Earlier in this thread I made a post regarding a simple way to go about estimating how often a pure bluff needs to work given a certain bet size and pot size.

An extension to this would be the semi bluff. The calculation is pretty similar to pure bluffing, however it differs slightly in that we now account for the equity we have in the pot. If we want to find the break even fold frequency of a semi-bluff, there is a pretty neat 2 step process we can adhere to. This is a pretty awesome way to roughly estimate your fold equity when semibluffing. It's simple enough that you could do this on the fly while grinding. (I give credit to spoonitnow for this btw)

Step 1: Find the b/e % of betting as if you were pure bluffing
Step 2: Subtract 10% from what you get from step 1 for every 4 outs you have

Example: Say we bet $40 into a $50 pot with an OESD. If we were simply pure bluffing, using step 1 we can see the b/e % as a pure bluff is $40/$90 = 44.4%. Now since we have 8 outs, we subtract 20% from that and voila. This bumps down our needed fold equity to about 24%!

Looks like semi-bluffing is a pretty f'in powerful weapon. Something to keep in mind is this is just a rough estimation. As our outs start increasing beyond 12 the calculation breaks down a bit regarding its accuracy. Also, if we bet more than 2x the pot it starts to get a lil off as well. Hopefully you other busto donks realize the power of semi-bluffing through what as been shown here.