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

Time Dimensions is another type of Dimension that is unlocked after Eternity. Time Dimensions generate Time Shards, which when there is enough Time Shards that has reached the requirement for a free tickspeed upgrade, it will generate a free tickspeed upgrade that doesn't apply to the regular tickspeed cost, and isn't lost until Eternity. Time Shards are either only lost on eternity (includes dilating time), or when entering an Eternity Challenge.

Normally, each tickspeed upgrade requires 33% more than the previous, unless you have Time Study 171 (only 25% more), starting at 1 time shard.

Dim # Price (EP) Price Increase (multiplicative) Starting price (>e308) Price Increase (>e308) Starting price (>e1300) Price Increase (>e1300)
1 1 3 4.25e422 4.5 5.15e1631 6.6
2 5 9 6.26e365 13.5 7.31e1491 19.8
3 100 27 9.89e345 40.5 1.66e1435 59.4
4 1000 81 3.41e336 121.5 2.07e1405 178.2
5 1e2350 24300
6 1e2650 72900
7 1e3000 218700
8 1e3350 656100

Each upgrade of a TD will quadruple its power, and will cost EP. Cost of a TD will increase for every purchase (like all the other dimensions).

When the cost of a TD exceeds 1.8e308, its price increase multiplies by 1.5 and its price recalculates for the new scaling. When it exceeds 1e1300, the scaling changes again the same way as before, with price increase going to 2.2 times the initial value. These apply retroactively and do not count for Time Dimensions 5-8.

Time Dimensions 5-8 are locked until you buy one of the Time Studies after the Time Dilation time study, which are only unlocked after you are able to get enough TT produced from Tachyon Particles (1e15 dilated time upgrade).