | 06/12/2026 |
| DD/MM/YYYY | 12/06/2026 | 2026-06-12 00:00:00 | 2026-06-12 | 2026/06/12 | 12/06/2026 | 06/12/2026 |
| DD.MM.YYYY | 12.06.2026 | 2026-06-12 00:00:00 | 2026-06-12 | 2026/06/12 | 12/06/2026 | 06/12/2026 |
| YYYYMMDD | 20260612 | 2026-06-12 00:00:00 | 2026-06-12 | 2026/06/12 | 12/06/2026 | 06/12/2026 |
| RFC 2822 | Fri, 12 Jun 2026 14:30:00 GMT | 2026-06-12 14:30:00 | 2026-06-12 | 2026/06/12 | 12/06/2026 | 06/12/2026 |
Note: Inputs with time information (Unix, ISO, RFC) preserve time in the output as 14:30:00. Date-only inputs (slash, dot, compact) default to 00:00:00 since no time component exists in the original value.
5. Best Practices for Timestamp Conversion
- Check a few rows before converting. The detector samples 100 rows. If your dataset has mixed formats (e.g., most rows use Unix seconds but a few use ISO), verify the detection is consistent.
- Use Readable or Date format for exports. When preparing data for sharing with non-technical stakeholders, Readable format (YYYY-MM-DD HH:MM:SS) makes the spreadsheet immediately understandable.
- Use Slash format for database exports. The YYYY/MM/DD format is widely compatible with SQL databases and spreadsheet imports without date parsing issues.
- Use Excel for timezone-sensitive data. When exporting to spreadsheets, the JSON to Excel converter preserves date types properly. See our guide to JSON to Excel without losing formatting for details.
- Reset before re-converting. If you want to try a different output format, click "Reset to original" first to restore the detected original format, then choose a new one.
Try the Smart Timestamp Detector
Paste JSON with timestamps and see the Smart Timestamp Detector in action. Convert entire columns between formats with one click.
Try Timestamp Detection Now →Frequently Asked Questions
What timestamp formats does the Smart Timestamp Detector support?
It supports ISO 8601, Unix seconds (epoch), Unix milliseconds, RFC 2822, YYYY/MM/DD, DD.MM.YYYY, and YYYYMMDD. Detection is automatic — no configuration needed.
How does it distinguish Unix seconds from Unix milliseconds?
The detector analyzes the number magnitude. Values around 1.5-1.8 billion (current epoch range) are treated as seconds. Values 1000x larger (trillions) are treated as milliseconds.
Does converting timestamps modify my original JSON data?
No. The conversion only changes how values are displayed in the table. The original JSON data remains untouched. Use "Reset to original" to revert any column.
What output formats can I convert to?
Readable (e.g., "2026-06-12 14:30:00"), Date-only (YYYY-MM-DD), Slash (YYYY/MM/DD), EU (DD/MM/YYYY), and US (MM/DD/YYYY). Plus a "Reset to original" option to restore the detected format.
Which JSONXX tools have the Smart Timestamp Detector?
JSON to CSV, JSON to Excel, JSON to Markdown, JSON to Table, and JSON Editor. Any tool with a table view gets detection and conversion capabilities automatically.
Looking for more guides? See the full JSONXX How To index.