Gamemath

A statistical reading room
Australia · en-AU

Contents

02 / The denominator

Return to which stakes?

RTP is a ratio. Before treating it as an answer, ask whether it is a design average or a measurement from a defined set of plays.

RTP = return to player

Meaning before prediction

Two separated transparent layers above an unmarked paper surface
Conceptual still life — not a ratio or scale. A design average and a measured sample are different things.

Designed over many plays

A theoretical RTP is the long-run share of stakes a game is designed to return in prizes. A stated 90% is not a claim that a particular $1 stake gives back 90 cents, or that a particular session returns 90% of what was put in.

Australian context VGCCC, Understanding poker machines (updated 1 June 2026): theoretical return is not what someone should expect from a single session.

90%Hypothetical design figure: $0.90 in expected prizes per $1 staked across the game's probability model; not a per-play payout or an Australian minimum.

“Long-run” describes how the figure is constructed, not a deadline after which any particular player is made whole. A short sequence may be far above or below it.

Measured over chosen plays

Observed (actual) RTP is calculated from prizes paid divided by stakes across a specified set of plays. State the set—such as the entries in a hypothetical ledger—because changing which plays are included changes the measured ratio.

Technical reference — Great Britain. UK Gambling Commission, Key terms relating to live RTP performance monitoring of games (updated 28 January 2021) separates theoretical and actual RTP; How to calculate RTP (updated 25 January 2021) uses generated win and turnover to calculate observed RTP. This technical definition is not a statement of Australian regulation.

prizes
÷ stakesFor the same defined set of plays. This is an observed ratio, not the game's theoretical setting.

What about the remainder?

In a simplified fixed-stake model that counts all prizes paid against all stakes placed, a hypothetical theoretical RTP of 90% leaves an expected 10% of stakes not returned as prizes. This is a conditional arithmetic complement, not a promise of a 10% loss in any session and not an Australian machine specification.