User blog comment:Mythomagius/One For All pushed to the limit/@comment-36170083-20180712193524/@comment-35202892-20180713091319

Well 1000000% was something of an exaggeration on Midoryia's part, see when he yelled it at one million percent it was more like 110-120%, or as some people theorise his real 100% punch. 1000000% was Izuku hyped on adrenaline, exclaiming that was simply a mental boost to increase his strength, it was not actually at one million percent. However, to answer your question, yes 1000000% would be similar to 8 gates, the only difference being that the 8 gates require chakra and push ones strength to beyond the limit of what they can do regularly. By opening the 8 gates, one is simply releasing strength that lay dormant in their bodies due to the drawbacks that it could have. The human bodie has restrictions that are placed practically at birth, what we consider "our strongest" would usually be around maybe a quatar to a fifth of our actual strength if we could use it unrestricted, however, the human body has placed a sort of lock on that strength so that we don't receive any drawbacks from it.

One For All is a boost to the the regular strength one has on a regular basis, increasing ones physical capabilities. Mind you that sentence is a hottly debated topic (some beleive that one for all is a boost to ones abilities specifically, for example, if todoroki was to gain one for all, his fire and ice's strength would increase a hundred-fold, whilst others believe, including me, that its a boost to ones physical capabilities and not ones quirk.), in any case one for all is similar to the 8 gates but not the same. All Might stated that One For All is the culmination of the users physical capabilites all stocked and used by each succesor, this is to say that every time someone takes on One For All, they gain the physical prowess that each of its users has had up until the point of passing on the quirk, which is why All Might can create tornado's with his punches. This strength is not the unristricted use of ones strength and physical capabilities; it is the collected strength of multiple people all piled onto one individual, who in turn must train his/her body to its peak physical condition constantly and get used to activating and using the quirk in their own unique ways.