Interactive Probability Calculator
Use the interactive calculator below to see exact probabilities for your character's dice pool.
Dice Pool Statistics
The statistics below show expected values and distributions for different pool sizes.
Success Rates by Pool Size
This chart shows how success rates improve as you add more dice to your pool.
Pool Size Matters
Larger pools produce more consistent results.
Explosions Are Powerful
Explosions add significant upside potential.
Success Tier Distribution
Success tiers show the distribution of outcomes for a given configuration.
Normal Success Dominates
Most successes fall in the Normal tier.
Critical Success Rarity
Critical successes are rare but dramatic.
Impact of Skills
Skills dramatically affect your success rate. A +5 skill bonus can shift outcomes by 20% or more.
Untrained Zone
Untrained characters struggle to meet even moderate difficulties.
Trained Zone
Trained characters can reliably meet moderate difficulties.
Expert Zone
Experts can tackle extreme challenges with confidence.
Impact of Imagination Points
Imagination Points can be spent to boost your rolls in several ways.
IP Tip
Consider the opportunity cost before spending IP.
Kept vs. Rolled Dice Strategy
Choosing to keep dice (auto-4) vs. rolling them is a key tactical decision.
When to Keep Dice
- You need guaranteed success at a specific TN
- You cannot afford to fail
- Your pool is large enough to absorb the variance
When to Roll Dice
- You need to reach higher success tiers
- You have room for failure
- You want to trigger explosions
Reach & Push Comparison
Reach and Push are two sides of the same coin—both alter your odds but with different risk profiles.
Reach
Reach adds dice now at the cost of future capability.
✓ Immediate boost to current roll
✗ Creates debt for your next test
Push
Pushing lets you reroll failed dice, but at a cost.
✓ Opportunity to succeed when you would otherwise fail
✗ Risk of taking a Wound if still failing
⚠️ DROP System v2 Probability Updates
The following sections cover probability analysis for new v2 mechanics.
Zero Dice Probability Analysis
Characters with 0 in an attribute face critical decisions. Here's how the two Zero Dice options compare:
| Option | Expected Value | Success vs TN 12 | Risk |
|---|---|---|---|
| 2d6 Take Lowest | ~2.53 | 0% | Safe (no State) |
| Reach for State | ~4.17 (with explosion) | 0% | Guaranteed State |
When to Take Lowest
Use when you can't afford a State, or when the TN is so high that even the Reach die won't help. Safe failure is better than dangerous failure.
When to Reach for State
Use when you desperately need success and have no other options. The State is guaranteed, but the extra ~1.6 average value could make the difference.
Sets: Probability by Pool Size
The probability of rolling matching dice (Sets) increases significantly with pool size. Here's how likely you are to roll at least doubles:
| Pool | Any Doubles | Any Triples | Expected Bonus |
|---|---|---|---|
| 2d6 | 16.7% | - | +0.17 dice |
| 3d6 | 44.4% | 2.8% | +0.50 dice |
| 4d6 | 72.2% | 9.7% | +0.82 dice |
| 5d6 | 90.7% | 19.4% | +1.11 dice |
| 6d6 | 98.5% | 31.9% | +1.38 dice |
Reach/Push Exclusivity: Strategic Analysis
In v2, once you Push you can no longer Reach until you rest. This creates a critical decision point that affects all future rolls in the session.
Reach-First Strategy
- ✓ Reach early when stakes are lower
- ✓ Build up Reach debt you can recover via Sets
- ✓ Save Push for critical moment
- ⚠️ Risk: accumulating Wound risk from 1s
Conservative Strategy
- ✓ Avoid both until necessary
- ✓ Use Sets to build dice organically
- ✓ Push only as last resort
- ⚠️ Risk: may fail winnable rolls
Single Explosion: Updated Probabilities
In v2, explosions are limited to once per die (no chains). This changes expected values:
| Mechanic | v1 Expected | v2 Expected | Change |
|---|---|---|---|
| Single d6 | 4.20 | 4.17 | -0.03 |
| Max single die | ∞ (theoretical) | 12 | Bounded |
| Explosion 1 = Fail? | Yes | No | Safer |
v2 Explosion Benefits
Rolling a 1 on an explosion die has no negative effects in v2. This makes explosions purely beneficial—there's never a downside to a die exploding.
Key Takeaways
For Players
- Always consider the risk-reward ratio before spending IP
- Keep dice when you need guaranteed success
- Roll dice when you need higher tiers
- Track your wound count to avoid the death spiral
For Tricksters
- Set difficulties based on the fiction, not the math
- Use the death spiral to create dramatic tension
- Remember that explosions can turn failures into successes
- Track player wound counts to anticipate their capabilities