# Molex Micro-Fit 3.0, Mini-Fit Jr. and KK 254: pitch 3.00 / 4.20 / 2.54 mm, PC tail, mated height, Mini-Fit header dimensions by circuit count

> What is the pitch of Molex Micro-Fit, Mini-Fit Jr. and KK 254 connectors, and how wide is the header for n circuits?

- Category: Electronic components › Connectors
- Kind: Standard part
- Basis: Molex part sheets (copies hosted by e-sonic, Chipdip, RS, datasheet.su, datasheets.com and IBS); molex.com itself could not be fetched, so the sales drawings are not read; numbers only
- Page: https://xemstudio.com/objects/molex-micro-fit-mini-fit-kk-254-pitch/ · JSON: https://xemstudio.com/api/geometry?object=molex-micro-fit-mini-fit-kk-254-pitch · Plain text: https://xemstudio.com/objects/molex-micro-fit-mini-fit-kk-254-pitch/sheet.txt
- License: dimension sheet CC BY 4.0 (Xem Studio); files CC BY 4.0 or their publisher's license
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**Exact dimensions.** True size, with no tolerance added.

## Notes

- Pitch: Micro-Fit 3.0 is 3.00 mm, Mini-Fit Jr. 4.20 mm (.165 in) and KK 254 2.54 mm (.100 in). The part sheets also print PC tail lengths, mated heights and recommended PCB thickness (1.60 mm), shown in the rows above.
- Housing width by circuit count: the Mini-Fit Jr. header sheet (39-29-9087) prints three values per circuit count under 'Dimension ABC' for 2 to 24 circuits, shown as printed. Arithmetic on those printed numbers, not a published formula: the first value equals 1.20 + 4.20 x (circuits / 2) mm on all 12 rows, the second equals the first minus 5.40 (the 2-circuit row has none) and the third the first plus 4.00. The text read does not say what A, B and C measure.
- Not published in anything read: housing width formulas for Micro-Fit and KK, PCB hole diameters and board footprints. Those are in the Molex sales drawings (SD-43045-010, SD-43045-006, SD-4030-0001-001, SD-6373-001-002) and Molex symbol / footprint files (SYM-43045-0627), which could not be fetched. The Molex sheets cite them; use them for a board layout. No files for that reason.
- The KK 254 header on the 6410 sheet is a friction-lock header (2 to 28 circuits); the 7478 right-angle header is a different series (22-05- tin, 22-12- gold). The JST and 2.54 mm pin-header pages are separate: jst-connectors, pin-headers-2.54mm.
- Maker CAD: Molex publishes STEP per part on molex.com; not linked here because the site was not reachable while reading.

## Sizes

| series | item | value | unit / note | source |
|---|---|---|---|---|
| Micro-Fit 3.0 (43045 headers) | pitch, mating interface | 3.00 | mm; dual row | Molex 43045 sheets |
| Micro-Fit 3.0 vertical header | mated height | 17.64 | mm | Molex 0430450629, 0430450215 |
| Micro-Fit 3.0 right-angle header | mated height | 10.06 | mm (press-fit 2-circuit part) | Molex 0430450223 |
| Micro-Fit 3.0 vertical header 43045-0629 | PC tail length / recommended PCB thickness | 3.18 / 1.60 | mm | Molex 0430450629 sheet |
| Micro-Fit 3.0 vertical press-fit header | rating on the sheet | 5.0 A max per contact, 600 V | Misumi's page for the 43045 family prints 8.5 A and 5.0 A (not used) | Molex 0430450215 sheet |
| Micro-Fit 3.0 single row (43645) | pitch / rows / circuits max | 3.00 / 1 / 4 | mm | Molex 43645-0400 |
| Mini-Fit Jr. (5557 housings) | pitch, mating and termination interface | 4.20 (.165 in) | mm; dual row; 39-01-2080 is 8 circuits | Molex 0039012080 |
| KK 254 (6410 vertical header, 22-27-xxx1) | pitch / PC tail length / contact | 2.54 (.100 in) / 3.56 / 0.64 square | mm; brass contact; 4.0 A, 250 V; 2 to 28 circuits ordered as 22-27-2021 to 22-27-2281 | Molex 22-27-2021 sheet |
| KK 254 header (8 circuits, SD-4030-0001-001) | pitch / PC tail / PCB thickness | 2.54 / 3.43 / 1.60 | mm | Molex sheet via Chipdip |
| KK 254 right-angle header (022124022) | pitch / PC tail / PCB thickness | 2.54 / 3.80 / 1.60 | mm | Molex sheet via RS |
| Mini-Fit Jr. header ordering table (39-29-9087 sheet) | 2 circuits: 'Dimension ABC' first / second / third | 5.40 / — / 9.40 | mm, as printed; the text read does not say which letter is which | Molex 39-29-9087 sheet |
| Mini-Fit Jr. header ordering table (39-29-9087 sheet) | 4 circuits: 'Dimension ABC' first / second / third | 9.60 / 4.20 / 13.60 | mm, as printed; the text read does not say which letter is which | Molex 39-29-9087 sheet |
| Mini-Fit Jr. header ordering table (39-29-9087 sheet) | 6 circuits: 'Dimension ABC' first / second / third | 13.80 / 8.40 / 17.80 | mm, as printed; the text read does not say which letter is which | Molex 39-29-9087 sheet |
| Mini-Fit Jr. header ordering table (39-29-9087 sheet) | 8 circuits: 'Dimension ABC' first / second / third | 18.00 / 12.60 / 22.00 | mm, as printed; the text read does not say which letter is which | Molex 39-29-9087 sheet |
| Mini-Fit Jr. header ordering table (39-29-9087 sheet) | 10 circuits: 'Dimension ABC' first / second / third | 22.20 / 16.80 / 26.20 | mm, as printed; the text read does not say which letter is which | Molex 39-29-9087 sheet |
| Mini-Fit Jr. header ordering table (39-29-9087 sheet) | 12 circuits: 'Dimension ABC' first / second / third | 26.40 / 21.00 / 30.40 | mm, as printed; the text read does not say which letter is which | Molex 39-29-9087 sheet |
| Mini-Fit Jr. header ordering table (39-29-9087 sheet) | 14 circuits: 'Dimension ABC' first / second / third | 30.60 / 25.20 / 34.60 | mm, as printed; the text read does not say which letter is which | Molex 39-29-9087 sheet |
| Mini-Fit Jr. header ordering table (39-29-9087 sheet) | 16 circuits: 'Dimension ABC' first / second / third | 34.80 / 29.40 / 38.80 | mm, as printed; the text read does not say which letter is which | Molex 39-29-9087 sheet |
| Mini-Fit Jr. header ordering table (39-29-9087 sheet) | 18 circuits: 'Dimension ABC' first / second / third | 39.00 / 33.60 / 43.00 | mm, as printed; the text read does not say which letter is which | Molex 39-29-9087 sheet |
| Mini-Fit Jr. header ordering table (39-29-9087 sheet) | 20 circuits: 'Dimension ABC' first / second / third | 43.20 / 37.80 / 47.20 | mm, as printed; the text read does not say which letter is which | Molex 39-29-9087 sheet |
| Mini-Fit Jr. header ordering table (39-29-9087 sheet) | 22 circuits: 'Dimension ABC' first / second / third | 47.40 / 42.00 / 51.40 | mm, as printed; the text read does not say which letter is which | Molex 39-29-9087 sheet |
| Mini-Fit Jr. header ordering table (39-29-9087 sheet) | 24 circuits: 'Dimension ABC' first / second / third | 51.60 / 46.20 / 55.60 | mm, as printed; the text read does not say which letter is which | Molex 39-29-9087 sheet |

## Where the files are

- Molex (e-sonic copy of 0430450629 sheet): [Micro-Fit 3.0 vertical header 43045-0629, 6 circuits, dual row: pitch 3.00 mm, mated height 17.64 mm, PC tail 3.18 mm, PCB 1.60 mm](https://www.e-sonic.com/productfiles/mf-mol/0430450629_pcb_headers.pdf) — web — Publisher's page; dimensions are facts
- Molex (Chipdip copy of 0430450215 sheet): [Micro-Fit 3.0 vertical header, 2 circuits, press-fit: 5.0 A, 600 V, mated height 17.64 mm](https://static.chipdip.ru/lib/759/DOC031759394.pdf) — web — Publisher's page; dimensions are facts
- Molex (RS copy of 0430450223 sheet): [Micro-Fit 3.0 right-angle header, 2 circuits, press-fit: mated height 10.06 mm](https://docs.rs-online.com/fd61/A700000014857160.pdf) — web — Publisher's page; dimensions are facts
- Misumi: [Micro-Fit 3.0 43045 family page: pitch 3.00 mm, PCB 1.60 mm, mated heights; prints both 8.5 A and 5.0 A](https://my.misumi-ec.com/vona2/detail/222000610070/) — web — Publisher's page; dimensions are facts
- Molex (IBS copy of 43645-0400 sheet): [Micro-Fit 3.0 single-row 43645: pitch 3.00 mm, 4 circuits maximum](https://datasheets.ibselectronics.com/43645-0400-Molex-datasheet-140450946.pdf) — web — Publisher's page; dimensions are facts
- Molex (datasheet.su copy of 39-01-2080): [Mini-Fit Jr. 5557 receptacle housing 0039012080, 8 circuits: pitch 4.20 mm (.165 in)](https://pdf2.datasheet.su/molex/39-01-2080.pdf) — web — Publisher's page; dimensions are facts
- Molex (datasheets.com copy of 39-29-9087 sheet): [Mini-Fit Jr. header ordering table: 'Dimension ABC' for 2 to 24 circuits, with and without drain holes](https://static.datasheets.com/doc/7701787-molex-39-29-9087-ds.pdf) — web — Publisher's page; dimensions are facts
- Molex (datasheet.su copy of 22-27-2021): [KK 254 6410 series vertical header with friction lock, 22-27-2021 (2 circuits) to 28 circuits: pitch 2.54 mm, PC tail 3.56 mm, 0.64 mm square contact, 4.0 A, 250 V](https://pdf2.datasheet.su/molex/22-27-2021.pdf) — web — Publisher's page; dimensions are facts
- Molex (Chipdip copy, 8-circuit KK header, SD-4030-0001-001): [KK 254 header, 8 circuits: pitch 2.54 mm, PC tail 3.43 mm, PCB 1.60 mm](https://static.chipdip.ru/lib/741/DOC011741313.pdf) — web — Publisher's page; dimensions are facts
- Molex (RS copy, 022124022 right-angle KK header): [KK 254 right-angle header, 2 circuits: pitch 2.54 mm, PC tail 3.80 mm, PCB 1.60 mm](https://docs.rs-online.com/e937/A700000015397410.pdf) — web — Publisher's page; dimensions are facts

## Questions

**What is the pitch of Mini-Fit Jr.?**

4.20 mm (.165 in), dual row (Molex 5557 housing sheet).

**What is the pitch of Micro-Fit 3.0?**

3.00 mm for the 43045 dual-row headers and the single-row 43645; vertical headers mate at 17.64 mm, right-angle at 10.06 mm.

**How wide is an 8-circuit Mini-Fit Jr. header?**

The 39-29-9087 sheet prints 18.00, 12.60 and 22.00 mm under 'Dimension ABC' for 8 circuits; it does not label which is the body width.

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