The Rust decay calculator above answers the two questions that actually decide whether a base is standing when you log back in: how long a block of a given tier survives without upkeep, and how much resource that base burns per day to stop decay starting in the first place. Both are simple arithmetic once you have the right constants, and the constants are the part people get wrong.
Arb Digital builds free calculators that name their sources and keep the volatile numbers editable. Rust is patched constantly, and any page that hard-codes a decay table will be wrong within a wipe or two. Every figure here is loaded as a default and can be overwritten, so the tool stays useful after the next update changes something.
Which Version These Figures Come From
The decay durations are the ones published by Facepunch on the tool cupboard, decay and building privilege page of the official Rust wiki: twig decays in 1 hour, wood in 3, stone in 5, sheet metal in 8 and armoured in 12, each measured from the point at which the matching resource runs out in the tool cupboard. That is the live documentation on the Rust wiki as of this writing in 2026.
The hitpoint values loaded alongside them — 10 for twig, 250 for wood, 500 for stone, 1,000 for sheet metal and 2,000 for armoured — are the figures the community consistently reports for building blocks, and they are what the calculator assumes unless you change them. They are not quoted from the official wiki, which is why both boxes are editable and why you should confirm them against the item panel in your own game. Facepunch changes building values between updates, sometimes without announcement, and a figure that was right last wipe may not be right this one.
The upkeep percentage is deliberately left as an input. Upkeep scales with how many building blocks a base contains, and the bracket thresholds have been adjusted several times. The tool cupboard in-game displays the actual cost for your specific base, and that number beats any table published anywhere.
How to Use It
- Pick the tier of the block you care about — usually the weakest tier in the base, because that is what fails first.
- Confirm the hitpoints and decay duration against your own game if you want precision.
- Set the current health if the block has already taken damage; decay runs against whatever is left.
- Enter how many hours the base will sit unprotected, counting from when the cupboard empties rather than from when you logged off.
- Fill in the build cost, the upkeep percentage from your cupboard, and the resources stocked, to see how many days of protection you have paid for.
The Formula and How It Is Calculated
Decay is applied at a steady rate, which makes the arithmetic linear. Decay per hour = maximum hitpoints / full decay time, and time until destroyed = current hitpoints / decay per hour.
Work the defaults. A stone block has 500 hitpoints and a 5 hour decay time, so it loses 500 / 5 = 100 hitpoints an hour. At full health it survives 500 / 100 = 5 hours. After 3 hours unprotected it is on 500 − 300 = 200 hitpoints, or 40% health, with 2 hours left.
Because the rate is proportional to the maximum, the countdown scales with health directly. A stone block already down to 50% health has 250 hitpoints and 2.5 hours, not 5. That is worth internalising: raiders who partially damage a wall and leave have also halved how long it survives your next absence.
Upkeep runs on a separate clock. Upkeep per day = total build cost × upkeep percentage, and days of protection = resources stocked / upkeep per day. A 5,000 resource base at 20% costs 1,000 a day, so 10,000 stocked lasts 10 days. Only when that runs out does the decay countdown above begin.
Why the Weakest Tier Sets the Deadline
A base is not one decay timer, it is one per block, and they run in parallel from the moment upkeep lapses. A stone base with a few leftover twig foundations from the original placement loses those twig pieces in an hour, while the stone itself lasts five. If any of those twig pieces was load-bearing, or was holding a door frame, the practical failure comes at the one hour mark rather than the five hour one.
The same applies across upgrades. Sheet metal doors on a stone base give you eight hours on the doors and five on the walls, so the walls fail first and the doors become irrelevant. Working out a base's real survival time means finding the shortest timer among the pieces that matter, not the longest, and that is usually the tier you forgot to upgrade.
Mixed tiers also complicate upkeep, because each tier draws its own resource. A base that is mostly stone with sheet metal doors consumes both stone and metal fragments, and running out of either starts decay on that part of the structure while the rest is fine. Checking the cupboard for the resource closest to empty, rather than the total, is the practical version of this.
Turning Hours Into a Real Schedule
The number people actually want is not "5 hours" but "will this be here when I get back". That is a calendar question, and the cupboard stock is what answers it. Ten days of upkeep means the decay timer never starts within a normal week away; two days of upkeep means the base is gone before a weekend is over.
Wipe schedules cut the other way. On a server wiping weekly there is no point stocking a month of upkeep, since the resources are destroyed with everything else. Matching stock to the time remaining in the wipe is the efficient play, and our days until date calculator and countdown timer are handy for tracking that against a wipe schedule. The add and subtract time calculator converts a decay window into a wall-clock time if you want to know the exact hour a block reaches zero.
What This Calculator Does Not Model
Four things sit outside it. The first is raid damage, which is applied instantly rather than over time and does not follow this rate at all. What raid damage does do is shorten the decay countdown, because it lowers the current health the timer runs against.
The second is the difference between block decay and deployable decay. Boxes, furnaces, sleeping bags and external walls each have their own behaviour and their own protection rules, and this page models building blocks only.
The third is server configuration. Modded and community servers routinely change decay scale, upkeep cost and even disable decay outright. If you play on anything other than an official server, the server's own settings override every number here.
The fourth is anything about how to play. This is arithmetic on published constants, in the same spirit as our K/D ratio calculator and eDPI calculator, which likewise compute a figure rather than telling anyone what to do with it. The Minecraft circle generator is the same idea in a different game.
Arb Digital designs and builds free interactive calculators that state their sources, show their arithmetic and earn links because they are genuinely useful. Browse what we have already published, or tell us what your audience keeps searching for.
Browse the Free Tools Hub Talk to Arb DigitalCommon Mistakes to Avoid
- Timing decay from when you logged off. The countdown starts when the cupboard runs dry, which may be days later.
- Reading the longest timer as the base's survival time. Every block decays on its own clock, and the weakest tier is what fails first.
- Assuming a full-health countdown on a damaged block. Decay runs against current health, so a half-damaged wall has half the time.
- Checking only the total in the cupboard. Each tier draws its own resource, and running out of one starts decay on that part of the base alone.
- Trusting a decay table found online without checking the version. These values change between updates, and a page that cannot be edited is a page that is eventually wrong.
Related Free Tools From Arb Digital
For the calendar side, use the days until date calculator, the countdown timer and the add and subtract time calculator. For other gaming arithmetic, see the K/D ratio calculator, the eDPI calculator and the Minecraft circle generator. The percentage calculator covers the upkeep percentage arithmetic on its own. Everything else is on the free online tools hub.
Frequently Asked Questions
Five hours from full health, according to the decay durations published on the official Rust wiki. Twig takes 1 hour, wood 3, stone 5, sheet metal 8 and armoured 12, each measured from the point the matching resource runs out in the tool cupboard.
When the tool cupboard runs out of the resource that tier needs, not when you log off. A base with ten days of upkeep stocked has not started decaying at all, however long you have been away.
Its maximum hitpoints divided by its full decay time. A stone block on the commonly cited 500 hitpoints with a 5 hour decay time loses 100 hitpoints an hour, so after 3 hours unprotected it sits at 200.
Not faster, but it dies sooner. The rate stays the same, so a block already at half health has half the time remaining. Raid damage that is left unrepaired therefore shortens the countdown on your next absence.
As a percentage of the base's total resource cost per 24 hours, with the percentage set by how many building blocks the base contains. The brackets have changed between updates, so read the figure directly off your own tool cupboard rather than from any published table.
Because they change. The decay durations here are quoted from the official wiki, and the hitpoints are the values the community consistently reports, but Facepunch adjusts building values between updates. Both fields stay editable so the tool survives a patch.
Often not. Decay scale, upkeep cost and whether decay runs at all are all server settings, and community servers change them routinely. On anything other than an official server, the server configuration overrides everything on this page.
The weakest tier among the pieces that matter. A stone base with leftover twig foundations loses those in an hour while the stone lasts five, so the practical failure point is the twig, not the stone.
This page is an unofficial fan tool. It is not affiliated with or endorsed by Facepunch Studios. Decay durations are quoted from the official Rust wiki and hitpoint values are commonly cited community figures; all of them change between game updates and are overridden by server configuration, so confirm anything important in your own game.
