Affinity Stone Calculator: How to Use It

The Affinity Stone Calculator works out the total number of affinity stones you need to fully upgrade a character or weapon in a gacha game, based on the current level, target level, and the number of duplicate items you have. You enter your current level, desired level, and how many duplicate copies you possess, and it returns the total stones required and the shortfall after using your duplicates. This guide explains the math behind the calculator, how to read its results, and the common mistakes players make when planning upgrades.

Formula

The calculator uses a cumulative sum formula. Each level requires a number of stones equal to that level number. So level 1 costs 1 stone, level 2 costs 2 stones, level 3 costs 3 stones, and so on. The total stones needed to go from level a to level b (inclusive of the target, exclusive of the current) is:

Total = [b(b+1)/2] – [a(a-1)/2]

• a = current level (the level you start from)
• b = target level (the level you want to reach)
• Total = number of affinity stones required, in stones

Each duplicate copy of the character or weapon gives a fixed bonus of 10 stones (this is a common value; check your game’s specific rules). The calculator subtracts dupes × 10 from the total to show how many stones you still need to farm or buy.

Worked Example

Using the default values: current level 1, target level 60, and 0 duplicates.

1. Calculate the sum for the target: 60 × 61 / 2 = 1830
2. Calculate the sum for the levels below current: 1 × 0 / 2 = 0
3. Total stones = 1830 – 0 = 1830 stones
4. After using 0 duplicates: 1830 – 0 = 1830 stones
5. Additional duplicates needed: ceil(1830 / 10) = 183 dupes

So from level 1 to level 60, you need 1,830 affinity stones in total. If you had 10 duplicates, you would subtract 100 stones, leaving 1,730 to obtain elsewhere.

When to Use This Calculator

Use this calculator whenever you are planning a major upgrade and want to know how many stones to stockpile before an event or banner. It is especially useful when you have a limited number of duplicates and need to decide whether to spend them now or save them for a future character. The calculator also helps you compare the cost of leveling multiple characters at once—just run it for each one and add the totals.

Because the formula assumes the cost per level is exactly equal to the level number, it works for any game that follows that linear progression. If your game uses a different curve (e.g., exponential or tiered costs), this calculator will not match your in-game numbers. Always verify with a few manual levels first.

How to Read the Results

The first output, Total stones needed, is the raw requirement. The second, Stones after using dupes, shows the remaining amount after you consume your duplicate copies. The third, Additional dupes needed, tells you how many more duplicate copies you would need if you wanted to skip farming entirely (assuming each dupe gives 10 stones).

If the “after dupes� number is zero, you have enough duplicates to finish the upgrade immediately. If it is positive, you need to farm stages, complete missions, or purchase stones. The “additional dupes� number is a ceiling—it rounds up because you cannot use a fraction of a duplicate.

Common Mistakes and Misconceptions

• Off-by-one errors: Many players calculate from level 1 to level 60 as 60 levels, but the formula correctly excludes the current level. From level 1 to 60, you need levels 2 through 60, which is 59 steps. The formula handles this automatically.
• Assuming a linear cost per level: Some games increase the cost per level by a fixed amount (e.g., +2 per level) rather than exactly the level number. This calculator only works for the simple cumulative model.
• Ignoring duplicate bonus variation: The 10-stone bonus per duplicate is a placeholder. Some games give 5, 20, or a percentage of the total. Always check your game’s duplicate system before relying on the output.
• Rounding too early: If you calculate manually, keep fractions until the end. The calculator rounds only the final “additional dupesâ€� value up to the next whole number.

Limitations of the Formula

This calculator is purely mathematical. It does not account for in-game sources of stones (events, daily rewards, shop purchases), nor does it consider whether duplicates are obtained through gacha pulls or other means. It also assumes you have enough resources to actually perform the upgrade—some games require a separate currency or item for each level-up, which is not included here.

If your game has a level cap that is not a simple integer (e.g., level 60 max but with a prestige system), you will need to adjust the target level accordingly. The calculator works best for games where the stone cost per level is exactly the level number, and where duplicates give a flat bonus.

Frequently Asked Questions

How do I find the stone cost per level in my game?
Check the in-game upgrade screen. Tap on the level-up button and note the stone count displayed. If it increases by exactly 1 each level, this calculator is accurate. If it jumps by 2 or 3, you need a different formula.

What if I have more duplicates than needed?
The calculator will show 0 for “stones after dupes� and 0 for “additional dupes needed.� Any extra duplicates are simply surplus and can be saved for another character or converted to other resources, depending on the game.

Can I use this for weapons and characters alike?
Yes, as long as both use the same stone cost progression. Many games have separate stone types for weapons and characters, but the leveling curve is often identical. Just make sure you are using the correct stone type in your calculations.

Why does the calculator show a different number than the game?
Possible reasons: the game rounds up or down at each level, the cost per level is not exactly the level number, or duplicates give a different bonus. Double-check a few manual levels to see where the discrepancy starts.

Is there a way to reverse the calculation?
Yes, you can input a target level and work backwards to see what level you can reach with a given number of stones. Use the calculator with a high target, then adjust until the total matches your stone count.

Do I need to include the current level in the total?
No. The formula subtracts the sum of levels below your current level. If you are at level 10, you do not need to pay for levels 1 through 9 again. The calculator does this automatically.

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in cur | Current level | - | 1 | 1
in target | Target level | - | 60 | 2
in dupes | Duplicate copies owned | - | 0 | 0
out total | Total stones needed | stones | (target*(target+1)/2) - (cur*(cur-1)/2) | 0
out after_dupes | Stones after using dupes | stones | max(0, total - dupes*10) | 0
out dupes_needed | Additional dupes needed | - | ceil(max(0, total - dupes*10) / 10) | 0