How to calculate group delay and compensate it by zero padding?

The filtered signal has a time shift. How can ı measure the group delay of the filter?

fs = 5000;

tiv=1/fs;

t = 0:tiv:0.05;

t1=2*pi*100*t;

t2=2*pi*500*t;

x = sin(t1)+0.7*cos(t2);

xn = x + 5.*randn(size(t));

d = designfilt('lowpassfir', 'PassbandFrequency', 500, ...

'StopbandFrequency', 600, ...

'PassbandRipple', 1, 'StopbandAttenuation', 100, ...

'SampleRate', fs);

y=filter(d,xn);

subplot(2,1,1);

plot(x); hold on; plot(y);