Roblox has three DevEx rates now. One constant won't cut it.

For years every DevEx calculator, spreadsheet and in-game earnings panel I saw did the same thing:

local DEVEX_RATE = 0.0035

That was fine while there was one rate. Since June 2026 there are three, and they apply to the same balance at the same time. If your game shows creators or group members what their Robux are worth, a single constant is now wrong in both directions.

Here's what changed and how I ended up modelling it.

The three rates

Rate	USD per earned Robux	Applies to
Legacy	$0.0035	Robux you already held before Sep 5, 2025
Standard	$0.0038	Robux earned since then
U.S. 18+	$0.0054	Certain sales to US players who verified they're 18+

The standard rate went up on September 5, 2025. Roblox didn't convert old balances at the new rate, though. Anything you held before that date stays at $0.0035, and it cashes out first.

The 18+ rate showed up on June 8, 2026. It only covers developer products, passes, subscriptions and private servers, bought by US players who verified their age, in an experience that meets Roblox's character rules (no R6 avatars). It's a second rate running next to the standard one. It doesn't replace it.

So a real creator balance is often a mix of all three.

Mixed balances

Say someone has 75,000 earned Robux. 20,000 were sitting there before September 2025, 50,000 came in since, and 5,000 came from qualifying 18+ purchases.

With one constant at the new rate you'd tell them $285. With the old one, $262.50. The real number is neither:

local total =
    20000 * 0.0035 -- legacy:    $70
    + 50000 * 0.0038 -- standard: $190
    + 5000 * 0.0054 -- us18:      $27
-- $287

The difference looks small at this size. For a group paying out a few million Robux a quarter it isn't.

Rounding

Roblox pays in USD, so I round to the cent at the end, not per part. Floats make that slightly more interesting than it sounds. 12,345 Robux at $0.0038 is 46.911, so you show $46.91. Going the other way, $100 needs math.ceil(100 / 0.0038) = 26,316 Robux. 26,315 gives 99.997, which rounds to $100.00 on screen but is still under $100 gross.

I don't know exactly how Roblox rounds on its end, so I treat these as gross estimates and say so in the UI.

The 30,000 minimum

You need 30,000 earned Robux for a first cashout. That's $114 at the standard rate. A check is trivial, but it's worth showing players how far they are from it rather than just a dollar figure.

A module instead of a constant

I got tired of retyping this, so I put the rates, the history and the arithmetic into one ModuleScript. No HttpService, no yielding, just a table and five functions:

local DevExRates = require(ReplicatedStorage.DevExRates)

DevExRates.robuxToUsd(100000) --> 380 (standard)
DevExRates.robuxToUsd(30000, "us18") --> 162
DevExRates.usdToRobux(100) --> 26316
DevExRates.rateOn("2024-01-15") --> 0.0035
DevExRates.meetsMinimum(28500) --> false

DevExRates.mixedBalanceUsd({ legacy = 20000, standard = 50000, us18 = 5000 })
--> 287

rateOn returns the standard rate in force on a given date, which is handy if you store historical earnings and want to show what they were worth at the time. It skips the 18+ tier on purpose, since that's a parallel rate and not a change to the standard one.

The code and the JSON behind it are on GitHub: supertj/devex-rates. Code is MIT, data is CC BY 4.0. There's a check script in CI that fails if the numbers in the Luau file drift from the JSON, so the two can't quietly disagree.

Keeping it current

The part that actually breaks things is Roblox changing the rate and nobody updating the constant. I re-check the rates against Roblox's docs at least every 45 days and update the repo when anything moves. The full history with sources is on LootTally's DevEx rates page, which is where the data comes from.

If you only need a one-off number and don't want to touch code, there's also a DevEx calculator that handles the mixed-balance case.

Things I'm still not sure about

• How Roblox handles the 10am PT cutoff on September 5, 2025 for Robux that landed that morning. The module treats the whole day as the new rate.
• Whether there'll be more tiers. The 18+ rate reads like a first step, not a final shape.

If you've run into either of these with real payouts, I'd like to hear how it went.