Balance and economies

Why it matters

Almost every game has an economy: something players earn, spend and want more of. It might be gold, health, ammunition, time, cards in hand or experience points. If resources flow in too fast, choices stop mattering and players get bored. Too slow, and they feel stuck. Balance is the work of tuning those flows (and the strength of options) so that choices stay interesting.

The core idea: sources, sinks and stocks

Think of each resource as water in a tank.

• Sources (faucets) add to it: quest rewards, income per turn, enemies dropping coins.
• Sinks (drains) remove it: buying items, upkeep, repair costs, death penalties.
• The stock is how much the player has right now.

The net flow per turn is sources minus sinks. If the net flow is always positive, the stock grows without limit and prices become meaningless (inflation). If it is always negative, players run dry. Designers aim for a net flow that lets players afford meaningful things at a pace that matches the game's length.

gold_next_turn = gold_now + income - upkeep

Worked example: how long until the castle?

A player starts with 20 gold, earns 12 per turn and pays 4 upkeep. A castle costs 100.

• Net flow = 12 - 4 = 8 gold per turn.
• Gold needed = 100 - 20 = 80.
• Turns = 80 / 8 = 10 turns.

If playtests show 10 turns is too long, you can raise income, cut upkeep, lower the price, or add a one-off source (a quest reward). Each lever has side effects: raising income also speeds up every other purchase. That is why designers prefer to change one number at a time and re-check.

Types of balance

• Economic balance: the flow of resources over time (the example above).
• Option balance: no single strategy, weapon or character is the obvious best choice. Rock-paper-scissors is perfectly balanced because each option beats one and loses to one.
• Difficulty balance: challenge matches player skill (covered in the next lesson).
• Fairness between players: for example, first-player advantage in turn-based games.

Perfect balance is not always the goal. Some imbalance creates interest: a strong but risky option, or a character that is great on one map. What matters is that every option has a reason to be chosen.

Using spreadsheets and simulations

Designers model economies in spreadsheets or small scripts before touching the game. A simple simulation answers questions like "after 30 turns, how much gold does a careful player have?" or "can a player ever get stuck with zero gold and no way to earn more?". That last one, a dead state, is one of the worst balance bugs, and simulation catches it early.

Pure functions (same inputs, same outputs, no side effects) are ideal for this: you can call them with hundreds of combinations and compare the results.

Common mistakes

• Tuning by feel only. Write down the numbers and model them; intuition about growth curves is often wrong.
• Forgetting sinks. Many games add more and more rewards and end with players hoarding resources that have nothing to buy.
• Changing many numbers at once. You lose track of what caused the change.
• Dead states. Make sure a player at zero can always earn their way back.
• Balancing only for experts or only for beginners. Test both a careless and a careful strategy.

Quick recap

• Economies are sources, sinks and stocks; the net flow sets the pace.
• Turns to afford something = (price - current) / net flow, rounded up.
• Balance covers economies, options, difficulty and fairness; some imbalance is healthy.
• Model with small pure functions or spreadsheets, change one number at a time, and watch for dead states.

Try it

Open the Do tab and write the two economy functions a designer would use to tune the castle example.