How long should headers be for an arduino shield?

[shivamhegadi]

I have a shield, and an arduino uno r4, but how long should the male headers be to connect the shield to the arduino. (stacking) I have found these: https://www.amazon.com/MCIGICM-Header-2-45mm-Arduino-Connector/dp/B07PKKY8BX/ref=sr_1_2?crid=1UEOXELICVZ9C&dib=eyJ2IjoiMSJ9.BmbJVa48sjWjwCc0F7WyYsT_UPuYt2e-Dqw7yRRquYNGFCICz8gPeA1Fj_lhD3d-QGOIBvVi7cwab8tchdPufdiY0kOsJ6g8qBskgWm5tv1ahYCHH6bVKFlurmGuZSKjRAxHLluAHDKJNgPFyYVSbcOvlziuit7D49er1zdAiGC8r--p4g5194UvqMR33YpPw-H4BL6nJeU6ZR0H5oFS_twgg8Uvx65lOyCCjnpT45Y.2sJaFv7sFSpFHK0J_eK4tu2X0dw3G8z5cBBFUd3ZweU&dib_tag=se&keywords=extra+long+male+headers+arduino&qid=1725210856&sprefix=extra+long+male+headers+arduino%2Caps%2C193&sr=8-2

[PerryBebbington]

@shivamhegadi

but how long should the male headers be to connect the shield to the arduino.

As long as you need them to be.

What is your concern?

[westfw]

Those headers should work fine.
There's a "standard" length (~6mm of bare metal?) for male headers, and that (or longer) will work fine.

You have to be more careful with "stacking" headers, since you have to allow for going through the board, a mm or two of solder, possible spacers...

[JohnLincoln]

I regularly use that type of pin headers. They work well.

@westfw

There's a "standard" length (~6mm of bare metal?)

I've just measured some, and I agree with that 6mm.

[shivamhegadi]

so it will stick into the arduino right?
thanks

[JohnLincoln]

@shivamhegadi

so it will stick into the arduino right?

Yes, and the pins go right down to the bottom of the socket on the Arduino.

[shivamhegadi]

Alright, thank you very much.

[Nick_Pyner]

The Uno USB socket is 10mm high. An ethernet socket is 12mm. Store-bought shields typically have 13mm pins. Why would you settle for anything less?

[westfw]

@Nick_Pyner

Store-bought shields typically have 13mm pins.

Most store-bought shields have stacking headers, which are missing the spacers on the bottom side...

Measuring from where to where? The full length of the "standard" headers I've described is about 11.5mm (6mm inserted pin, 2.5 to 3mm of spacer and soldered pin.) The female headers on most boards are 8mm high, and they have some "bottom" to them - much more than the 6mm length will "bottom out" and leave bare-metal pins exposed above the socket (which may or may not be desirable. Clearing the USB or Ethernet connector is good, and having a place to attach probes might be nice.
But I think that technically, assuring clearance of board components is supposed to be the job of the female connectors on the board with the high components (A bit of a fail on the original Arduinos...)

Edit: adding...
Most female sockets seem designed to mate with a pin 5mm or less in length.