Grinding

Weapon grinding is the process of strengthening weapons, increasing their ATP/TP and PP by reasonable amounts.

All weapons start at 0, and can be ground up to an initial maximum level of 10. The downside to grinding is that, if grinding fails, the weapon will revert back to an initial grind of 0. This happens each time a weapon breaks.

How to Grind

In order to grind, you must first have Grinders with which to grind the weapon. The grinder must be of equal or greater Weapon Rank compared to the weapon you wish to grind (e.g. you can grind a C-rank weapon with any grade of grinder, while S-rank weapons can only be ground using S-rank grinders). Different Grinders of the same Rank may be of different quality (represented by a number e.g. +1 or +4), thus affecting the success rate of the grinding. If you have the grinders, you must go to the Grinding Shop of the manufacturer of the weapon you wish to grind. For example, G.R.M. weapons can be ground at the G.R.M. Shop in Holtes City west on Parum, and Yohmei weapons are ground at the Yohmei Shop in Ohtoku City on Neudaiz. Kubara weapons need to be taken to the Junk Shop on the second floor of the GUARDIANS Colony to be ground. Also, remember to remove the weapon from the action palette before attempting to grind it. If you do not do so, you will not be able to grind the weapon.

Grinding Success Rates

The odds for the grinding process to succeed are dependent on the following factors:

• The level of the weapon's current grind (0 to 9)
• The quality of the grinder (+1 to +10)

Shorthand	In-game Message	Actual Chance
Guaranteed	There is no chance of failure.	100%
Very High	The probability of success seems very high.	80% ~ 99%
High	The probability of success seems high.	60% ~ 79%
Fifty-Fifty	The probability of success seems to be about fifty-fifty.	40% ~ 59%
Low	The probability of success seems low.	20% ~ 39%

It should be noted that, due to the way Phantasy Star Universe deals with its random number generation, it is technically possible to fail a grind with a 100% success rate. Yes, it is very annoying.

During periods where a grind boost is active, the numbers in the tables below will be increased by the amount specified. So for instance, during a 10% grind boost, the chance of successfully grinding a weapon from 9-10 using a Grinder S+10 goes from its usual 47% to 57%.

Success Rate Tables

C-Rank Weapons

Grind	Grinder
	+1	+2	+3	+4	+5	+6	+7	+8	+9	+10
0 → 1	100%	100%	100%	100%	100%	100%	100%	100%	100%	100%
1 → 2	100%	100%	100%	100%	100%	100%	100%	100%	100%	100%
2 → 3	91%	92%	93%	94%	95%	96%	97%	98%	100%	100%
3 → 4	89%	90%	91%	92%	93%	94%	95%	96%	97%	98%
4 → 5	85%	86%	87%	88%	89%	90%	91%	92%	93%	94%
5 → 6	79%	80%	81%	82%	83%	84%	85%	86%	87%	88%
6 → 7	71%	72%	73%	74%	75%	76%	77%	78%	79%	80%
7 → 8	67%	68%	69%	70%	71%	72%	73%	74%	75%	76%
8 → 9	61%	62%	63%	64%	65%	66%	67%	68%	69%	70%
9 → 10	57%	58%	59%	60%	61%	62%	63%	64%	65%	66%

B-Rank Weapons

Grind	Grinder
	+1	+2	+3	+4	+5	+6	+7	+8	+9	+10
0 → 1	100%	100%	100%	100%	100%	100%	100%	100%	100%	100%
1 → 2	92%	93%	94%	95%	96%	97%	98%	100%	100%	100%
2 → 3	86%	87%	88%	89%	90%	91%	92%	94%	96%	98%
3 → 4	80%	81%	82%	83%	84%	85%	86%	87%	88%	90%
4 → 5	76%	77%	78%	79%	80%	81%	82%	83%	84%	85%
5 → 6	74%	75%	76%	77%	78%	79%	80%	81%	82%	83%
6 → 7	70%	71%	72%	73%	73%	74%	74%	75%	76%	77%
7 → 8	61%	62%	63%	64%	65%	66%	68%	69%	70%	71%
8 → 9	55%	56%	57%	58%	59%	60%	61%	62%	63%	64%
9 → 10	51%	52%	53%	54%	55%	56%	57%	58%	59%	60%

A-Rank Weapons

Grind	Grinder
	+1	+2	+3	+4	+5	+6	+7	+8	+9	+10
0 → 1	100%	100%	100%	100%	100%	100%	100%	100%	100%	100%
1 → 2	89%	90%	90%	91%	92%	93%	93%	96%	96%	97%
2 → 3	80%	81%	82%	83%	84%	85%	86%	89%	90%	91%
3 → 4	77%	78%	79%	80%	80%	81%	82%	84%	85%	86%
4 → 5	72%	73%	73%	74%	75%	75%	76%	78%	79%	80%
5 → 6	64%	64%	65%	66%	67%	68%	69%	72%	73%	73%
6 → 7	59%	60%	61%	62%	62%	63%	63%	66%	66%	67%
7 → 8	54%	54%	55%	56%	56%	56%	57%	60%	61%	62%
8 → 9	46%	47%	48%	49%	50%	51%	52%	55%	56%	57%
9 → 10	41%	42%	43%	44%	45%	46%	47%	50%	51%	52%

S-Rank Weapons

Grind	Grinder
	+1	+2	+3	+4	+5	+6	+7	+8	+9	+10
0 → 1	95%	96%	97%	98%	100%	100%	100%	100%	100%	100%
1 → 2	87%	88%	89%	90%	90%	91%	91%	94%	94%	95%
2 → 3	78%	79%	80%	81%	82%	83%	84%	87%	88%	89%
3 → 4	76%	77%	78%	79%	79%	80%	80%	83%	84%	85%
4 → 5	69%	69%	70%	70%	71%	72%	72%	75%	75%	76%
5 → 6	57%	58%	59%	60%	61%	62%	63%	66%	66%	67%
6 → 7	54%	55%	56%	57%	58%	59%	59%	62%	62%	63%
7 → 8	49%	50%	51%	52%	52%	53%	54%	57%	57%	58%
8 → 9	44%	45%	45%	46%	47%	47%	48%	50%	51%	52%
9 → 10	39%	40%	40%	41%	41%	42%	42%	45%	46%	47%