Very simple calc. The only problem is that this a first "legit" calc so detailed criticism is appreciated.
Feat: https://www.youtube.com/watch?v=X6mtCjo1A10
Kyoko Sakura: 1.56 Meters Height
Oktavia: 34.19 Meters Height (Just putting this in the off chance that I might need her height in a future calc)
Width: 115.15 Meters Wide
Now, as those who saw the video noticed, Sakura's blast produced a fireball explosion which completely engulfed the area shown, so I used a fireball calculator and got...
http://www.stardestroyer.net/Empire/Science/Nuke.html
Approx. 0.005 Megatons or 5 kilotons, so...
Formula 2[]
In the off chance that the Fireball method shouldn't be used. Here is what the NTR method version gets me, 2490.2153872 tons or 2.4902153872 kilotons, which interestingly enough, also lands Kyoko in the same Tier.
Results[]
Kyoko Sakura (and 3 in Attack Potency): At least Low 7-C (The At least comes from the fact that the blast had an unknown rate of expansion over the area above of the magical girl and the witch they fell from another sector into their final battlegrounds.), (Note: Only with the Fireball formula is Kyoko Small Town level+)
-Oktavia: At least 8-B (Mainly for the same reason as the other one, in which an unknown amount of terrain was created by Oktavia)
Credits: LordXcano, Amae (Original Creator), BlueDash (Senpai on the NTR formula)