The effect of refining depends on the grade rank of the equipment you are going to refine and of the type.
Phy Weapon: +phy dmg
Magic Weapon: +magic dmg
Phy Rings and phy. deff. amulettes/necklaces: +phy deff
Magic Rings and el. deff. amulettes/necklaces: +5 El. Deff
Dodge amulettes/necklaces: +dodge
any armor (incl. cloaks): +hp
Refined Level | Bonus Multiplier | Armor Effect | Weapon Effect |
+1 | x1 | +28 HP | +16 dmg |
+2 | x2 | +56 HP | +32 dmg |
+3 | x3.05 | +85 HP | +49 dmg |
+4 | x4.3 | +120 HP | +69 dmg |
+5 | x5.73 | +160 HP | +92 dmg |
+6 | x7.55 | +211 HP | +121 dmg |
+7 | x9.95 | +279 HP | +159 dmg |
+8 | x13 | +364 HP | +208 dmg |
+9 | x17.05 | +476 HP | +273 dmg |
+10 | x22.03 | +617 HP | +352 dmg |
+11 | x29 | +812 HP | +464 dmg |
+12 | x37.5 | +1050 HP | +600 dmg |
The Weapon Effect is for grade 9 weapons.
The Armor Effect is for grade 8 heavy armors.
How to calculate the effect for your refine bonus before you upgrade it:
take the bonus multiplier e.g. 4.3 for +4 equipment and the value from the list below and you will know, what the effect will be:
for grade rank 7 and below:
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for grade rank 8 and above:
light armors (mage): hp = grade rank*2 +1
mid armors and cloaks: hp = (grade rank-1)*3
heavy armors: hp = (grade rank-1)*4
weapons: dmg = (grade rank-1)*2
I hope someone can verify this and post some examples from AH below!
2 Examples how to figure out your effect:
A Wand Grade10 +5:
dmg addon = (grade rank-1) * 2 * bonus multiplier = 9 * 2 * 5.73 = 103.14 = 103 dmg
A Mid Armor Grade11 +6:
hp addon = (grade rank-1) * 3 * bonus multiplier = 10 * 3 * 7.55 = 226.5 = 227 hp
Examples I found on AH:
Light Armor Grade8: hp+17
Light Armor Grade9: hp+20
Mid Armor Grade6: hp+18
Mid Armor Grade7: hp+19
Mid Armor Grade8: hp+21
Mid Armor Grade9: hp+24
Mid Armor Grade10: hp+27
Heavy Armor Grade7: hp+26
Heavy Armor Grade8: hp+28
Heavy Armor Grade9: hp+32
Heavy Armor Grade10: hp+36
Heavy Armor Grade11: hp+40
Cloak Grade9: hp+24
Weapon Grade5: +11 dmg
Weapon Grade9: +16 dmg
Weapon Grade10: +18 dmg
Weapon Grade11: +20 dmg
Phy Ring Grade10: +27deff
Magic Ring Grade9: +20deff
Magic Necklace Grade8: +17deff