The workload is similar,
depending on where you go.
I have seen some double degrees that do 5 subjects per semester rather than the standard 4 for a full time load. One subject extra per semester.... that often is one subject too many depending on whether you can handle it.
Would I say do it... most certainly if you can handle it. Two degrees are better than one, keeping in mind you will be paying for both
And the best part is, you can (most of the time) transfer to just a single degree if you feel the workload is too much and unbearable.
I would be weighing up whether doing a double degree is beneficial for your future aspirations. Will both degrees contribute to your future success or will only one? What are the benefits of doing a double degree with two bachelors rather than a bachelor + master combination? Just putting some things out there for consideration. It will be entirely dependent on your circumstances.
Usually you can find course handbooks/maps on the university website (or google, most are indexed). These outline the subjects you have to do. I'd take a look at them as a first point of reference.