Calculate soul stone fusion success rates for gacha, RPG, and tabletop games. Adjust inputs for base rates, material bonuses, and RNG modifiers to plan your fusion attempts. This tool helps players minimize resource waste and optimize fusion strategies.
Soul Stone Fusion Rate Calculator
Calculate success rates, expected attempts, and resource costs for fusion attempts in RPGs, gacha games, and tabletop titles.
Adjust for patch-specific RNG modifiers, seasonal events, or homebrew rules.
Fusion Calculation Results
How to Use This Tool
Follow these steps to calculate your soul stone fusion rates accurately:
- Enter the base success rate for your fusion recipe, found in your game’s patch notes or in-game menu.
- Input the number of soul stones required per fusion attempt, and the total number of fusion attempts you plan to make.
- Select the material tier you are using for the fusion, which applies a preset success bonus.
- Choose whether you will use Lucky Charms, which add a 10% success bonus at the cost of 1 charm per attempt.
- Adjust the RNG variance field if your game applies patch-specific random number generator modifiers.
- Click Calculate to view your adjusted success rate, expected successful fusions, resource costs, and confidence intervals.
- Click Reset to clear all inputs and start a new calculation.
- Use the Copy Results button to save your calculation data to your clipboard.
Formula and Logic
The calculator uses the following core logic to generate results:
- Adjusted Success Rate = Base Rate + Material Bonus + Lucky Charm Bonus + RNG Variance, clamped between 0% and 100%.
- Expected Successful Fusions = (Adjusted Success Rate / 100) * Planned Fusion Attempts.
- Resource Cost = (Soul Stones per Attempt * Planned Attempts) + (Lucky Charms Used ? Planned Attempts : 0).
- 95% Confidence Interval uses the normal approximation for binomial distributions: Adjusted Rate ± 1.96 * sqrt( (Adjusted Rate * (100 - Adjusted Rate)) / Planned Attempts ), clamped to 0-100%.
All calculations assume independent fusion attempts, as is standard for most gacha and RPG fusion systems.
Practical Notes
Soul stone fusion rates are often patch-dependent, so always verify base rates with the latest game updates before calculating.
- RNG variance values can shift between game patches, seasonal events, or limited-time fusion banners.
- Material tier bonuses may vary between games: the preset values here are standard for most AAA RPGs and gacha titles, adjust the RNG variance field to match your game’s specific modifiers.
- Lucky Charms are a common in-game item for fusion bonuses, but some games may call them Lucky Coins, Fusion Catalysts, or similar.
- For tabletop games, use the base rate provided by your game master or rulebook, and set RNG variance to 0 unless using homebrew modifiers.
- Competitive players should run multiple calculations with different RNG variance values to account for potential bad luck streaks.
Why This Tool Is Useful
This calculator helps players avoid wasting rare soul stones on low-success fusion attempts.
- Game designers can use it to balance fusion rates for new content, ensuring progression feels fair for players.
- Streamers can use real-time calculations to show viewers optimal fusion strategies during live gameplay.
- Competitive players can plan resource spending ahead of limited-time events to maximize high-tier gear drops.
- Tabletop gamers can quickly resolve fusion attempts without manual math slowing down gameplay sessions.
Frequently Asked Questions
What if my adjusted success rate goes above 100%?
The calculator automatically clamps adjusted rates to 100% maximum, as no fusion can have a higher success rate than guaranteed. Any bonus points above 100% are ignored in calculations.
How accurate is the 95% confidence interval?
The confidence interval uses standard statistical methods for independent events, which matches most video game fusion systems. For games with dependent RNG (where success rates increase after failed attempts), adjust the RNG variance field to a positive value to approximate this.
Can I use this for tabletop games like Dungeons & Dragons?
Yes, enter the success rate from your tabletop rulebook as the base rate, set material bonuses to 0 unless using homebrew items, and set RNG variance to 0 for standard d20-based fusion checks.
Additional Guidance
Always cross-check base fusion rates with official game sources, as datamined values may be inaccurate or outdated.
- Save your calculation results using the Copy to Clipboard button to track fusion performance over multiple sessions.
- If your game has a "pity system" where success rates increase after consecutive failures, run calculations with incremental RNG variance values to model this.
- For gacha games with limited-time fusion banners, calculate rates for both standard and banner-boosted material tiers to decide if the banner is worth pulling for.
- Game designers should test fusion rates with a range of RNG variance values to ensure casual and competitive players both have viable progression paths.