Just use cov. From the help of the cov-function:
cov Covariance matrix.
cov(X), if X is a vector, returns the variance. For matrices, where
each row is an observation, and each column a variable, cov(X) is the
covariance matrix. DIAG(cov(X)) is a vector of variances for each
column, and SQRT(DIAG(cov(X))) is a vector of standard deviations.
cov(X,Y), where X and Y are matrices with the same number of elements,
is equivalent to cov([X(:) Y(:)]).
So just extract your [ n_obs x 5 ] data from your excell-file and send that matrix to the cov-function.