pound-for-pound

(not comparable)A comparison of fighters' (usually boxers) skill levels, regardless of what weight class they are in.

Sugar Ray Robinson is pound for pound the best boxer ever.

(not comparable)Pertaining to how any two things compare when bearing in mind their real or relative, figurative weight.

A tin of tomatoes weighing 250 g and costing $2.50 is more expensive, pound-for-pound, than one weighing 500 g and costing $4 (as the former costs $1.00 per 100 g and the latter $0.80 per 100 g).

My gal is pound for pound sweeter than chocolate.