The all-in total (5)
I believe the answer is:
tally
'the all-in total' is the definition.
'tally' can be an answer for 'total' (thesaurus). I'm not sure about the 'the all-in' bit.
'all-in total' is the wordplay.
'in' indicates putting letters inside.
'total' becomes 'ty' (I can't explain this - if you can you should give a lot more credence to this answer).
'all' put into 'ty' is 'TALLY'.
Can you help me to learn more?
(Other definitions for tally that I've seen before include "Match - score" , "List" , "Current score; agree" , "Record; agree" , "Mark" .)