Pricing
Run all 46 engines, the dyno and the spec editor for nothing. Pro unlocks the builder. Builder AI builds it from a sentence.
$0
No account needed to run anything.
$5 / month
Billed $60 a year
$20$12 / month
Billed $144 a year
Trusted worldwide
Free, Builder Pro, Builder AI
Every real engine runs free. Builder Pro opens the wizard and the garage. Builder AI adds a chat over the same engine: type one, change it, ask about it.
| What you can do | Free | Builder Pro | Builder AI |
|---|---|---|---|
| All 46 real engines | |||
| Dyno, P–V trace, spec editor, share links | |||
| Build your own: any family, layout, fuel and size | |||
| Tune the breathing: intake, cam, spark curve, mixture, carburettor | |||
| Garage: save the engines you build | |||
| AI chat: type an engine, change it, ask about it | |||
| Saved conversations | |||
| Early access to new features | |||
| Time to your first engine | ~10 min | ~10 s |
You type the engine and hear it. You type one change and hear that. A displacement sweep or a cam comparison costs a sentence per variant, where the wizard costs nine steps.
Ask what lobe separation does, or why compression dropped when it fitted the turbo. You get the answer in your engine's own numbers, and the build carries on.
Everything you can run today: every real engine in the roster, the spec editor, the dyno, the P–V trace, sharing, and saving engines other people share. The advanced piston specs ask for a free sign-in. Only the builder is Pro.
Yes, any time, from the billing portal under your account menu. You keep Pro until the end of the period you paid for, and we charge nothing after that.
Email hello@realenginesimulator.com within fourteen days of a first purchase, with the payment date, the invoice number and your reason. The terms have the rest.
Builder Pro is the builder you drive by hand: every family, layout, fuel, size, breathing and induction, and a garage to keep what you build. Builder AI adds the AI builder — describe the engine in a sentence and it takes shape — with every conversation saved. It is the better start if you are new to engines: ask it what a lobe separation angle does or why a long runner fills at low rpm, and it explains as it builds. Everything in Builder Pro is in Builder AI.
Yes, in one click from this page or from the AI builder. You pay only the difference for the rest of the period you are in, on the same billing date, and the AI builder opens at once. Moving back to Builder Pro is done from the billing portal and takes effect when the period ends.
Cards and the wallets Polar supports. Polar works out tax at checkout for where you live; the price shown is before it.
Nothing is deleted. The builder and your garage close until you subscribe again, and then everything you saved is back where you left it. Share links you already sent keep working for everyone.