Laptop switching off at 50% battery, then 70% and now at full battery

[MD2021]

Thank you for all your help.  I appreciate the tyre example to illustrate but I'm a bit shocked that the battery is considered defunct at 61%.  What I'm finding is that as soon as the power cord is pulled out the laptop turns off, instantly with no warning.  Shouldn't it at least power it for a few minutes?  This is my first laptop and I really am shocked that the battery is a consumable with such a short life.

[Huffer · Accepted solution]

Over 3 years is not a short life.  

https://www.google.com/search?q=average+lifespan+of+laptop+battery&rlz=1C1CHBF_enUS926US926&oq=avera...

[MD2021]

Thanks for your help.  It is only just coming up on 3 years and I still think a battery that is defunct at 61% of life is wrong but it is what it is and I guess I'll have to buy a new one.

I really appreciate your time and help though.  Thank you.