Scratch cards

A scratch card is an instant-win game in which a player buys a fixed-price ticket and reveals concealed symbols to find out whether it carries a prize. The result exists before the reveal; scratching displays it.

That sequence — outcome first, reveal second — holds in both formats the term covers, but the two produce the outcome in different ways, and the difference decides what the quoted odds describe.

Physical and digital scratch cards

A printed lottery scratchcard comes from a finite print run. Prizes are allocated across the whole run at production, so the odds quoted on the card express the ratio of prize-bearing tickets to total tickets.

The UK National Lottery publishes those figures per game:

• Game 1422, £300 000 Birthday, a £2 card, ran to 50 177 640 tickets at overall odds of 1 in 3.89, with a prize pool worth 68.00% of the run’s face value.
• Game 1384, £100 000 Teal, a £1 card, ran to 44 046 180 tickets at 1 in 4.06 and 62.00%.

Two properties follow from the finite pool. Prizes deplete as they are claimed, so a ticket bought late draws from a distribution that has already lost some of its top tiers. And the quoted odds cover any prize at all, almost all of them at the bottom: game 1422 holds seven prizes of £300 000 against more than 10 million at £2 or £5.

A digital scratch card has no finite pool unless the game rules create one. Each round is an independent event resolved when the stake is placed, with no shared inventory of winners being drawn down.

When the outcome is determined

The sequence in a digital round is fixed. The player commits a stake, the server draws from the random number generator, the value is mapped through the paytable to a prize tier or a loss, and only then does the client render the reveal. Dragging across the panels changes nothing: the symbols were assigned before the first was cleared.

British rules make that explicit rather than leaving it to game design. RTS 7C prohibits designs expected to mislead a customer about the likelihood of results, including substituting a losing outcome with a near-miss. Where a game uses a pre-determined layout, the winning spots may not move during play except as the rules provide. Since 17 January 2025 the standards have also barred features that give an illusion of control, such as turbo and slam stops (RTS 14E), and autoplay across online gaming products (RTS 8A).

RNG, paytable and prize distribution

Three components decide what a digital scratch card returns, and they are usually collapsed into one figure.

The random number generator produces the raw outcome. Under RTS 7A it must be acceptably random: uniformly distributed, unpredictable without full knowledge of algorithm and seed, non-repeating and non-synchronising between instances, with any scaling preserving those properties. Adaptive behaviour — altering outcome probabilities during play — is not permitted.

The paytable maps that output onto prize tiers, fixing both the value of each tier and how often it occurs. Two cards advertising the same return can therefore behave nothing alike: one pays small amounts frequently, the other holds most of its return in a tier almost nobody reaches. That distribution is the game’s volatility, and the share of rounds returning anything is its hit frequency.

Return to player is the theoretical share of total stakes a game returns over an indefinitely long run — a property of the paytable rather than a forecast for a session. House edge is its complement.

RTP is also a disclosure obligation. Before a customer commits to gamble, RTS 3C requires the operator to make available how the game works, how prizes are allocated, and the house edge, the RTP percentage or the probability of winning events. Live RTP must then be monitored against the figure the game was tested to, with tolerances derived from volatility and the volume of play.

Scratch cards and slots

Both are RNG games governed by a paytable, so the differences are structural rather than mathematical.

A scratch card round has one decision and one outcome: the stake is placed, the result is drawn, the reveal displays it. A slot spin can branch into free spins, bonus rounds and multipliers, so a stake does not always resolve in one step, and paylines add a second dimension to a win.

The interaction differs in the same direction. A slot’s reels stop under RNG control once the spin is initiated, while a scratch card’s reveal sits under the player’s finger and has no bearing on the result. Neither accepts input that changes the outcome after the stake. Both sit inside the broader instant win category.

Certification and player information

Games and RNGs supplied to the British market are tested by an approved test house before release. The Gambling Commission’s list as of 2 March 2026 runs to fourteen entities, among them BMM Testlabs, eCOGRA, Gaming Associates Europe and six Gaming Laboratories International companies. Each holds BS EN ISO/IEC 17025 accreditation, and appointing one approved for the relevant scope is the licensee’s responsibility.

Testing covers game maths, the artwork and rules as displayed to players, theoretical RTP verified through simulation and manual testing, and the scaling that converts raw RNG output into game outcomes. Reports record the game name, its RTP, the software number and the digital signature.

Where a scratch card runs outside that framework, on a crypto-native operator, a provably fair scheme substitutes cryptographic verification for laboratory testing: the server publishes a hashed seed before the round, the player adds a client seed, and both are revealed afterwards so the result can be recomputed. It shows that one outcome was not altered after the fact; it does not assess the RNG or the paytable, which is what an accredited test house does.

FAQ

Bottom line

A scratch card is a reveal mechanic attached to a result that already exists — printed into a finite run months earlier, or drawn from an RNG at the moment of the stake. What the game returns is decided by the paytable behind it; what a player can check sits in the disclosure and certification around it. The scratching bears on neither.