Learn · Incremental games
In an incremental game nearly everything can be bought again, and each one costs more than the last. How fast that price climbs, the cost curve, sets the pace of the whole game: when it flies, and when it stalls. Here are the first 100 purchases of the same thing, priced six ways.
Each price is the last one plus some amount. In proportion, the rises shrink as the price grows: 10 to 15 is half again, but 500 to 505 is just 1%.
Also called arithmetic, flat step
Every purchase costs the same amount more than the last. The income from what you've bought grows just as fast, so a game priced this way keeps a steady pace and never slows down.
Also called power curve, quadratic, cubic
The price follows a power of the count, here its square. It climbs much faster than linear early on, but its steps shrink in proportion, so in the long run any multiplying price overtakes it.
Prices multiply: by a little each purchase, or by a lot every ten. Gentle at first, they eventually outrun any price that adds, and most idle games price their generators this way.
Also called geometric, compound
Each purchase costs 7% more than the last, so the price doubles about every ten. Here it starts out cheaper than the linear curve, passes it around the 50th purchase, and then pulls away for good.
Also called geometric, compound
Each purchase costs 15% more, doubling the price about every five. Each new generator matters for a while and then gives way to the next tier, which is why the shop keeps growing.
Also called bought in tens, tiered price
The price holds for ten purchases, then jumps ten times higher. On average it multiplies like an exponential, but players buy in sets and aim for the next step.
The multiplier itself grows, so the climb gets steeper with every purchase.
Also called cost scaling, accelerating price
Each price is ×1.05 the last, and that multiplier grows 0.5% with every purchase. It works as a ceiling without a hard limit: past a point no realistic income keeps up, so the player turns to something else.
The same purchases on each curve, all starting at 10 coins.
| Curve | 10th | 25th | 50th | 100th | First 100 together |
|---|---|---|---|---|---|
| Linear | 55 | 130 | 255 | 505 | 25.8K |
| Polynomial | 1K | 6.25K | 25K | 100K | 3.38M |
| Exponential, ×1.07 | 18 | 51 | 275 | 8.11K | 124K |
| Exponential, ×1.15 | 35 | 286 | 9.42K | 10.2M | 78.3M |
| Stepped | 10 | 1K | 100K | 10B | 111B |
| Super-exponential | 19 | 128 | 38.5K | 40.3T | 97.9T |