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Compute balance and what a Run costs

Building a model in Hydrata is free. You pay to run simulations, and you are told the price before the Run starts.

This page explains the mechanism and the words. The numbers live in one place only, so they cannot go stale here: see hydrata.com/plans for the current free threshold, the daily cap, the credit pack sizes and the refusal ceiling.

What is charged, and when

Action Charged?
Creating a project, uploading terrain, drawing inputs No
Importing global terrain, merging terrains, building a design storm No
Clicking Build on a Scenario No. Build makes the mesh and the package and dispatches nothing
Dispatching a Run Yes, at the quote, at the moment it is dispatched

So the charge lands once, when a Run leaves for compute, and never before.

The quote

A quote is the exact amount a Run will be charged. It is not a range, a band or an estimate that gets trued up afterwards: the quote is the charge, to the cent.

Hydrata can only quote a Run once the mesh exists, because the price is computed from the built mesh's triangle count and the simulated duration. Those two are frozen at build time, so the quote cannot drift between the moment you read it and the moment you click Run. That is why the sequence is Build first, look at the quote, then Run.

Before a build, the Build tooltips show the predicted triangle count instead. That is a size signal, not a price.

The free band

A Run whose quote comes out at or below a threshold costs nothing and does not touch your balance. Most small models, including the Getting Started tutorial, land here.

Free Runs are capped per day, per account, counted over a UTC day. Once the cap is used, a free Run is refused until the following day rather than being charged. The run strip tells you that before you click, and the Billing tab shows the threshold, the cap, and how many you have used today.

Compute balance and credit packs

Compute balance is a prepaid, dollar-denominated balance that priced Runs debit. It belongs to an account, which is either your personal account or an organisation's. An organisation's balance is shared by all of its members and has one manager.

A credit pack is a one-time purchase that adds its value to the compute balance. Packs and balances are dollars end to end: there is no separate token or point unit to convert, and credits do not expire.

The Private models subscription covers privacy, not compute. A Run costs the same either way.

Credit back when a Run produces nothing

If a Run ends without producing results, its charge is returned to your compute balance in full, automatically. That covers both a Run that failed and a Run you cancelled yourself.

Two details worth knowing:

  • Credit back is a ledger entry, not a card refund. The money returns to your compute balance, ready for the next Run, and nothing moves at your bank.
  • If a Run did publish results, it is not credited back. You keep the results and you pay for them. A Run cannot both be refunded and leave you its output.

A failed build is never charged in the first place, because the charge happens at dispatch and a build never gets that far.

A retry is a new Run

Retrying after a failure creates a fresh Run, which is quoted and charged on its own. The failed Run's credit back and the retry's charge are separate entries. So a retry is not free, but you are not paying twice for the failure either.

When a Run is refused

Situation What happens
Your balance does not cover the quote The Run is refused. The price on the run strip turns into a button that opens your Billing tab, so you can top up and come straight back
Today's free Runs are used and the quote is free The Run is refused until tomorrow
The quote is above the automatic ceiling The Run is refused rather than charged, and you are offered a custom quote

In every case the refusal happens before any compute is dispatched, so a refused Run costs nothing.

Where to look in the app

Open the Account panel and select the Billing tab. It always shows your own account, whoever owns the project you are looking at, and it holds:

  • your compute balance, and the credit packs you can buy
  • Free runs today, with the cap and the threshold in words
  • Subscription, for the privacy plan
  • Recent activity: the most recent ledger entries, each with its date, whether it was a charge or a credit back, its amount, and a link to the project it came from

The words, in one place

Term Meaning
Quote The exact amount a Run is charged. Available once the Scenario is built, debited at dispatch
Compute balance An account's prepaid, dollar-denominated balance that priced Runs debit
Credit pack A one-time purchase that adds its value to the compute balance
Credit back The automatic return of a Run's charge to the balance when the Run produces no results. A ledger entry, not a card refund
Free band The zero-priced case: a quote at or below the threshold costs nothing, bounded by a per-account daily cap
Account The billing entity that holds the balance. Personal, or an organisation's and shared by its members