This page should give you an overview about the bonuses, which the AI or the player receive depending on difficulty level in Civilization 5. Please note that not all values are clear yet.

If you can clarify some of the values, or would like to contribute, then please post in this thread.

Player Bonuses

These are the handicaps given to players playing at the specified difficulty level. These typically only grant bonuses for difficulties below prince.

Settler Chieftain Warlord Prince King Emperor Immortal Deity Advanced Start Points 150% 130% 110% 100% 90% 85% 80% 75% Base Happiness 15 12 12 9 9 9 9 9 Extra Happiness Per Luxury 1 1 0 0 0 0 0 0 Unhappiness Per City 40% 60% 75% 100% 100% 100% 100% 100% Unhappiness Per Population 40% 60% 75% 100% 100% 100% 100% 100% Production Free Units 10 7 7 5 5 5 5 5 Production Free Units Per City 3 3 2 2 2 2 2 2 Route Cost 34% 50% 75% 100% 100% 100% 100% 100% Unit Cost 50% 67% 85% 100% 100% 100% 100% 100% Building Cost 50% 67% 85% 100% 100% 100% 100% 100% Research Cost 90% 95% 100% 100% 100% 100% 100% 100% Policy Cost 50% 67% 85% 100% 100% 100% 100% 100% City Production Num Options Considered 10 4 3 2 2 2 2 2 Tech Num Options Considered 10 4 3 2 2 2 2 2 Policy Num Options Considered 10 4 3 2 2 2 2 2 Attitude Change 2 1 0 -1 -1 -1 -1 -1 No Tech Trade Modifier 100% 90% 80% 70% 50% 40% 30% 20% Tech Trade Known Modifier -100% -50% -25% 0% 0% 0% 0% 0% Barb Camp Gold 50 40 30 25 25 25 25 25 Barb Spawn Mod 8 5 3 0 0 0 0 0 Barbarian Bonus 75 50 40 33 25 20 10 0 Turn Barbarians Can Enter Player Land 10000 60 20 0 0 0 0 0 Barbarian Land Target Range 2 3 4 5 5 6 7 8 Barbarian Sea Target Range 4 6 8 10 12 15 18 20

AI Bonuses

These are the mods given to all the AI when the player chooses a given difficulty level. The AI plays at chieftain difficulty level and get those bonuses as well; eg, if the player chooses deity, in addition to the 60% unhappiness listed below, the AI has 60% from playing at chieftain difficulty and those get multiplied together, resulting in 36% unhappiness from cities and population for the AI.