Rust Decay Calculator
How long your base survives with no upkeep, what the Tool Cupboard charges per 24 hours, and how long your stock lasts — using the real progressive upkeep tax brackets and verified decay times per building tier.
Decay & Upkeep Calculator
1. Your building pieces
2. Tool Cupboard stock (optional)
Results
Upkeep is charged per resource and rounded up per the in-game rule. Costs use standard wall-piece build costs; foundations and doors can differ — verify in game for full precision.
Decay & Upkeep Reference — All Tiers
| Tier | Wall HP | Decay, no upkeep (outdoor) | Decay, sheltered/indoor | Build cost / piece | Upkeep / piece / 24h |
|---|---|---|---|---|---|
| Twig | 10 | 1 hour | 1 hour* | 50 wood | 5–17 wood |
| Wood | 250 | 3 hours | 30 hours | 200 wood | 20–67 wood |
| Stone | 500 | 5 hours | 50 hours | 300 stone | 30–100 stone |
| Sheet Metal | 1,000 | 8 hours | 80 hours | 200 metal frags | 20–67 frags |
| Armoured | 2,000 | 12 hours | 120 hours | 25 HQM | 3–9 HQM |
* Twig gets no shelter bonus (anti-griefing design): it always decays in 1 hour once upkeep stops. Upkeep per piece ranges from the 10% bracket to the 33.3% bracket. Decay times are official Facepunch defaults; admins can change them.
Worked Examples
Example 1 — 12-block stone starter
Blended tax rate: 10.0% → 360 stone per day. Decay with no upkeep: 5.0 hours.
Math: 12 x 300 stone build cost = 3,600 stone; all 12 blocks sit in the 10% bracket → 3,600 x 10% = 360 stone per day. This matches the in-game Tool Cupboard readout for a starter base.
Example 2 — 140-block mixed base (100 stone + 40 sheet metal)
Blended tax rate: 17.14% → 5,143 stone + 1,372 metal frags per day.
Math: (15 x 10% + 50 x 15% + 75 x 20%) / 140 = 17.14%. Stone: 17.14% x 100 x 300 = 5,142.86 → 5,143/day (rounded up). Frags: 17.14% x 40 x 200 = 1,371.43 → 1,372/day (rounded up).
Example 3 — 30-piece twig starter
Blended tax rate: 12.5% → 188 wood per day. Decay with no upkeep: 1.0 hour.
Math: (15 x 10% + 15 x 15%) / 30 = 12.5%. Wood: 12.5% x 30 x 50 = 187.5 → 188/day (rounded up). Twig always decays in 1 hour once the cupboard runs dry — no shelter bonus.
Example 4 — 20-piece armoured core
Blended tax rate: 11.25% → 57 HQM per day. Decay with no upkeep: 12.0 hours.
Math: (15 x 10% + 5 x 15%) / 20 = 11.25%. HQM: 11.25% x 20 x 25 = 56.25 → 57/day (rounded up).
Example 5 — How long does TC stock last?
20,000 stone + 5,000 metal frags on the 140-block base → stone lasts 3.89 days, frags last 3.64 days. Limiting resource: Metal Frags — the TC runs dry in about 3.64 days.
Math: 20,000 / 5,143 = 3.89 days of stone; 5,000 / 1,372 = 3.64 days of frags. Upkeep is charged per resource, so the soonest to run out sets the deadline.
Frequently Asked Questions
On default server settings, a building piece at full health with no Tool Cupboard upkeep decays completely in: Twig: 1 hour; Wood: 3 hours; Stone: 5 hours; Sheet Metal: 8 hours; Armoured: 12 hours. These are the official default values from the Facepunch wiki. Server admins can change them, and damaged pieces decay faster because decay time scales with current health.
Every 24 hours the Tool Cupboard consumes resources to repair your base. The cost is a progressive tax on each building block's build cost: the first 15 blocks are taxed at 10 percent, blocks 16 to 65 at 15 percent, blocks 66 to 190 at 20 percent, and every block beyond 190 at 33.3 percent. The game blends these into one effective rate. For example, a 20-block base pays (15 x 10% + 5 x 15%) / 20 = 11.25% of its total build cost per day.
Multiply the blended tax rate by the build cost. A 12-block stone starter costs 12 x 300 = 3,600 stone to build, all inside the 10 percent bracket, so it needs 360 stone per day. A 140-block mixed base (100 stone + 40 sheet metal) sits at a 17.14 percent blended rate and needs 5,143 stone plus 1,372 metal fragments per day. Enter your own block counts in the calculator above for an exact figure.
Twig is protected while the Tool Cupboard holds wood, but the moment the cupboard runs out of wood, twig pieces decay completely within 1 hour. Because twig is the intentional anti-griefing tier, it gets no shelter bonus: it always decays in 1 hour once upkeep stops.
Yes. Buildings decay from the outside in, and pieces sheltered under a roof decay much slower. The default server setting decay.upkeep_inside_decay_scale is 0.1, which makes indoor pieces decay at 10 percent of the normal rate, so they last about 10 times longer. Server admins can change this value, so treat indoor times as approximate.
Rust has grief protection: when a Tool Cupboard is destroyed while it still holds resources, it consumes up to 24 hours worth of upkeep, which delays the start of decay by up to a day. A locked cupboard is more likely to trigger this protection, so always put a lock on your TC.
Yes. Remaining decay time equals the full-health decay time multiplied by the current health percentage. A stone wall at 50 percent health has 5 hours x 0.50 = 2.5 hours left outdoors, and an armoured wall at 80 percent health has 12 hours x 0.80 = 9.6 hours left. Use the health slider in the calculator to see this for your base.
Upkeep is charged separately per resource: wood, stone, metal fragments, and high quality metal. The resource that runs out first sets your deadline. For example, stocking 20,000 stone and 5,000 metal fragments on a 140-block base (100 stone + 40 sheet metal) gives 3.89 days of stone but only 3.64 days of fragments, so the fragments limit you to about 3.64 days.
Place a Tool Cupboard inside your base, authorize yourself on it, and keep it stocked with the resources your base is built from: wood for twig and wood tiers, stone for stone, metal fragments for sheet metal, and high quality metal for armoured. Restocking the cupboard stops decay immediately; repair any decay damage with a hammer and the matching resource.
Yes. Upkeep covers every building piece connected to the Tool Cupboard, doors included, and each piece is charged on what it cost to build or upgrade. This calculator uses standard wall-piece costs (Twig 50 wood, Wood 200 wood, Stone 300 stone, Sheet Metal 200 metal fragments, Armoured 25 HQM). Foundations, doorframes, and stairs can cost more per piece, so verify exact numbers in game if you need full precision.
Methodology & Sources
Data verified on 8 October 2026 against current Rust sources:
- Decay times (Twig 1h, Wood 3h, Stone 5h, Sheet Metal 8h, Armoured 12h): official Facepunch wiki — wiki.facepunch.com/rust/the_tool_cupboard — cross-checked with corrosionhour.com/rust-decay-upkeep-variable (server convars decay.duration_twig=1, wood=3, stone=5, metal=8, toptier=12) and rustly.com/guides/rust-tool-cupboard-guide.
- Upkeep tax brackets (1–15 blocks at 10%, 16–65 at 15%, 66–190 at 20%, 191+ at 33.3%, progressive/blended, rounded up per resource): corrosionhour.com/rust-decay-upkeep-variable (server convars decay.bracket_N_blockcount/costfraction), cross-checked with wiki.rustclash.com/item/tool-cupboard and the worked examples on rustly.com (12-block stone starter: 3,600 stone build cost → 360/day).
- Per-piece build costs (wall standard): Twig 50 wood, Wood 200 wood, Stone 300 stone (verified), Sheet Metal 200 metal fragments (verified), Armoured 25 HQM. The stone/metal figures cross-validate against published upkeep ranges (stone 30–100, metal 20–67 per piece per day).
- Indoor decay: server convar decay.upkeep_inside_decay_scale default 0.1 → sheltered pieces decay at 10% rate. Grief protection: destroyed TC consumes up to 24h of upkeep (Facepunch wiki).
Values can change between Rust updates and server admins can override decay settings. When in doubt, confirm against your server and the in-game Tool Cupboard readout.
Free tool by NRTechStudio