How old is my Surface Pro 3?

You can check your warranty status @ https://support.microsoft.com/en-us/devices

To know the age, look for the sticker on your computer having the lot number. If your lot number is 1631, it means it was made in 31st week of 2016.

ok thanks for your help, I will check that, fingers crossed.

If not then I will just have to guess I suppose.

I bought it from new but cannot find the receipt.

It was around the time the Pro 4 came out if I remember because I opted for the 3 instead as didn't feel the 4 had enough differences to justify the price difference.

Thanks again.

Thank you.

I checked the unit and no stickers, lots of moulded in samps but nothing that shows a number like that?

Authentic & foolproof information will be provided by lot number only. However, there are some ways to determine this but will not be 100% accurate

You can check for original installation date for Windows (assuming it was not reinstalled after Surface was shipped)

Right click on Windows Start > Windows Powershell (Admin) > Type following and Enter

systeminfo

Now check Original Installation Date. This is generally 10th line from top in the output which you get.

If you had reinstall Windows, then you can look for Bios version in the above output which has date also. You computer is generally few months to 1 year + this BIOS date (This is just an approximation)