Do I class this as moderate or vigorous cycling?

I'm quite new to cycling so am unsure. I tend to use my stationary bike for around 40-45 minutes daily, at about 25-27.5mph, I try to go as fast as I can, so the monitor says 16 miles in 40 minutes by the time I'm done. However, I do this at a low resistance (level 3 out 8, with 8 being the highest resistance). On calorie burn calculators, do I say this is moderate or vigorous? I do get all red and sweaty at the end so I'm stuck in between moderate or vigorous.