Attack Ratio Guide for OpenFront.io

Main Recommendation: To balance rapid expansion with sustainable growth, use an attack ratio of 50% during early bot engagements and transition to 20–30% against human players and fortified opponents.

1. Understanding Attack Ratio

The attack ratio determines what fraction of your available troops you commit when initiating an attack.

• A 1% ratio sends 1% of your troops; a 100% ratio sends your entire force.
• Adjust the ratio via the slider (Shift + Scroll Wheel) or hotkeys (1 to decrease, 2 to increase) .

2. Impact on Combat Speed

Attack speed (tiles conquered per tick) scales with the attacker-to-defender size ratio:

• For every 1% increase in attacker size (relative to defender troops), speed increases by:
  • 0.5% per 1% ratio increase when attacker force is between 5% and 10× the defender’s size
  • 0.1% per 1% ratio increase when attacker exceeds 10× defender size
• No speed bonus if attacker is smaller than 5% of defender troops
  (speed is also modified by terrain and empire size) .

3. Impact on Troop Losses

Troop losses per tick are governed by the Troop Ratio Factor, terrain, and a fixed 20% attacker bonus:

• Troop Ratio Factor = max(min(defender_troops / attacking_troops, 2), 0.6)
  • Attacking with less than half defender troops → factor hits 2× (higher losses)
  • Attacking with ≥166% of defender troops → factor hits 0.6× (minimum losses)
• Attacker Troop Loss = Troop Ratio Factor × Terrain Multiplier × 0.8 (attacker bonus) × Size Penalty × Traitor Penalty .
• To minimize losses, ensure your committed troops ≥166% of defender troops (ratio ≈ 1.66).

4. Speed vs. Efficiency Trade-Off

High attack ratios yield faster conquests but can deplete your shield (defending garrison) and slow population growth. Lower ratios conserve troops and shield but slow expansion.

Attack Ratio	Speed Bonus	Loss Efficiency	Recommended Use
50%	Moderate (+25%)	Acceptable (Troop Ratio Factor≈1–1.2×)	Early bot farming; balance growth vs. speed
20–30%	Small (+10–15%)	Efficient (minimize shield loss)	Mid-game human engagements; node skirmishes
≥166%	Max (+83%–100%)	Minimum losses (0.6× factor)	Quick snipes on key targets; decisive strikes

5. Terrain & Empire Size Modifiers

• Terrain Multipliers

  • Plains: –15% troop losses, +10% speed
  • Highlands: baseline
  • Mountains: +20% troop losses, –25% speed

• Size Penalty

  • Empires >100 000 tiles gain √(100 000 / tiles) reduction in losses
  • Empires >75 000 tiles incur slower conquest speed via (75 000 / tiles)^0.6 .

6. Practical Recommendations

1. Early Expansion (Bots & Wilderness)

   • Use 50% ratio against bots to farm quickly while retaining growth.
   • Exploit wilderness with high ratios for rapid tile gains (no defender losses) [Combat Against Wilderness].

2. Mid-Game Engagements

   • Lower ratio to 20–30% when contesting human players or strong bots to preserve shield and growth.

3. Decisive Strikes

   • Commit ≥166% ratio to snipe high-value enemy cities or break alliances swiftly with minimum losses.

4. Dynamic Adjustment

   • Monitor population growth bell curve (~42% of max pop) and adjust worker vs. troop ratios accordingly.
   • Rebalance attack ratio as your empire and frontline change.

7. Control Shortcuts

• Shift + Scroll Wheel: Fine-tune attack ratio
• 1 / 2: Decrease / Increase ratio in preset steps
• Left Click: Attack with current ratio

Citations:
Attack speed and losses mechanics detailed in the Combat and Attacking Guide pages .