Pokémon

Pokemon GO Fans Unveil Mechanics Behind Egg Tier Hatch Rates

Pokemon GO fans have come together on Silph Road and deciphered how egg hatching rates work in-game.
Pokemon GO fans have come together on Silph Road and deciphered how egg hatching rates work in-game. / Niantic Labs

Pokemon GO fans have come together on Silph Road and deciphered how egg hatching rates work in-game.

Players have been requesting Egg Transparency over Pokemon GO's loot box-like egg hatching system for over a year now—to which Niantic Labs finally responded. The developer added an egg tier function in April 2021 which sorted the Pokemon within each egg group into one of five Rarity Tiers. Exciting as this was, however, the Silph Road wasn't about to let this go at face value.

A large group of "Silph Researchers" came together to work out the rates behind the Rarity Tiers and their discoveries shed a whole new light on egg hatching in Pokemon GO. With approximately 1500 eggs hatched, the team was able to get a better grasp of each rate.

We've broken down Silph Experiment #046 for trainers eager to take advantage of hatching.

There were three main findings uncovered as a result of the experiment. We now understand that the Rarity Tiers are less set in stone and more in a permanent state of flux according to changes in each egg's hatching pool. Key findings, according to the Silph Road, are:

  1. Rarity Tiers likely represent a range of hatch probabilities, not relative weights.
  2. Species within a single Rarity Tier can have different hatch rates.
  3. Species may change Rarity Tiers when other species are added or removed from the egg pool.

So, what does this mean for the average trainer?

Rates of Hatching according to Rarity Tier
Rates of Hatching according to Rarity Tier / Silph Road, Niantic Labs

Pokemon GO Fans Unveil Mechanics Behind Egg Tier Hatch Rates

Key Findings Explained

First, hatch rates according to this experiment are less about how often a Pokemon will hatch and more about how much of a chance they have per egg. Think of it like shiny hunting. The odds are that one out of every 500 encounters is a shiny Pokemon. However, that doesn't mean trainers are guaranteed to pull a shiny after every 500 spawns. Each individual encounter instead carries a 500:1—0.2%—chance of appearing as shiny.

Second, not every Pokemon in each tier is created equal—that is to say that individuals in each tier do not share a single rate. For example, a tier-one Pokemon such as Vullaby has an over 20% chance of hatching as opposed to another tier one like Absol who sits around 15%. This same divide is seen in tier three Golurk at just under 15% and its tier-sibling Litleo at around 5%.

The Effect of Changing Pokemon in an Egg Group on Rarity Tiers
The Effect of Changing Pokemon in an Egg Group on Rarity Tiers / Silph Road, Niantic Labs

The third finding is much more complex. According to the data uncovered by Silph researchers, adding or removing certain Pokemon to an egg group has an effect on the Rarity Tier of others within that group. As certain species are added, previous members get shifted around, often resulting in a decrease in hatch rate and possibly the removal of an entire tier.

"In the first image, Drowzee and Voltorb appear in the most common group (Tier 1) alongside two regional Pokémon. When the number of regional Pokémon is increased to three or more — as shown in the second image," the team explains, "Tier 1 is eliminated completely, shifting Drowzee and Voltorb to Tier 2."

This, according to the team, proves that Rarity Tiers more directly correlate to probabilities rather than specific weights.

The team closed their study with a soft warning to trainers looking to heavily rely on the Egg Transparency feature. In their experience, it's more of an estimate than a tried and true prediction, so trainers should take care when sorting their eggs to hatch.