Idle Game Calculator
The math that runs every incremental game — geometric upgrade costs, doubling time, prestige payback — computed exactly, live, as you slide.
The Three Curves of Every Idle Game
Strip the cookies, mines and spaceships away and every incremental game is three formulas in a trench coat. The first is the geometric cost curve: each copy of a building multiplies its price by a fixed factor m — the industry classic is 1.15. Total spend on n copies is the geometric series c(mⁿ−1)/(m−1), and inverting it with a logarithm answers the question every player actually has: how many can I afford right now? That is exactly what the first panel computes — and it is the same 1.15 curve running inside vygam's own Bakery Tycoon, Mining Idle and Space Colony Idle, so you can check the numbers against a live game.
The second curve is exponential income growth, best understood through doubling time. The exact answer is ln 2 ÷ ln(1+r); the folk shortcut — divide 72 by the percentage — is astonishingly close in the range idle games live in, and the second panel shows both so you can watch the shortcut drift as rates climb. The third is the prestige trade: give up everything for a permanent multiplier. Its worth reduces to one number — how fast the boosted income re-earns what you abandoned — and the third panel turns your bonus and run length into a payback time and a plain verdict. Together the three panels are the honest skeleton of a genre built to feel like magic.
How to Use It
Idle Math Habits
Four rules of thumb, each of which is really one of the formulas above wearing work clothes.
Judge runs by doubling time, not digits
A number that doubles every nine minutes is growing equally fast at 1 thousand and 1 trillion — the screen just makes the later doublings look heroic. If progress feels slow, measure the doubling time; only a genuine slowdown there means your build has stalled.
The 50th copy costs ~900× the first
At 1.15×, prices cross three orders of magnitude by copy 50 — which is why idle games hand out production multipliers at milestones. Buying past a wall rarely works; growing income under it always does.
Prestige early beats prestige perfect
Payback time shrinks as the bonus grows, but waiting has a cost too: everything earned while you hesitate is earned at the slow rate. If the payback panel shows minutes against a run of hours, the reset already won — take it.
Respect the offline cap
Well-designed idle games cap offline earnings (ours use four hours) so that walking away forever is never optimal. The corollary: check-ins beat marathons, because each visit converts capped offline income into upgrades that compound while you are gone.
FAQ
Is the idle game calculator free?
Yes — the calculator on vygam is completely free, with no download and no sign-up. All three panels update instantly as you move the sliders.
Why do idle game upgrades get so expensive?
Because costs grow geometrically: each purchase multiplies the price by a fixed factor, typically 1.10–1.20. At the classic 1.15×, the 50th copy of a building costs about 900 times the first — and the total spent follows the geometric series c(mⁿ−1)/(m−1), which this calculator inverts to tell you exactly how many copies your budget affords.
What is the rule of 72?
A mental shortcut for doubling time: divide 72 by the growth rate in percent. Income growing 8% per minute doubles in roughly 72÷8 = 9 minutes. The exact answer is ln(2)/ln(1+r), and the calculator shows both so you can see the shortcut's small error — it is most accurate near 8%.
When should I prestige?
When the reset pays for itself quickly. If prestige multiplies your income by (1+g), the time to re-earn everything you gave up is your current total divided by the new, faster income. The calculator computes that payback time; the folk rule of resetting when your multiplier would at least double is simply the point where payback becomes clearly worthwhile.
Does buying in bulk change the math?
No — the geometric series already is the bulk price. Buying n copies one by one or all at once costs the same c(mⁿ−1)/(m−1) unless the game offers an explicit bulk discount. What the max-affordable formula tells you is where that series crosses your budget.
Why does my income feel slow right after a prestige?
Because exponential curves look flat at the start — doubling from a small base is invisible, doubling from a large base is spectacular, yet both take the same time at the same growth rate. Judge a run by its doubling time, not by the size of the numbers on screen.
Do vygam's own idle games use these formulas?
Yes — Bakery Tycoon, Mining Idle and Space Colony Idle all price their buildings on the 1.15× geometric curve this calculator defaults to. Load one of them beside this page and the affordability numbers line up exactly.