Base Building and Economy
Supplies are the only thing you spend in Halo Wars, so put two or three Supply Pads on your first empty base slots before anything else. A base opens with 3 slots and reaches 7 only after two paid tier upgrades, so every slot you spend on economy is one you cannot spend on Reactors or unit production. The UNSC raises its tech level with Reactors while the Covenant runs all of its tech through a single Temple.
A strong economy wins matches in Halo Wars: Definitive Edition. You cannot build units without supplies. You cannot unlock advanced units without tech levels. Managing your base slots efficiently is the most important skill to learn.
The Slot System
Unlike traditional RTS games, you do not place buildings freely on the map. You claim a base location, and that location provides a set number of building slots.
A base does not start with seven slots. It opens with 3 and grows through two paid tier upgrades, gaining 2 slots each time, to a maximum of 7. Both factions follow the same progression under different names:
| Faction | Tier 1 | Tier 2 | Tier 3 |
|---|---|---|---|
| UNSC | Firebase, 3 slots | Station, 5 slots | Fortress, 7 slots |
| Covenant | Outpost, 3 slots | Keep, 5 slots | Citadel, 7 slots |
Dropping the initial base costs 500 resources for either faction. The UNSC then pays 400 and 400 for its two upgrades, while the Covenant pays 300 and 400. The tier 2 upgrade also adds four turret foundations, which sit outside the building slots.
Smaller Minibases exist on many maps with far fewer slots. The Covenant Minibase supports a single additional structure.
Every decision is a trade-off. If you build five Supply Pads, you have an incredible economy but no room for unit production buildings. If you build three unit production buildings, your economy will suffer.
Gathering Supplies
Supplies are the only thing you actually spend. The game also tracks Tech and Population, but those gate what you can build and are never currencies you hand over. You spend supplies on structures, units, upgrades, and Leader Powers.
Supply Pads and Warehouses
The UNSC builds Supply Pads. The Covenant builds Warehouses. These structures generate supplies over time.
Always build Supply Pads on your first few empty slots. The standard opening for almost every strategy is to build two or three Supply Pads immediately.
Upgrade your supply buildings as soon as possible. The upgrades are the Heavy Supply Pad and the Blessed Warehouse, each costing 225 resources at Tech 1. Sergeant Forge's Supply Pads start as Heavy Supply Pads, so he skips that 225 entirely on every pad. This makes him the strongest economic Leader in the game.
Map Resources
Blue supply crates spawn across the map at match start, and more appear when neutral bases fall. Any infantry or scout unit can capture them, so you are not limited to your starting Warthog or Ghost. Grab them early for the boost.
Managing Tech Levels
Tech levels gate your advanced units and upgrades. You start at Tech 0, not Tech 1.
The two factions do not share a ceiling. The UNSC caps at Tech 4, while the Covenant caps at Tech 3. Both reach every unit in their own roster at their own cap.
UNSC Tech
The UNSC builds Reactors, and each one raises your tech level by one.
Reactors get more expensive as you add them. The first costs 250 resources, and every Reactor after that costs 250 more than the last, so the second is 500 and the third is 750.
- Tech 1: One Reactor. Unlocks basic upgrades and early vehicles.
- Tech 2: Two Reactors. Unlocks advanced units like Scorpions and Hornets.
- Tech 3: Three Reactors. Unlocks the best units and final upgrades.
- Tech 4: The UNSC ceiling.
Reactors take up valuable base slots. You can upgrade an existing Reactor into an Advanced Reactor for 1,200 resources, which outputs power equal to two Reactors from the same slot. Two Advanced Reactors therefore reach Tech 4 using only two slots instead of four. It is expensive but it buys back the space.
Covenant Tech
The Covenant runs all of its tech through a single Temple, and only one can exist at a time. Building it costs 500 resources and grants Tech 1. You then raise tech by upgrading the Temple itself, through Age of Doubt for 1,000 resources and Age of Reclamation for 2,000, reaching the Covenant ceiling of Tech 3.
If the enemy destroys your Temple, your tech level drops straight to 0 until you rebuild it. Protect it with Shield Generators, which cost 200 resources at Tech 1 and stack, since multiple generators compound the shield's strength.
Upgrading your Citadel tier adds building and turret slots. It does not raise your tech level. Those are two separate investments and it is worth keeping them straight when planning a build.
Securing Expansions
One base is never enough for a long game. You need expansions. Look for empty base plots on the map. Clear out the neutral forces guarding them, which can be Rebel infantry from the Insurrectionist faction, Sentinels, or the Flood, all of which are hostile to the UNSC and Covenant alike. Build a new base to double your supply generation.
If your opponent gets a second base and you do not, you will lose a war of attrition. They will simply out-produce you. Always scout for expansion opportunities and deny your opponent their expansions.
Frequently Asked Questions
How many building slots does a base have in Halo Wars?
A base opens with 3 slots and reaches a maximum of 7 through two paid tier upgrades that add 2 each. The UNSC goes Firebase to Station to Fortress and the Covenant goes Outpost to Keep to Citadel. Minibases have far fewer, with the Covenant Minibase supporting a single structure.
What should I build first in Halo Wars?
Build two or three Supply Pads on your first empty slots. Supplies pay for structures, units, upgrades, and Leader Powers, so the standard opening for almost every strategy starts with economy.
How do I reach Tech Level 4 without wasting base slots?
Upgrade an existing Reactor into an Advanced Reactor for 1,200 resources. It outputs power equal to two Reactors from the same slot, so two Advanced Reactors reach Tech 4 using two slots instead of four. Note that Tech 4 is the UNSC ceiling. The Covenant caps at Tech 3.
What does a Reactor cost in Halo Wars?
The first costs 250 resources, and each additional Reactor costs 250 more than the last, so the second is 500 and the third is 750. You also start the match at Tech 0, not Tech 1.
Which leader has the best economy in Halo Wars?
Sergeant Forge. His Supply Pads start as Heavy Supply Pads, so he skips the 225 resource upgrade that every other leader pays on each pad.
What happens if my Covenant Temple gets destroyed?
Your tech level drops straight to 0 until you rebuild it, because the Temple is the sole source of Covenant tech. Protect it with Shield Generators, which cost 200 resources and stack, since multiple generators compound the shield strength.
Does upgrading my Citadel raise my Covenant tech level?
No. Citadel tier upgrades add building and turret slots only. Tech comes from the Temple and its Age of Doubt and Age of Reclamation upgrades. Keep the two investments separate when planning a build.
What to Read Next
- Combat and Units. Build times and supply costs your economy has to cover.
- Multiplayer and Skirmish. Contesting expansions and map control.
- Factions and Leaders. Leader powers that change your economic curve.
- Tips and Tricks. Reactor pricing, slot growth, and what a Citadel upgrade does not buy.