Lookup nearest value

zbor, that wouldn't work if D4 were say 4.1

KevinThomas, it will depend in part on how many variants of this calculation you're performing... the simplest non-array approach would be to store the ABS vaiance of A1:A26 to D4 in C1:C26 and then use a standard INDEX/MATCH as outlined by zbor

=INDEX(B1:B26,MATCH(MIN(C1:C26),C1:C26,0))

You can do this in non-array form without helpers

=INDEX(B1:B26,MATCH(MIN(INDEX(ABS(A1:A26-D4),0)),INDEX(ABS(A1:A26-D4),0),0)

but this is not efficient.