Can i make an exact copy of my laptops drive onto an external, in case I ever want to make a clean install?

I have windows 8.1 as a default installed on my lenovo yoga 3 pro. I also have a large external hdd, and i just got a new larger ssd to use on my laptop (i will sell the one that came with it). I plan on installing ubuntu when i install the new SSD, but I'd like to copy the original partitions onto my external in a way that if i so chose, I could repartition my new ssd to dual boot windows and ubuntu, or at least reinstall windows from whatever I can copy onto my external drive.

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