More about Antimatter Dimensions:
General Info: DimensionsTicksAchievements
Pre-Infinity: Soft ResetDimensional SacrificeAntimatter Galaxy
Pre-eternity: InfinityInfinity UpgradesChallengesAutobuyersBreaking InfinityInfinity DimensionsReplicanti
Post-eternity: EternityEternity MilestonesTime DimensionsTime StudiesEternity UpgradesEternity ChallengesTime Dilation
Misc: GuideTerminologyCheating

Eternity can be accessed once you reach Infinity Infinity Points.

Eternity is the 4th consecutive reset system, which resets everything except your achievements, statistics, challenge times, Infinity Challenge times, Time Dimensions, Eternity Upgrades, Time Studies, Eternity Milestones, Eternity Challenges, and Time Dilation. The things you keep can change depending on which Eternity Milestone you have reached.

What can I do now? Edit

Unlike Infinities, you can exceed Infinity IP whenever you want, and you will gain more EP as a result of doing so. The formula for EP is

EP = floor(5^(floor(log10(IP))/308-0.7)*bonuses) ~= 0.324*bonuses * IP^(1/440.65)

With no bonuses, the amount of IP needed for various amounts of EP for the purposes of early post-eternity is listed below:

EP IP Needed
1 1.8e308
2 1e349
3 1e426
4 1e481
5 1e524
6 1e559
7 1e588
8 1e614
9 1e637
10 1e657

There is a more extensive spreadsheet of IP -> EP values available here.

EP vs IP

EP and the exponent of IP needed to get them

After eternity, you are now able to buy time theorems based how far you go, and buy more upgrades which are called Time Studies costing time theorems. There are also eternity upgrades available. You also unlock a new set of dimensions, called Time Dimensions, which give you time shards which are translated to free tickspeed upgrades, and all these can cause more progression.

What's next? Edit

After reaching enough time theorems, you will be able to do Eternity Challenges, which eventually completing a lot of challenges will let you reach Infinity EP, but you will get an achievement, not a new prestige layer.

After completing EC11x5 and EC12x5 and buying at least 13,000 total time theorems, you will be able to spend 5,000 time theorems to unlock a new content called Time Dilation.