You set the game up the way you wanted it. Sprinters off, loot rare, and utilities left
running for what you were sure was three months of grace. Then on the fourth morning the
lights go out, the freezer starts ticking down, and the taps run for one last day before
they cough and stop. Nothing is broken. You typed 90 into a field that counts in hours.
Project Zomboid power and water shutoff, at a glance
| Situation | Grid dies on | What to do about it |
|---|---|---|
| Typed 90, meant three months of grace | day 4 (2026-07-12) | The field is hours. 90 cuts the grid on day four, not month three — this is the trap. |
| Actually wants three months of grace | day 91 (2026-10-07) | Enter 2160, not 90. That is 90 days expressed in the hours the field actually reads. |
| Wants a tight one-week survival test | day 8 (2026-07-16) | Enter 168. This is the setting for a short, deliberately harsh run. |
These are direct outputs of the sandbox's own hours-based countdown, computed with this site's shutoff planner — not a modelled estimate. Enter your own value in the planner below to see your run's date.
What the two fields actually mean
In the sandbox screen, under Advanced Zombie Options → Time Until Power Shut Off and the matching water field, the number is a count of in-game hours. It is not days, and the interface never says which unit it is using. The two numbers are independent: you can leave the water on long after the grid dies, which is what most long-haul settings end up doing.
Two consequences follow, and they are the reason this trips up so many runs:
90is not ninety days. It is ninety hours: three full days elapse and the cut lands during day four.- The value you probably meant is
2160. Ninety days, multiplied by twenty-four.
The other thing worth knowing before you commit: this is a start-of-run decision. Editing the value mid-save through the sandbox options does not retroactively rewind a shutoff that has already fired, so it is worth getting right the first time.
Convert it before you start the run
Put your numbers in and the planner below tells you the in-game day the utilities die, the calendar date it lands on, and roughly how much real playtime that buys you at the default day length. The last row runs the sum backwards: give it the number of days you wanted and it returns the value to paste into both sandbox fields.
Power & water shutoff planner (Build 42)
- Power cuts out
- day 4 2026-07-12 · 3d 18h survived · ~1.5 h of play
- Water cuts out
- day 4 2026-07-12 · 3d 18h survived · ~1.5 h of play
- To get the duration you wanted, enter
- 2160 in both sandbox fields (90 days × 24)
Heads up: at this setting the grid dies on day 4, not in 90 days.
Assumes the sandbox field is read as hours, which is what Build 41/42 actually does. Real-time estimate assumes the default Day Length of 1 hour.
The URL updates as you type, so a settings combination you like can be pasted straight into a thread or a server description and it will open with your numbers already filled in.
Numbers worth stealing
If you do not want to think about it, these are the values that map to the run lengths people usually have in mind. All of them assume the field is being read as hours.
| Intent | Enter | Grid dies on |
|---|---|---|
| One week of comfort | 168 | day 8 |
| Two weeks | 336 | day 15 |
| One month | 720 | day 31 |
| Three months | 2160 | day 91 |
| Six months | 4320 | day 181 |
| Effectively never | 999999 | day 41667 |
A shutoff on day 31 is the setting that produces the classic arc: enough time to clear a neighbourhood and stock a freezer, then a hard pivot to preservation right when your character has become comfortable. Day 8 is a survival scenario. Day 91 is a base-building scenario.
Plan for the day it goes out
Whatever number you land on, the day itself is the same problem every time:
- Freezer contents are on a clock from the moment the power dies. Anything you cannot eat or preserve within a couple of days is lost, so the last stable week is the week to be curing, drying, and canning.
- Fill everything that holds water before the taps stop. Rain collector barrels need a roof and time to fill; they are not a same-day answer.
- A generator only moves the deadline. It runs on fuel you have to find, and fuel in cans degrades. It is a way to keep one room cold, not a way to keep the lights on.
If you are running an interior farm or animals through the transition, the shutoff date is also the date several quiet failure modes start: heat drops, water troughs stop refilling, and nothing on screen tells you why production stalled — the same silent-failure pattern that makes hens quietly stop laying worth checking on a schedule rather than waiting for a warning that never comes.
Sources
- Power Shutoff — PZwiki — describes the sandbox power/water shutoff timer and its default range
- Custom Sandbox — PZwiki — full sandbox option list, including the “Time Until Power/Water Shut Off” fields
