Polytopia Star Economy Calculator
Use this tool to decide whether buying an economy upgrade now will pay off before the match ends.
Tip: If break-even happens after the final turn, the upgrade is usually too late unless it unlocks a tactical advantage.
What this Polytopia calculator helps you do
In The Battle of Polytopia, stars are your tempo. Every unit, tech, and city upgrade competes for the same currency, so timing matters more than raw income. This calculator is built to answer one practical question: Should I invest in economy right now, or keep spending on army and pressure?
Instead of guessing, you can project your star total at the end of the match in two scenarios:
- Baseline: you do not buy the upgrade.
- Invest: you pay the upgrade cost now and gain extra stars each turn.
How the calculator works
1) Remaining turns
The first step is simple: remaining turns = final turn − current turn. Economy investments are strongest when made early, because they have more turns to pay back.
2) Baseline projection (no upgrade)
Baseline end stars are estimated as:
- Current stored stars
- + (current stars per turn − planned military spend per turn) × remaining turns
This gives you a rough budget if you keep your current strategy.
3) Investment projection (buy upgrade now)
If you buy the upgrade now, your stored stars drop immediately by the upgrade cost, but your income increases every turn:
- Current stored stars − upgrade cost
- + (current stars per turn + upgrade gain − planned military spend) × remaining turns
Comparing this with the baseline gives your expected net gain or loss.
4) Break-even turn
Break-even turns are estimated by upgrade cost ÷ upgrade gain, rounded up. If break-even happens after the game ends, the investment is usually inefficient in pure economy terms.
When to invest vs when to fight
Invest in economy when:
- You have enough turns left to break even.
- You can defend safely while waiting for returns.
- The upgrade opens additional scaling plays (ports, trade chains, or city growth).
Prioritize military when:
- Enemy pressure is immediate.
- You can capture cities soon and gain stars through expansion instead.
- The map is close to decided and long-term payoff no longer matters.
Example decision
Suppose you are on turn 10 of a 30-turn match with 15 stored stars, 12 stars per turn, and you are considering a 10-star upgrade that adds +3 stars per turn. You also expect to spend around 4 stars per turn on units.
- Break-even time is about 4 turns.
- Because 20 turns remain, the upgrade has plenty of time to return value.
- If your front line is stable, investing is often correct.
If this same decision appears on turn 26, the answer flips: there are too few turns left for the investment to matter.
Practical strategy tips for better results
- Recalculate after every major city capture. New cities can change income math fast.
- Track spending discipline. High military upkeep can erase economic gains.
- Use break-even as a filter, not a rule. Tactical map control can justify a suboptimal economy line.
- Plan two turns ahead. If an upgrade delays a critical defense, skip it.
- Value flexibility. Sometimes keeping stars banked is better than forcing a rigid build path.
FAQ
Is this an official Polytopia formula?
No. This is a practical planning model for economy timing. It is intentionally simple so you can make fast decisions mid-game.
Why include military spend in the calculator?
Because stars you plan to spend every turn are not truly available for tech and scaling. Including that estimate gives a more realistic projection.
Can I use this for Perfection or Domination?
Yes, as a budgeting tool. Just set the final turn for your mode and update assumptions as your board state changes.