Cobalt Star Idle

Light 3,840 stars, let the Calculator level them, go supernova. An idle galaxy in your side panel that earns while you're away.

Cobalt Star Idle is an idle game about a procedural galaxy of 3,840 stars. You light them. A Calculator levels them for you. When the galaxy is lit, you collapse it into a Supernova and start again stronger. How it works Pulse the Sun to earn photons, light a star, and spend photons to level stars so they make more light. Your Calculator keeps leveling in the background, choosing the best-value level-ups from a scan window of nearby stars. Lighting 32 stars unlocks your first Supernova: collapse the galaxy for Dark Matter, which boosts income permanently. Every Supernova also extends your offline limit. Hypernova is a deeper second reset for later. Features • A procedural galaxy of 3,840 stars you can pan and zoom, with constellations and bonuses for finishing them • The Calculator: automatic leveling with a target you choose (best value, newest, lowest or pinned star) and bulk "level all" controls • The Attendant, which wakes at your first Supernova and plays the same actions you do at a pace you choose (Cruise, Steady, Sprint or Overdrive), including claiming rewards, buying Formulas and going Supernova • Seven permanent Formulas bought with Computation, three optional Trials with harder rules, daily quests, comets and 14 achievements • Receipts: a printable ledger of everything spent by the Calculator, the Attendant and you, with Share, copy, PNG and .txt export • Earns while you are away, at 60% rate, for 12 hours (up to 24 with Supernovas), and an optional notification when the cap is reached • Open in a new tab with Alt+Shift+O (changeable), compact to extra-large UI sizes, keyboard shortcuts, reduced-motion support, battery saver • Pause all automation with one button; undo your last save import • Free, no ads, no accounts, no purchases. Art and sound are generated inside the extension.