Component Date Code Decoder
Turn a 4-digit YYWW / WWYY date code into a year, ISO week, and date range.
What it does: Decode the 4-digit date code stamped on a part into the year and the calendar week it was made.
When to use it: When you find a YYWW (or WWYY) code on an IC, capacitor, or connector and want to know how old it is.
Enter the 4 digits printed on the part and pick the format. The result uses the ISO week? numbering scheme.
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No history yet. Each calculation is automatically saved to this device.
How to decode a date code
Type the 4 digits → pick the format → read the decoded week.
- 01
Type the 4-digit code
Enter the 4 digits printed on the part, e.g. 2334. Lot/batch codes are different — this tool decodes a year + week date code only.
- 02
Pick the format
Choose YYWW (year first, the most common) or WWYY (week first). Formats vary by manufacturer, so match what the datasheet says.
- 03
Read the decoded week
You get the calendar year, the ISO week number, and the exact Monday–Sunday date range that week covers.
Example codes
How a few sample 4-digit codes decode under each format.
| Code | Format | Decodes to |
|---|---|---|
| 2334 | YYWW | Year 2023, week 34 (2023-08-21 → 2023-08-27) |
| 0801 | YYWW | Year 2008, week 1 (2007-12-31 → 2008-01-06) |
| 3423 | WWYY | Week 34, year 2023 (2023-08-21 → 2023-08-27) |
| 1052 | YYWW | Year 2010, week 52 |
Decoded with the ISO-8601 week algorithm (Jan 4 is always in week 1).
Common questions, answered in 3 minutes
Do date-code formats really vary by manufacturer?
Yes. There is no single universal standard for the marking. YYWW (year then week) is the most common, but some vendors print WWYY, and a few use date codes that are not a year+week scheme at all. Always confirm against the manufacturer's datasheet.
Is my code YYWW or WWYY?
Use the toggle to try both and see which range is plausible. A quick rule of thumb: the week half is 01–53, so if one pair of digits is > 53 it must be the year. When in doubt, the datasheet or the part's known production era settles it.
What is an ISO week?
ISO-8601 defines weeks that always start on Monday, and week 1 is the week containing January 4 (equivalently, the year's first Thursday). This is why early-January codes can fall in the last days of the previous calendar year.
Could the YY mean 19xx instead of 20xx?
Possibly. A 2-digit year is ambiguous. This tool assumes 20xx, but for older components the same digits could mean 19xx — the result note points this out. The manufacturer or the part's vintage is authoritative.
Standards and sources referenced by this tool
| Item | Value / Formula | Source |
|---|---|---|
| Week numbering | ISO-8601 (Jan 4 in week 1) | ISO 8601 |
| Date-code format | YYWW / WWYY (varies by vendor) | Manufacturer datasheet |
This assumes a YYWW/WWYY year+week date code; lot/batch codes use other schemes and are not handled here. Treat the manufacturer / datasheet as authoritative.