Voltage regulation is the difference between no load voltage and full load voltage by no load voltage.
Voltage regulation = No load voltage – Full load voltage / No load voltage.
Voltage regulation is mentioned in % (percentage).
% Voltage regulation = No load voltage – Full load voltage * 100 / No load voltage.
Efficiency of a transformer is the ratio of output in watts and input in watts.
Efficiency = Output in watts / Input in watts.
% Efficiency = Output in watts * 100 / Input in watts.
% Efficiency = Output in watts * 100 / Output in watts + losses.