How to Calculate Velocity

Hello All, I’m currently confused at how velocity is calculated and if my team is doing it correctly, because it feels inherently wrong.

Right now we have 4 different levels of complexity: 2 – Basic 3 – Somewhat basic 5 – Somewhat complex 8 – Complex

So our velocity is being based off of those numbers. My question is, is that correct? It seems wrong to communicate effort based off complexity. We’ve had user stories come in that take a week because of the tedium of the request, but reflect a 2.

Before we switched to complexity based, we were doing effort-base by a power of 4. 1 = 1 – 4 hours of work 2 = 2 – 8 hours of work

This had its own issues.

Any insight would be appreciated.