Calculate new shape of conker (6)
I believe the answer is:
reckon
'calculate new shape' is the definition.
'reckon' can be an answer for 'calculate' (synonyms). I'm not sure about the 'new shape' bit.
'of conker' is the wordplay.
'of' indicates anagramming the letters (the answer comes from or \'of\' the letters).
'conker' with letters rearranged gives 'RECKON'.
Can you help me to learn more?
(Other definitions for reckon that I've seen before include "Consider or calculate" , "Calculate or conclude" , "Calculate, be of the opinion" , "Consider, judge to be probable" , "Consicer or calculate" .)