Rollover, in full
Only the top tier normally rolls. Lower tiers are paid out every draw, so the money that carries over is the jackpot allocation that found no winner. Each roll stacks the unclaimed pot on top of the next draw's fresh contribution, which is why a jackpot can climb quietly for weeks and then jump sharply once the headline number starts pulling in extra ticket sales.
Most games cap the run. Some set a ceiling on the jackpot amount, others limit the number of consecutive rolls, and once the limit is reached the next draw is a must-be-won draw. If that draw produces no top-tier ticket, the jackpot rolls down instead of forward and is shared out across the lower winning tiers, which briefly makes small matches pay far more than usual. Where the cap sits differs by game and is set out in each operator's published rules.
A rollover changes the prize, never the odds. The matrix is the same, the draw is the same, and a single UK Lotto line faces the same 45,057,474 combinations in each round at a capped jackpot as it does at a starting one. What a big roll does change is the crowd. More tickets sold means more chance that a winning line is held by more than one person, so the expected share of the prize is smaller than the headline suggests.
- Lottery mechanics
- Jackpot roll, Rollover jackpot
A worked example
A game with a £2 million starting jackpot goes unwon four draws in a row. If each draw adds roughly £2 million of fresh jackpot allocation, the advertised figure runs about £2m, £4m, £6m, £8m, £10m. Nothing about the draw has changed across those five nights. The same six balls come out of the same 59 in each round, and any single line still sits at 1 in 22,528,738 for the night.
See also
Where it comes up on this site
Rollover: frequently asked
No. Bigger prize, same matrix. If anything the heavy sales a big roll attracts make a shared jackpot more likely, so the expected payout per winning line goes down rather than up.
The draw at the end of a capped run, where the jackpot cannot carry forward again. With no top-tier ticket the money rolls down into the lower tiers instead, which is why match-three and match-four prizes occasionally spike.