1 - How the villagers are triggered
A hostile within range keeps the villagers panicking, and panic checks for a golem every 100 ticks with only 3 villagers needed. This is what every farm design uses.
2 - The cells
3 is the minimum. Extra villagers help a little, because a spawn only needs 3 of them to have forgotten the last golem.
Cells have to be more than 10 blocks apart so the villagers do not count each other, and far enough that one cell's golem is not within 16 blocks of the other cell's villagers.
3 - How fast each golem is gone
100 health at 4 damage every 10 ticks is 12.5 seconds in lava, plus the drop into it
Each try picks a random column within 8 blocks of the villager and looks from 6 above to 6 below for a solid block with room over it. 10 tries a call, so 100% of calls land with this much of the 17 x 17 area usable.
Output
328iron an hourWhat the cell needs
- Every villager slept within the last day (24000 ticks). No bed they can use means no golems after the first day, which is the usual reason a farm stops.
- The hostile has to stay in range and in sight. Glass is fine, it is not solid to the villager's eyes.
- The golem lands on a solid block with the two blocks above it empty (water at its feet is allowed), and its 1.4 by 2.7 body must fit, so a one block wide slot is not enough.
- It cannot land on glass, panes, leaves, ice, cobwebs, cactus, glowstone, sea lanterns, beacons, TNT or conduits, and not on a non-solid block such as a slab's open half or a carpet over air.
- A golem alive within 16 blocks resets the wait, so kill it fast or let water carry it out of range first.
How villagers spawn iron golems
A villager wants a golem when it has slept in the last in-game day and has not seen a golem within 16 blocks in the last 599 ticks. When enough villagers in a 10 block box want one at the same moment, the game makes ten attempts to place a golem within 8 blocks, and if one lands every villager in the box forgets about golems for 599 ticks. That wait is the whole economy of an iron farm.
There are two ways the attempt gets made. Villagers that gossip try it and need 5 willing villagers, but each villager gossips at most once a minute, so that path is slow. Villagers that are panicking try it every 100 ticks and need only 3, which is why every farm design parks a zombie next to three villagers: five seconds after the last golem's wait expires, the next one appears. The ceiling is therefore 600 ticks a golem, 30 seconds, 120 an hour per cell.
Killing the golem is where real farms lose rate. Each villager's golem sensor runs once every 200 ticks, and if the golem is still alive within 16 blocks when it runs, that villager's wait restarts from 599. A lava blade takes about 15 seconds to kill a 100 health golem, so most of the time at least one sensor fires first and the cell averages about 44 seconds a golem. Pushing the golem out of range with water before it dies avoids that, which is what the better designs do.
Reading the calculator
The output is a tick by tick run of those rules for an hour, averaged over two dozen runs with random sensor timings, not a formula. The removal time is the one input you have to estimate: how long from the golem appearing until it is either dead or more than 16 blocks from the villagers. The spawnable share is for farms with a small or oddly shaped platform; a full platform is 100 percent and a quarter platform still catches most calls because of the ten tries. Iron is counted at the loot table's 3 to 5 ingots, 4 on average, with a poppy or two on the side.
Frequently Asked Questions
How much iron does an iron farm make per hour?
A single cell of three scared villagers tops out at one golem every 30 seconds, 120 an hour, which is 480 iron an hour on the 3 to 5 ingot drop. Real single-cell farms land nearer 330 because a golem dying in lava takes about 15 seconds and a villager whose sensor fires in that time waits a further 30 seconds. Each extra cell adds the same again, as long as the cells are more than 10 blocks apart.
How many villagers do you need for an iron farm?
Three, if a zombie or other hostile keeps them scared, because panicking villagers try for a golem every 100 ticks and need 3 willing villagers within 10 blocks. Without a hostile the spawn only happens when two villagers gossip and then needs 5 willing villagers, so the no-zombie layouts use 5 or more and are slower.
Why did my iron farm stop working?
Almost always sleep. A villager only wants a golem if it slept within the last 24000 ticks, one in-game day. If the beds got blocked, the villagers were moved away from them, or the cell never had beds the villagers can lie in, the farm runs for a day and then stops. The other common cause is a golem that survives within 16 blocks of the villagers: every sensor that sees it adds another 30 second wait.
How far does the zombie need to be from the villagers?
Within 8 blocks for a zombie, husk, drowned or zombie villager, and it has to be visible to them. Glass does not block that. Pillagers are seen from 15 blocks, evokers, illusioners and ravagers from 12, vindicators and zoglins from 10. A zombie with a name tag so it never despawns, under a roof so it does not burn, is the standard.
Where do the golems spawn?
On a random column within 8 blocks of the villager that triggers the spawn, scanned from 6 blocks above the villager to 6 below for a solid block with air (or water) over it. The golem then needs its full 1.4 wide, 2.7 tall body free and two clear blocks above its feet. The game makes 10 tries per call, so a platform that fills most of the 17 by 17 area almost never misses.
Does this work on Bedrock?
No, the numbers here are Java. Bedrock spawns golems from the village itself rather than from scared villagers, with different conditions, and its constants are not readable from the game files, so this page does not guess at Bedrock rates.
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