Cosmos Era rebirth and singularity shop: what to buy first
The singularity shop has 9 permanent upgrades. Buy Cosmological constant first, then Whisper of entropy and Memory echo. Price = base price × multiplier^level.
The short answer: a beginner should buy "Cosmological constant" first, then "Whisper of entropy", then "Memory echo". Add "Vacuum discount" and "Time lattice" in the middle game. "Causality" and "Evolutionary instinct" are one-time idle helpers, so buy them as soon as you have the singularities. Below is the full data for all 9 upgrades and how to buy each.
What a rebirth does
A rebirth collapses the universe back into a singularity:
- Reset: resources, generators, events.
- Kept: singularities, permanent upgrades, relics, achievements, records.
- Every singularity earned in total gives +5% to all output. It counts what you have earned in total, so spending them doesn't reduce it.
To rebirth you need at least 12 events completed in the run. If you witness the end (the last event of the last era) before you rebirth, singularity gain is ×2. Every rebirth also refills 2 time crystals (never above the cap).
How singularities are calculated
Singularities earned on rebirth = floor(1.31 to the power of (total events this run − 12 + 3)). Witnessing the end doubles it, and choices and some cosmological constants apply further multipliers.
- Exactly 12 events: 1.31³ is about 2.25, which rounds down to 2 singularities.
- Each extra event multiplies the result by 1.31.
- So doing a few more events before you rebirth pays off fast, and more so the further you go.
The price formula
The price of level n of an upgrade = floor(base price × multiplier^n). Take "Cosmological constant" with base price 1 and multiplier 3.2: level 1 costs 1 singularity, level 2 costs 3, level 3 costs 10, level 4 costs 32, and each level after that costs about 3.2 times the previous one. Upgrades with a multiplier of 1 ("Causality", "Evolutionary instinct") don't rise in price, and have only 1 level.
The 9 upgrades at a glance
| Upgrade | Effect | Base price | Multiplier | Max level |
|---|---|---|---|---|
| Cosmological constant | All output ×1.5 | 1 | 3.2 | 60 |
| Memory echo | Automatically completes the first 3 events on each rebirth | 2 | 2.6 | 30 |
| Whisper of entropy | Automatically buys generators for 2 eras | 3 | 4.5 | 6 |
| Causality | Automatically completes events when affordable | 30 | 1 | 1 |
| Vacuum discount | Event cost ×0.6 | 5 | 4 | 12 |
| Evolutionary inertia | The previous era gives a stronger bonus to the next | 8 | 5 | 8 |
| Time lattice | Time crystal output +50%, cap +12 | 4 | 3.5 | 8 |
| Offline resonance | Offline earnings +10%, offline cap +8 hours | 2 | 2.5 | 5 |
| Evolutionary instinct | Automatically unlocks affordable evolution tree nodes | 2000 | 1 | 1 |
How to buy each one
Cosmological constant: the best first step. Its base price is just 1, every level multiplies all output, and it goes up to level 60. In the early game, buy everything you can afford each run.
Memory echo: automatically completes the first 3 events on each rebirth, and every level saves more opening time. Base price 2, multiplier 2.6, max level 30.
Whisper of entropy: automatically buys generators for 2 eras, so you stop clicking by hand. Max level 6. It is almost an idle switch, and beginners should buy it in the first run once they have 3 singularities.
Causality: completes events automatically when you can afford them. Base price 30, only 1 level. Buy it when you reach 30 singularities, and after that you can mostly ignore events.
Vacuum discount: event cost ×0.6. Base price 5, multiplier 4. The pricier events get in the middle game, the more it is worth.
Evolutionary inertia: makes the previous era's bonus to the next era stronger. Base price 8, multiplier 5. Buy it late, when there are many eras and the bonus chain is long.
Time lattice: time crystal output +50%, cap +12. Base price 4, multiplier 3.5. Players who often fast-forward with crystals should buy it first. Details are in Time crystals: how to get them and use them.
Offline resonance: offline earnings +10%, offline cap +8 hours. Base price 2, multiplier 2.5, max level 5. Buy it if you often close the page and let the game run.
Evolutionary instinct: automatically unlocks affordable evolution tree nodes. Base price 2000, only 1 level, a price you only reach late in the game. Once you own it, you barely need to unlock tree nodes by hand.
When to rebirth
- If you can't afford the next generator or event for several minutes, rebirth.
- At exactly 12 events a rebirth gives only 2 singularities. Each extra event multiplies the gain by 1.31, so a few more events are worth it.
- Rebirth after witnessing the end for ×2 singularities. This is the most rewarding rebirth.
Buying too much has a cost
- "Memory echo" automatically completes the first few events on rebirth. Some endings need you to make a choice in a specific era (for example "The trilobites' civilization" and "The microbes won"). If Memory echo skips those eras, you can't make the choice. The game's ending hints say you can lower it in "Upgrades".
- Capped upgrades can be ignored once maxed: "Whisper of entropy" tops out at level 6, "Offline resonance" at 5, "Time lattice" and "Evolutionary inertia" at 8. Keep your singularities for upgrades that can still level up.
- The one-time "Causality" and "Evolutionary instinct" never rise in price. Buy them once you can afford them. There is no reason to wait.
A suggested route
- Run 1: buy "Cosmological constant" level 1 or 2, and at 3 singularities buy level 1 of "Whisper of entropy".
- Runs 2 to 5: keep adding "Cosmological constant" and add "Memory echo".
- Mid game: pick "Vacuum discount", "Time lattice" and "Offline resonance" to match how you play.
- At 30 singularities: buy "Causality".
- At 2000 singularities: buy "Evolutionary instinct".
(Sources: the names, descriptions, base, mul and max of the 9 items in GAME.SHOP, the shopCost price formula, the in-game rebirth page text, and the GAME.P parameter table.)
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