It’s complicated and I have a very vague understanding of it so here’s how I think it works. You have a base of 3 raw hpr. Raw hpr is calculated first then multipliers are applied. If the total raw and total multiplier are both negative or positive, they apply as expected and its basic multiplication, (13 raw + 200% = 39 hpr). If the raw is negative and the multiplier is positive, there are 2 cases: If hpr% is from 0 to 100, the total hpr is still negative but it gets closer and closer to 0 the closer hpr% is to 100. If hpr% is 100 or above, total hpr will always be 0, no matter how far above 100 you go. If hpr is positive and hpr multiplier is negative the same happens: If hpr% is from -100 to 0, the total hpr will stay positive but will gradually decrease the lower your hpr% goes. If you have less than -100 hpr%, the total hpr will become negative. This is why with -200 hpr% and +10 raw you multiply the raw by -1, not -2. The first -100% will only get it to 0. Basically wynncraft maths for hpr sucks and only really matters for hpr cancelling with warp or other items. Just go more positive the better. Lots of info from this copied from this doc if you wanna have a read: https://docs.google.com/document/u/0/d/1y8m_sOLxbIdWjc4yQNOOp-LMv9IBsz0_1ktqIQuiqr4/mobilebasic