Rust Decay Calculator
Estimate how long an unprotected Rust building piece has left before it decays, using its material tier and current health.
Inputs
Choose the building material tier. Full-health decay times range from 1 to 12 hours.
Enter current health from 0 to 100 using a period for decimals, for example 62.5.
Changes only the displayed/exported time unit; the underlying estimate remains the same.
Live result
Estimated decay time
3.75 hours
Equivalent to 3 h 45 min at 75% health.
Selected material
Stone
Current health
75%
Full-health decay time
5 h
Decay tick rate assumption
300
Model: full-health decay time × current health fraction = estimated time remaining.
Vanilla material reference
| Material | Full-health decay time | At current health |
|---|---|---|
| Twig | 1 h | 45 min |
| Wood | 3 h | 2 h 15 min |
| Stone | 5 h | 3 h 45 min |
| Sheet Metal | 8 h | 6 h |
| Armoured | 12 h | 9 h |
How to use this Rust decay calculator
What this calculator does
This calculator estimates the remaining decay time for one Rust building piece after upkeep protection is gone. It uses the selected material tier, the piece's current health percentage, and the standard full-health decay time for that tier. The estimate assumes the usual vanilla decay timing and a linear relationship between remaining health and remaining decay time. It does not predict the exact order in which every wall, roof, foundation, door, vehicle, or external structure in a whole base will disappear, because real decay behavior can depend on building layout, protection, exposure, item type, and server configuration.
When to use it
Use it when you find an unprotected or under-maintained building piece and want a quick time-left estimate; when deciding whether a damaged wall needs immediate repair; when comparing the practical decay resistance of Twig, Wood, Stone, Sheet Metal, and Armoured tiers at the same health level; or when testing how a server-side decay multiplier could make vanilla timing assumptions unreliable. Facepunch's official Tool Cupboard and decay guide explains that stocked upkeep prevents base decay and lists the standard full-decay times for these five building tiers.
How to calculate
- The calculator opens with a ready-to-use example: Stone at 75% health, displayed in hours. The example Excel workbook is immediately available.
- Choose Material. This sets the tier's full-health decay time: Twig 1 hour, Wood 3 hours, Stone 5 hours, Sheet Metal 8 hours, or Armoured 12 hours.
- Replace Health with the current percentage from 0 to 100. Decimals such as 62.5 are accepted. Use a period as the decimal separator; commas, scientific notation, unit text, and values outside the range are rejected instead of being silently reinterpreted.
- Choose the Decay time unit you want to read and export: hours, minutes, or seconds. The unit changes presentation only; it does not change the underlying time estimate.
- Read Estimated decay time, then use the secondary results and the material reference table to understand the assumptions. Select Download Excel to export the current validated state as a real XLSX workbook.
- Select Reset to clear the demonstration health value and calculated content. Reset intentionally does not restore the startup example; Download Excel is disabled until a complete valid health value is entered again.
Input guide
Material is required and is a fixed-choice text value. Choose one of the five building tiers. Example: Stone. A stronger tier raises the full-health timer and therefore raises the estimate at the same health percentage. A common mistake is assuming the tier covers every Rust entity; this calculator follows the building-material timing model rather than separate vehicle or deployable decay variables.
Health is required and accepts a plain decimal percentage from 0 through 100. Example: 75. Higher health means more time remains under the linear model; 0% returns zero time and 100% returns the full-health timer. Do not paste “75%”, “1e2”, or comma-decimal text into the field. The percent sign is already provided by the interface.
Decay time unit is required and accepts Hours, Minutes, or Seconds. Example: Hours. Changing it converts the same canonical duration rather than changing the material or health. This matters when comparing values: 3.75 hours, 225 minutes, and 13,500 seconds are identical durations, not three different decay outcomes.
Output guide
Estimated decay time is the primary estimate. It is driven by Material and Health, then expressed in the selected Decay time unit. Zero means the entered structure has no remaining health under this simplified model. A larger result means more time remains before the piece reaches zero health if unprotected decay proceeds at the assumed rate. Selected material repeats the tier used in the calculation. Current health shows the validated percentage. Full-health decay time is the vanilla tier baseline before health scaling. Decay tick rate assumption shows 300, matching the reference model's stated default assumption; server settings can make actual decay differ. The summary pills show the same canonical material, health, time, and tick-rate values in a compact form. The Vanilla material reference table lists each material's full-health baseline and the estimated time at the current health percentage; every “At current health” value is driven by the same Health input.
Worked example
The startup example selects Stone, 75% health, and Hours. Stone's full-health decay time is 5 hours. Convert 75% to the health fraction 0.75, then calculate 5 × 0.75 = 3.75 hours. That is exactly 3 hours 45 minutes, which is the first-open result and the value exported to the workbook. The table applies the same 75% health fraction across the other tiers, so Wood becomes 2.25 hours and Armoured becomes 9 hours.
Learn more
Server configuration can materially change decay behavior. Facepunch's official console command reference documents the decay.scale multiplier and other upkeep-related variables. For base-layout vocabulary used when discussing where decay may progress through a structure, the official Rust building terminology guide provides useful context.
How the decay estimate works
The model starts with the standard time for a full-health material tier, then scales that duration by current health. In compact form: remaining time = full-health decay time × health ÷ 100. The relationship is linear, so halving the health halves the estimated time remaining. This makes scenario comparisons easy: at 50% health, Twig is 30 minutes, Wood is 1.5 hours, Stone is 2.5 hours, Sheet Metal is 4 hours, and Armoured is 6 hours.
The Tool Cupboard is the more important operational control. According to the official Rust wiki, a base with the required upkeep resources is protected from decay; once a needed resource runs out, affected building materials begin to decay. The same source also notes that different materials can begin decaying independently when only one upkeep resource is exhausted. That is why this calculator should be treated as a time-left estimate for a selected material piece, not as a complete base-destruction simulator.
Common interpretation mistakes
- Confusing building decay with vehicle decay. Some vehicles have their own server variables and different indoor/outdoor timers. Do not use a building-material estimate as an exact minicopter timer.
- Ignoring modded-server settings. A server administrator can change decay multipliers. The displayed 300 tick-rate assumption and vanilla material times are reference conditions, not a guarantee for every community server.
- Assuming full-base simultaneity. Bases can decay from exposed outer portions inward, so several pieces with the same tier and health may not necessarily reach zero at the same wall-clock moment.
- Treating converted units as separate scenarios. Hours, minutes, and seconds are only different representations of the same duration.
Use the estimate for planning and learning, then verify actual protection time and upkeep status in the Tool Cupboard on the server you are playing.