Suomeksi

Every Building in Island Tycoon

Base cost, base income and every milestone multiplier — the real numbers from the game's own balance file, not estimates.

The 12 buildings

Base cost is what the very first copy costs. Base income is what that one copy produces per second, before any multiplier. Payback is base cost ÷ base income — how long a single, un-multiplied copy takes to earn back its own price. It is not a buying rule by itself (milestones change the math fast, see below), but it is a fair measure of how "expensive" a building's opening tier feels.

"#" is also the unlock order. A building reveals in the shop once you own at least one of the previous one — or, if you'd rather skip ahead, once your all-time earnings pass 40% of its own base cost.

District notes

⚓ Harbor — Fishing Hut is the fastest payback in the game and always the first thing you buy. Mega-Port sits at the opposite end, a late-game building in the same district as the cheapest one in the game.

🏪 Market Square — Market Stall and Bakery both pay back in under two and a half minutes; this district carries most of the opening minutes of a run.

🏙️ Downtown — the biggest district at four buildings, spanning Workshop's 4-minute payback to Skyscraper's 2 hours. Because it has the most buildings, it also has the most milestone upgrades to buy.

🏭 Industrial District — Factory is mid-game, Fusion Plant is a deep late-game building with a 27.8-hour payback for its first copy alone.

🛫 Airport — a single building that opens the fifth district. Its 5.4-hour payback is usually the point where offline earnings start mattering more than active tapping.

🌆 Uptown — Pinnacle Tower, alone, the last building in the game. Nobody buys it for the 2.5-day payback on a single copy; you buy it because it is the sixth district, and the sixth district is required for prestige. After that, its milestones are a long-term project.

The 15% price curve

Every building follows the same growth rule: the Nth copy costs baseCost × 1.15^(N−1). Buying in bulk is the sum of that geometric series, which is exactly what the game's "max affordable" button computes for you. In practice this means the 11th Fishing Hut costs about 61 coins, roughly 4× the base price of 15 — and the 21st costs about 245 coins, over 16× base. No building stays cheap once you start stacking it.

Milestone multipliers

There are two independent sources of multiplier per building, and they stack multiplicatively with each other.

Free milestones (automatic, no cost)

Every building type gets these the moment you own enough of it — no purchase needed:

Purchasable ×2 upgrades

The Upgrades tab sells a separate ×2 for each building at 1, 10, 25, 50 and 100 owned. The cost scales with the building's own base cost, so a Fishing Hut's cheapest upgrade is a few coins and a Pinnacle Tower's is enormous — but relative to what you're already spending on that building at that point in the game, every one of these is a strong buy the moment it's available.

Costs use the same suffixes the game shows in play: K/M/B/T, then two-letter suffixes (aa = 10¹⁵, ab = 10¹⁸, and so on).

Why milestones dominate

Own 100 of any building and buy all five of its ×2 upgrades, and each unit is producing 384× its base rate before any global bonus — ×12 from the free milestones at 25/50/100, times ×32 from five stacked ×2 upgrades. Push the same building to 400 owned and it's ×3,072. Doubling your building count from 100 to 200 only doubles output; crossing that 100-owned milestone alone multiplies it by 3.

For how to sequence all of this — buy order, when to prestige, and where to spend gems — see the strategy guide.