Post written by Kevin “qxc” Riley of compLexity Gaming.
Starcraft is all about increasing your army as quickly as possible. The faster your supply on the field grows, the better your position will generally be. Nothing hinders growth more than getting supply blocked. Early on, missing just 1 or 2 supply at the correct times will make it impossible to defend certain timings. As the game goes longer, supply growth increases dramatically and supply
producing production must increase as well.
Early game example: 3 rax, 1 reactor port = ~10 supply / 30s which is ~1.5 depots
Late game Example: 8 rax, 2 factories, 1 reactor port = ~26 supply / 30s which is ~3 depots.
Optimal growth dictates that supply is built as needed. If you build supply at the expense of units, then you won’t be making units as quickly as possible. Likewise, if you queue up too much and end up with no supply you’ll be stuck. Of these two situations, being supply stuck is almost always worse. You would rather purposely delay production than be unable to build anything at all. Especially since some units are more important than others.
Example: If I’m low on money, I can prioritize Medivacs and Widow Mines over Marines because just a few of these non-bio units will increase my overall army efficiency much more than the corresponding value of bio. If I’m supply blocked, my only immediate production option is to build more depots.
Early in the game it’s relatively easy to keep track of supply depots and macro optimally as there’s less action in general and the early game is also generally more practiced. As the game goes longer, there’s a lot more action on the map which makes maintaining optimal macro more difficult. This trick will help keep your macro a little more stable as the action heats up.
The first general tip is always try to stay 1-2 supply structures ahead of what you need once you get into the 70+ supply range. If all your production is queued up, you still want somewhere on the order of 8-16 supply left over to account for human error or unexpected events that take your concentration away from macro.
As soon as you’re at full 3 base production and around 120+ supply, build all the rest of your supply required. This may involve cutting your production for a short time, but will help overcome human error and open you up to focus more on being active on the map. Depending on how many supply structures you build at once you should only end up delaying your production on the order of 10-20 seconds. While this may seem like a lot of time, the cost of a full supply block is much higher.
In order to finish your supply as effectively as possible, you’ll want to keep track of general supply numbers. For Terran it’s something like this:
| Current Max Supply | Depots Until /200 |
| 121 | 10 |
| 129 | 9 |
| 137 | 8 |
| 145 | 7 |
| 153 | 6 |
| 161 | 5 |
| 169 | 4 |
| 177 | 3 |
| 185 | 2 |
| 193 | 1 |
| 200 | 0 |
By being familiar with these numbers I can easily look at my supply and build exactly the number of depots I need for the rest of the game. If you’re having trouble remembering these numbers, just try to remember that it’s 10 from 120, and 5 from 160 and approximate from there. Always err on the side of over building supply, rather than under building and that will also help protect you in case you lose some supply providing structures in the future.