Cosmos Era beginner guide: how to play the first three eras

The short version: buy generators to build up resources, spend resources to complete events, and finishing the events moves you into the next era. After 12 events in a run you can "rebirth" and use the singularities you earn for permanent speed-ups. The first three eras are Primordial universe, Particle era and Nuclei & atoms. Here is what to do in each, in order.

The loop in every era

Each era has its own resource, 4 generators and a series of events.

• Generators produce the era's resource automatically. Keep buying them while you can afford it. Prices keep climbing (the base prices of the 4 generators are 10, 120, 1600 and 24000, and each purchase raises the price by ×1.12, ×1.13, ×1.14 and ×1.15 respectively).
• Events are the era's milestones, and you pay resources to complete them. Each completed event raises the era's output.
• Complete every event in an era and the next era unlocks, with a global output ×1.3.

The rhythm is simple. If output feels slow, buy more generators. When you can afford the next event, complete it. Don't let resources sit idle.

Era 1: Primordial universe

• Resource: energy. Time span: from 0 seconds after the Big Bang.
• The 4 generators, in order: Quantum fluctuation, Inflaton field, Vacuum decay, Reheating.
• 7 events: Planck epoch (10⁻⁴³ s), Gravity separates (10⁻⁴³ s), Grand unification epoch (10⁻³⁶ s), Cosmic inflation (10⁻³⁶ s, space expands 10²⁶ times), End of inflation (10⁻³² s), Reheating (10⁻³² s), Electroweak symmetry breaking (10⁻¹² s, the Higgs field gives particles mass).

This is the tutorial stage. Buy Quantum fluctuation first so energy grows by itself, and complete each event as soon as you can afford it. After all 7 events you enter the Particle era.

Era 2: Particle era

• Resource: particles. Time span: 10⁻¹² seconds to 3 minutes.
• The 4 generators, in order: Quark–gluon plasma, Matter–antimatter annihilation, Hadronization, Neutrino decoupling.
• 6 events: Quark epoch, Baryon asymmetry (one extra matter particle for every billion matter–antimatter pairs), Hadron epoch (quarks are confined into protons and neutrons), Lepton epoch, Neutrino decoupling, Electron–positron annihilation.

The point of this stage is to build on the bonus from the last era. The global ×1.3 from finishing the previous era is already active, so particles grow faster than energy did.

Era 3: Nuclei & atoms

• Resource: atoms. Time span: 3 minutes to 150 million years.
• The 4 generators, in order: Proton capture, Deuteron fusion, Helium-4 synthesis, Electron capture.
• 6 events: Big Bang nucleosynthesis (about 25% of the mass becomes helium), Lithium-7 formation, Matter domination (47,000 years), Recombination (380,000 years, electrons are captured by nuclei), Cosmic microwave background (380,000 years, the universe becomes transparent), Dark ages (380,000 to 150 million years, no stars, only neutral hydrogen cooling).

The first two eras have 7 + 6 = 13 events between them, already more than the 12 you need for a rebirth. So when you finish the Particle era, you will see the "ready to rebirth" prompt for the first time.

Your first rebirth

You can rebirth after completing 12 events in a run. A rebirth collapses the universe back into a singularity:

• Reset: resources, generators, events.
• Kept: singularities, permanent upgrades, relics, achievements, records.
• Reward: singularities. Every singularity earned in total gives +5% to all output, and spending them doesn't reduce that.

When should you rebirth? When progress slows down. A good rule for beginners: if you can't afford the next generator for several minutes in a row, or the next event is a long wait away, rebirth. The bonus you get makes the next run much faster.

What to buy first

Spend singularities on permanent upgrades in "Upgrades". There are 9 in total. A good order for beginners:

1. Buy "Cosmological constant" first: all output ×1.5. One singularity buys the first level.
2. Once you have enough, buy "Whisper of entropy". It automatically buys generators for 2 eras, so you no longer click by hand.
3. To make each run start faster, buy "Memory echo", which automatically completes the first 3 events on every rebirth.

The price and cap of all 9 upgrades are listed in Rebirth and the singularity shop: what to buy first.

Offline progress and time crystals

When you close the page, the game still counts offline earnings. The base offline cap is 12 hours. To fast-forward, use time crystals: each crystal skips 1800 seconds (30 minutes). You earn 1 per 3600 seconds at base, up to a base cap of 24. For where crystals come from and how to use them, see Time crystals: how to get them and use them.

Daily goals

The game gives you 3 goals a day, drawn from 6 types: complete events, buy generators, catch encounters, use time crystals, rebirth, and read Codex cards. Saves that have never rebirthed won't be given the rebirth goal.

• Each goal you claim gives 2 time crystals, some singularities, and a draw of one science card.
• Claim all 3 goals and you get 3 more time crystals, plus output ×5 for 300 seconds.

Claim them when you pass by. You don't need to change how you play for them.

Common beginner questions

• Resources growing slowly? First check for idle resources, then check whether it's time to rebirth.
• Can't afford an event? Buy more generators first. Once output is up, the event becomes affordable.
• Don't want to keep clicking? After a rebirth, buy "Whisper of entropy" and "Causality" (which completes events automatically when you can afford them). That is close to fully idle.

(Sources: game data GAME.ERAS for the first three eras, the GAME.P parameter table, GAME.SHOP, and the in-game beginner tutorial text.)