Rust upkeep is a daily tax your Tool Cupboard pulls to stop your base decaying. On default settings it costs between 10% and 33.3% of what the base cost to build, per 24 hours, depending on how many building blocks you have. Since September 2026 there is also a group tax once more than 4 players are tied to the base. Run out and each tier starts rotting away, from 1 hour for twig to 12 hours for armoured.
How upkeep works
Put wood, stone, metal fragments and high quality metal in your TC and it slowly eats them to keep the building it covers alive. Each material only pays for the parts built from it. A stone base with sheet metal doors burns stone and frags, and if you run out of stone, only the stone parts decay while the metal holds.
The TC shows how much of each material it needs for 24 hours, and how long the current stock will last. The default upkeep period is 1440 minutes, so every figure you see is per day.
What counts toward upkeep:
- Foundations, walls, floors, ceilings and roofs.
- Doors and window pieces.
What does not count: loot boxes, furnaces, sleeping bags and other furniture inside. High external walls are a special case: since the August 2026 Power Trip update they pay a flat 20% upkeep that ignores the block brackets, which makes big compounds of them expensive to keep.
How cost scales with base size
Each block is taxed at a rate set by how many blocks the base already has. On default server settings the brackets are:
| Blocks in the base | Tax rate on those blocks |
|---|---|
| First 15 | 10% |
| Next 50 (16 to 65) | 15% |
| Next 125 (66 to 190) | 20% |
| Everything past 190 | 33.3% |
Your displayed tax is the average across all blocks, so it creeps up instead of jumping. Corrosion Hour's example: a 20-block base pays 10% on 15 blocks and 15% on 5, which averages out to roughly 11%. The rate is applied to the build cost, so a small base that took 3000 stone to build pays about 300 stone a day.
This is why upkeep feels free on a 2x2 and painful on a clan compound. Blocks past 190 cost more than three times as much per day as your first 15.
Server owners can change all of this. The bracket sizes, cost fractions, upkeep period and decay speed are server convars, and some servers turn upkeep off completely. If a server's numbers look off, that is why.
The group tax (September 2026)
Breach and Clear added a second tax on top of the block brackets, based on how many players are tied to the TC:
| Players counted | Extra upkeep |
|---|---|
| 1 to 4 | none |
| 5 to 10 | +2% per player |
| 11 and up | +4% per player |
The total is capped at 300%. Six players adds 4%, twelve adds 20%.
The count is wider than just TC auth. It includes everyone authorised on the TC, everyone authorised on any code lock in the base (guest codes included), and anyone deauthorised from either in the last 24 hours. Hover over the upkeep cost with the TC open to see your current rate.
Decay times per tier
Once a material's upkeep runs out, the parts made from it start losing health. Default time for a block to decay fully:
| Tier | Decay time |
|---|---|
| Twig | 1 hour |
| Wood | 3 hours |
| Stone | 5 hours |
| Sheet metal | 8 hours |
| Armoured | 12 hours |
Decay starts at the outer parts of the base and works inward toward the core, so the honeycomb goes first and your loot room goes last. A base with no TC at all just decays from the start.
If someone destroys a locked TC that still has resources inside, it burns up to 24 hours of upkeep on the spot. Your base gets a day before decay kicks in, which is your window to log on and replace it.
How to lower your upkeep
- Stay small if you are a small group. A solo or duo base that stays under 65 blocks never leaves the cheap brackets.
- Do not overdo honeycomb. Every extra wall and floor pushes you into a higher bracket, and those blocks pay the top rate. Honeycomb only the sides that actually get raided.
- Use a separate TC for outbuildings. A shooting floor, farm or furnace hut that is not connected to the main base gets its own bracket count. Do not connect it to the main base with foundations, or it becomes part of the same building.
- Trim your code lock list. Since September, a teammate who quit three days ago still counts if they are on a code lock. Remove old auths and change codes when people leave.
- Watch high walls. At 20% static upkeep, a big compound of high external stone walls adds up fast.
- Upgrade if you go offline a lot. Higher tiers cost more per day but take longer to fall over once the TC runs dry, which buys time if you miss a refill.
- Stock a week, not a day. The TC shows how long its current stock lasts. Keep enough for several days so one missed session does not cost you the outer walls.
If you are deciding how thick to build, compare your upkeep against what it takes to blow through each layer with the raid calculator. The raiding guide shows which walls raiders actually target.