Designing a Roblox Game Economy: Faucets, Sinks, and Inflation

Every Roblox game with a currency has an economy, whether or not anyone designed it. In the games where nobody did, you can usually tell within a week of launch. Veteran players sit on balances so large that nothing in the shop is worth looking at. New players see prices built for those veterans and conclude the game is not for them. The team responds by adding a more expensive item, which fixes nothing for a fortnight.

I have designed and rebalanced economies for simulators, tycoons, and tower defense games, and the problems are remarkably consistent. This guide is the framework I use, written for designers and developers who want an economy that still makes sense six months after launch.

Faucets and Sinks

The simplest useful model of a game economy has two parts. Faucets are every place currency enters the game. Sinks are every place it leaves. The total amount of currency held by your players is whatever has come out of the faucets minus whatever has gone down the sinks.

Before pricing a single item, list both sides for each currency. A typical simulator looks something like this:

• Faucets: core loop rewards, quest and achievement rewards, daily and timed rewards, offline earnings, promo codes, event rewards, and Developer Product purchases.
• Sinks: upgrades, eggs or crates, consumable boosts, zone unlocks, rebirths, crafting and fusing, cosmetics, and trading fees.

The list on its own is revealing. Teams often discover that they have seven faucets and two sinks, and that both sinks are one-off purchases a player stops caring about after the first week. That economy will inflate, and the list told you so before a single player joined.

Why Inflation Is the Default

Roblox progression systems almost always increase income. Better pets collect more, upgraded droppers produce more, rebirth multipliers multiply everything. That is the point of progression, and players enjoy it. But it means the rate of currency entering the economy rises the longer someone plays, while most sinks are priced at a fixed point in time.

Once a player's income outruns everything there is to buy, three things happen. Prices stop meaning anything to them, so rewards stop feeling like rewards. Any new content has to be priced for those players, which locks out newcomers. And in a game with trading, prices quoted in the soft currency explode, because there is so much of it around.

The fix is not to stop income growing. It is to make sure there are always sinks that scale with it, so that at every stage of progression there is something worth spending on.

Choosing Your Currencies

One currency doing every job is the most common structural mistake I see. If the same coins pay for early upgrades, late-game eggs, and premium cosmetics, you cannot tune one without breaking the others. Give each currency a single job:

• A soft currency earned constantly through the core loop. It is allowed to inflate with progression, because its prices scale with it.
• A scarce currency earned slowly, from harder content or specific sources, and spent on things that should hold their value.
• Optionally, an event currency that exists only for a limited event and expires or converts afterwards, so events never permanently inflate the main economy.

Separating currencies by source is a powerful tool. In Hero Pets Simulator, coins and diamonds drop from visually distinct villain types. Coins flow freely and inflate with playtime; diamonds stay scarce and hold their value, which keeps the late-game progression ladder meaningful. Players understand the difference immediately because they can see which enemies drop which.

Two cautions. Every currency is a concept a new player has to learn, so three is plenty for most games. And be very careful about selling an inflating currency for Robux. If a coin bundle that bought ten upgrades at launch buys one upgrade a month later, the players who paid for it feel cheated, and they are not wrong. What Robux buys should hold its value. Our monetisation guide covers which purchase types suit which items.

Cost Curves and Income Curves

Most Roblox progression uses exponential costs: each upgrade costs a fixed multiple of the last. Income usually grows exponentially too, because each upgrade adds a percentage. The number that matters is not either curve on its own but the ratio between them: how long a player has to play to afford the next upgrade.

If costs and income grow at the same rate, every upgrade takes the same time forever and progression feels flat. If costs grow slightly faster, each upgrade takes a little longer than the last, which is the gentle slope you want. If costs grow much faster, players hit a wall. You can see which you have built in about a minute, before a single player does:

-- Paste into the Studio command bar to check pacing before anyone plays
local BASE_COST = 50
local COST_GROWTH = 1.15       -- each upgrade costs 15% more than the last
local BASE_INCOME = 5          -- coins per second at level 1
local INCOME_GROWTH = 1.10     -- each upgrade adds 10% income

local function upgradeCost(level: number): number
    return math.floor(BASE_COST * COST_GROWTH ^ (level - 1))
end

local function incomePerSecond(level: number): number
    return BASE_INCOME * INCOME_GROWTH ^ (level - 1)
end

local totalSeconds = 0
for level = 1, 60 do
    local secondsToAfford = upgradeCost(level) / incomePerSecond(level)
    totalSeconds += secondsToAfford
    if level % 10 == 0 then
        print(string.format("Level %d: next upgrade takes %.0fs, %.1f hours played in total",
            level, secondsToAfford, totalSeconds / 3600))
    end
end

With those numbers, the 60th upgrade takes a little over two minutes and the whole ladder takes under an hour of play. That is far too short for a game you want people returning to for weeks. Change COST_GROWTH to 1.22 and the same ladder takes around twelve and a half hours, with the final upgrade taking over an hour on its own. Somewhere between those is right for your game, and you can find it in Studio rather than by watching your retention charts.

This simulation is deliberately simple. It assumes a player does nothing but grind one income source, which no real player does. But it catches the gross errors, such as a ladder that ends in an afternoon or a wall at level 40, which are exactly the errors that are expensive to fix after launch. Benchmark the totals against real session lengths: if your typical player plays forty minutes a day, a ladder that takes eight hours lasts them under two weeks.

Sinks Players Actually Enjoy

A sink that feels like a tax is a sink players resent. Repair costs, death penalties, and fees on everything drain currency, but they make the game feel stingy. The best sinks feel like progress:

• Rebirths and prestige. Reset currency and upgrades in exchange for a permanent multiplier. This is the most powerful sink in the simulator genre, because it removes everything at once and players choose it eagerly. Remember that the multiplier is also a faucet: price each rebirth so it scales with the income it unlocks.
• Fusing and crafting. Combine several lower items into one better one. This removes items as well as currency, which matters enormously in games with trading.
• Consumable boosts. Temporary multipliers are spent and gone, and they make the next session feel faster.
• Cosmetics. Status and self-expression are effectively unlimited sinks that never affect balance.
• Unlocks with ongoing value. A new zone with better rewards is a sink that pays the player back, which is why players are happy to save up for it.

A good test for any sink: would a player choose to spend here if they had the currency and nothing forced them? If yes, it is a healthy sink. If players only spend because the game makes them, expect complaints and churn.

Very Big Numbers

Simulators in particular reach enormous values. Hero Pets Simulator's rank ladder spans a million-fold range, from Bronze at 1x to Hamburger at 1,000,000x, and the numbers built on top of it grow accordingly. Two things go wrong at that scale.

The first is precision. Luau numbers are double-precision floats, which represent whole numbers exactly only up to 2^53, about nine quadrillion. Beyond that, adding a small reward to a huge balance can do nothing at all. If your economy is heading there, either design rebirths that reset balances well before the limit, or store large values in a different form, such as a mantissa and exponent pair.

The second is readability. A balance of 48213958201734 is not information; it is noise. Abbreviate consistently everywhere numbers appear:

-- ReplicatedStorage/Shared/FormatNumber (ModuleScript)
local SUFFIXES = { "", "K", "M", "B", "T", "Qa", "Qi", "Sx", "Sp", "Oc", "No", "Dc" }

local function abbreviate(value: number): string
    if value < 1000 then
        return tostring(math.floor(value))
    end
    local tier = math.min(math.floor(math.log10(value) / 3), #SUFFIXES - 1)
    local scaled = value / 10 ^ (tier * 3)
    return string.format("%.2f%s", scaled, SUFFIXES[tier + 1])
end

-- abbreviate(1234)           --> "1.23K"
-- abbreviate(48213958201734) --> "48.21T"

return abbreviate

Trading Changes Everything

The moment players can trade, your economy stops being a set of separate single-player economies and becomes one shared market. That has three consequences designers need to plan for.

Scarcity becomes the source of value, so it has to be enforced on the server. Any roll that decides what a player receives is a decision the client must never make. Duplication bugs become economy-wide events: a duplicated item does not stay with one player, it spreads through trades within hours, and its value is permanently gone. And every item sink becomes more important, because items that never leave the game slowly lose value as supply grows.

The game design side of this is choosing what can be traded and building sinks that remove items, such as fusing, as well as currency. The engineering side is atomic, server-authoritative trades and session-locked saves, covered in our DataStore best practices guide and our anti-exploit guide. Our World Defenders TD case study describes running a trading economy across years of live updates.

Instrument the Economy

Everything above gets you a reasonable starting point. Real players will then do things your spreadsheet did not predict, and the only way to see it is to measure. Roblox's economy analytics let you log every source and sink, and the Creator Hub then charts currency flowing in and out over time, broken down by transaction type and item.

The practical trick is to route every currency change through one module, so logging is impossible to forget:

-- ServerScriptService/Modules/Wallet (ModuleScript)
local AnalyticsService = game:GetService("AnalyticsService")
local PlayerData = require(script.Parent.PlayerData)

local Wallet = {}

function Wallet.earn(player: Player, currency: string, amount: number,
        transactionType: Enum.AnalyticsEconomyTransactionType, itemSku: string?)
    local balances = PlayerData.get(player).currencies
    balances[currency] += amount
    AnalyticsService:LogEconomyEvent(player, Enum.AnalyticsEconomyFlowType.Source,
        currency, amount, balances[currency], transactionType.Name, itemSku)
end

function Wallet.spend(player: Player, currency: string, amount: number,
        transactionType: Enum.AnalyticsEconomyTransactionType, itemSku: string?): boolean
    local balances = PlayerData.get(player).currencies
    if balances[currency] < amount then
        return false
    end
    balances[currency] -= amount
    -- Sinks are logged with a positive amount; the dashboard shows the direction
    AnalyticsService:LogEconomyEvent(player, Enum.AnalyticsEconomyFlowType.Sink,
        currency, amount, balances[currency], transactionType.Name, itemSku)
    return true
end

return Wallet

-- Usage:
-- Wallet.earn(player, "coins", 50, Enum.AnalyticsEconomyTransactionType.Gameplay)
-- Wallet.spend(player, "coins", 800, Enum.AnalyticsEconomyTransactionType.Shop, "SpeedUpgrade")

Economy events are only sent from the server and only from published games, so you will not see them while testing in Studio. Once they are flowing, watch three things: whether sources consistently outpace sinks for a currency, how average balances change as players progress, and which items absorb the most currency. A sink nobody uses is a price or value problem. A balance that climbs without limit is a missing sink.

Common Economy Mistakes

Pricing for launch day. Prices that feel right in week one are wrong by week four, because balances have grown. Price with the whole progression curve in mind, and keep prices in configuration rather than code so you can adjust them without a rebuild.

Fixing inflation by taking currency away. Halving everyone's balance, or quietly nerfing a faucet players rely on, feels like theft to the people affected, however justified it is. Add new sinks or a new tier of content instead. Players accept new things to spend on far more readily than losing what they have.

No late-game sinks. The players with the most currency are your most engaged players. If there is nothing for them to spend on, they are the first to get bored, and the next to leave.

Events that print money. A generous event is fun for a weekend and leaves a permanent bulge in the economy. Use an event currency, or make event rewards items rather than main currency.

Designing the economy before the loop. An economy distributes rewards for doing something. If that something is not fun, the economy cannot rescue it. Our game loop design guide covers how to get the core loop right first.

An Economy Is a Living System

No economy is finished at launch. The goal before launch is a structure that can be tuned: clear currency roles, sinks that scale with income, a pacing curve you have actually simulated, and analytics that tell you what players are really doing. After launch, the job is watching those numbers and adjusting gently and often, rather than rarely and drastically.

Economy design is a core part of the design work we do at Santoz Studios, from first pacing simulations through to post-launch tuning. If you are planning an economy, or trying to rescue one that has run away from you, you can hire our Roblox team for exactly that work. Tell us about your game; we would be glad to take a look at the numbers.