These are the doses I need to get high off of opiates. I don't know whether or not that means the doses are equivalent to each other in terms of potency, but from my own personal experience these doses are a rough conversion in terms of potency. The intensity of the effects also fluctuates a lot for me, because my weight, diet, and hours of sleep vary so drastically from one month to another. For example, I might need 45mg of hydrocodone to get high without tolerance, but then a month later I'll only need 30mg or even less to get desired effects. Anyways, here are the doses which should help give you an idea regarding tramadol's potency:
30mg Oxycodone (oral)
30-45mg Hydrocodone (oral)
30mg Methadone (oral)
250mg Tramadol
It's also worth noting that the first 4-5 times I used tramadol, I felt NOTHING, and I was taking 200mg. Then, about 4 years later, I gave it another shot and tried 250mg which gave me very decent effects. Ever since then, the intensity of tramadol's effects has been increasing every time I use it. Now, 250mg produces a fairly intense opiate high.
It also seems like I can feel tramadol's serotonergic and noradrenergic activity, as the hypomania induced in the 30 hours following a dose of tramadol is very remniscient of the effects of antidepressants sertraline and venlafaxine (both of which I have been on in the past).