TI4 Combat Calculator
An essential tool for predicting space combat outcomes in Twilight Imperium 4th Edition. This TI4 calculator helps you determine the average number of hits your fleet will produce in a single round of battle.
Attacker’s Fleet
Defender’s Fleet
Expected Combat Results (Per Round)
Intermediate Calculations
Attacker Hits by Unit: Not yet calculated
Defender Hits by Unit: Not yet calculated
This result shows the statistical average number of hits and does not account for dice variance, action cards, or abilities.
Expected Hits by Unit Type
What is a TI4 Calculator?
A TI4 calculator is a specialized tool designed for players of the board game Twilight Imperium 4th Edition. Its primary purpose is to help players make informed decisions during space combat by calculating the probable outcomes. Instead of relying purely on gut feeling, this TI4 calculator provides a statistical analysis of a fleet engagement, showing the average number of ‘hits’ each side can expect to score in a single round of combat. This allows players to assess risks, commit forces more effectively, and understand the true power of their fleet compositions before a single die is rolled.
This is crucial in a game where a single miscalculated battle can have galaxy-spanning consequences. Understanding the math behind the plastic spaceships is a key skill for any aspiring emperor, and a TI4 calculator is the perfect instrument for that job.
The TI4 Calculator Formula and Explanation
The core of the TI4 calculator is based on a simple probability formula. Each ship in Twilight Imperium has a ‘Combat’ value. To score a hit, a player must roll a 10-sided die and get a result equal to or greater than the ship’s Combat value. The formula for a single ship’s expected hits per round is:
Expected Hits = (Number of Dice) * (11 – Combat Value) / 10
The total expected hits for a fleet is the sum of the expected hits from all ships in that fleet. For example, a Cruiser hits on a 7, 8, 9, or 10. That’s 4 possible successful outcomes out of 10, or a 40% chance (0.4 expected hits). Our TI4 calculator applies this logic to every ship in your fleet to give you a total.
| Variable (Unit) | Meaning (Combat Value) | Unit (Roll needed on d10) | Typical Range (Expected Hits/Round) |
|---|---|---|---|
| War Sun | Rolls 3 dice, hits on 3+ | 3 or higher | 2.4 |
| Dreadnought | Hits on 5+ | 5 or higher | 0.6 |
| Cruiser | Hits on 7+ | 7 or higher | 0.4 |
| Carrier | Hits on 9+ | 9 or higher | 0.2 |
| Destroyer | Hits on 9+ | 9 or higher | 0.2 |
| Fighter | Hits on 9+ | 9 or higher | 0.2 |
Practical Examples
Example 1: Early Game Skirmish
An attacker with 2 Cruisers and 2 Fighters engages a defender with 1 Dreadnought.
- Attacker Inputs: 2 Cruisers, 2 Fighters.
- Defender Inputs: 1 Dreadnought.
- Calculation:
- Attacker: (2 Cruisers * 0.4 hits) + (2 Fighters * 0.2 hits) = 0.8 + 0.4 = 1.2 Expected Hits
- Defender: (1 Dreadnought * 0.6 hits) = 0.6 Expected Hits
- Result: Statistically, the attacker has a significant advantage in this combat round. The TI4 calculator shows they are likely to inflict twice as much damage.
Example 2: Late Game Fleet Clash with Upgrades
An attacker with 1 War Sun, 2 Dreadnoughts, and the ‘Plasma Scoring’ technology (+1 to all combat rolls, effectively -1 to the target number) attacks a defender with 5 Cruisers and 5 Fighters.
- Attacker Inputs: 1 War Sun, 2 Dreadnoughts, Plasma Scoring checked.
- Defender Inputs: 5 Cruisers, 5 Fighters.
- Calculation:
- Attacker: (1 War Sun * (11-2)/10 * 3 dice) + (2 Dreadnoughts * (11-4)/10) = 2.7 + 1.4 = 4.1 Expected Hits
- Defender: (5 Cruisers * 0.4 hits) + (5 Fighters * 0.2 hits) = 2.0 + 1.0 = 3.0 Expected Hits
- Result: Despite having fewer ships, the attacker’s high-quality units and technology give them a clear advantage. Our ti4 calculator demonstrates the power of War Suns and key technologies. For more details, see a TI4 Faction Strategy Guide.
How to Use This TI4 Calculator
- Enter Attacker’s Fleet: In the “Attacker’s Fleet” section, input the number of each ship type participating in the combat.
- Enter Defender’s Fleet: Do the same for the defending player in the “Defender’s Fleet” section.
- Select Modifiers: Check boxes for relevant technologies like ‘Plasma Scoring’ for each side. This TI4 calculator automatically adjusts the combat values.
- Calculate: Click the “Calculate Expected Hits” button.
- Interpret Results: The main result will show the total expected hits for each fleet per round. The intermediate results break this down by ship type, and the bar chart provides a visual comparison. This helps you understand not just who is winning, but which ships are contributing most. Check out our guide on TI4 Combat Essentials for more.
Key Factors That Affect a TI4 Calculator
While this TI4 calculator provides a strong baseline, many factors can influence the actual outcome of a battle:
- Technology Upgrades: Technologies like Plasma Scoring (included here) or unit upgrades (e.g., Cruiser II) dramatically alter combat values.
- Faction Abilities: Many factions (like the Barony of Letnev or the Naalu Collective) have abilities that directly modify combat rolls or steps.
- Action Cards: Cards like ‘Morale Boost’ (+1 to all rolls) or ‘Direct Hit’ (destroy a ship outright) can swing a battle. Always consider your opponent’s hand.
- Sustain Damage: Dreadnoughts and War Suns can take a hit without being destroyed. This calculator shows expected hits, not final casualties. Remember to factor in which hits can be sustained.
- Anti-Fighter Barrage: Destroyers and certain other units can fire at fighters before the main combat begins, which can neutralize a fighter screen. This should be considered before using the main ti4 calculator. A good TI4 Tech Path Planner can help you prioritize these key upgrades.
- Dice Variance: This is the most unpredictable factor. A TI4 calculator deals in averages, but a hot or cold streak of rolling can defy the odds. The calculator tells you what *should* happen, not what *will* happen.
Frequently Asked Questions (FAQ)
1. Is this result guaranteed?
No. This TI4 calculator computes the statistical average (the expected value) of hits. Due to the randomness of dice rolls, the actual number of hits can be higher or lower. It’s a tool for assessing probability, not predicting the future with certainty.
2. How does the ‘Plasma Scoring’ checkbox work?
When checked, the TI4 calculator reduces the combat value needed for a hit by 1 for all ships on that side. For example, a Cruiser that normally hits on a 7+ will now hit on a 6+, increasing its expected hits from 0.4 to 0.5 per round.
3. Why doesn’t this calculator include Sustain Damage?
This calculator focuses on hit generation. Applying hits is a separate tactical decision. You can use the “Expected Hits” output to determine how many hits you need to assign, and then decide which ones to assign to ships with Sustain Damage.
4. What about Anti-Fighter Barrage?
Anti-Fighter Barrage occurs before the first round of space combat. You should resolve those rolls first and remove any destroyed fighters before inputting the remaining fleets into this TI4 calculator for the main combat rounds.
5. Does this work for ground combat?
No, this is specifically a space combat TI4 calculator. Ground combat uses different unit values and a simpler combat sequence. A dedicated TI4 Ground Combat Analyzer would be needed.
6. How should I use the ‘Copy Results’ button?
This button is great for sharing combat simulations with other players. It copies a clean summary of the fleets and the expected results to your clipboard, perfect for pasting into a chat or forum post.
7. Why are fighters so effective in large numbers?
While a single fighter is weak, they are cheap to produce and each one provides an additional “hit point” for the fleet that must be chewed through. A large fighter screen can absorb many hits, protecting your more valuable capital ships. This is often called “HP wins” in the community, a principle well explored in our Advanced TI4 Fleet Composition article.
8. Are unit upgrades (e.g. Dreadnought II) included?
This version of the TI4 calculator uses the base unit stats for simplicity. Future versions may include toggles for specific unit upgrades. For now, you can manually adjust for them or consult a Complete TI4 Unit Stats Reference.