How do you play Twenty One?

Read the prompt and get the rules straight. Play one short round to warm up. Chase your best score once the pattern clicks. Click to add 1, 2 or 3.

Is Twenty One free to play?

Yes. Twenty One runs in the browser for nothing: no download, no account and no sign-up. Twenty One sits on the Strategy shelf at Mondo Knows, alongside numbers and versus games.

How long does a game of Twenty One take?

2 minutes. It is rated medium, and click to add 1, 2 or 3. Your best score stays on your own device.

Does Twenty One work on a phone?

Yes. The board sizes itself to the screen, so Twenty One plays the same on a phone as on a desktop, and touch controls replace the mouse. Nothing needs installing.

Mondo Knows Games

Twenty One

Players take turns adding one, two or three. Whoever lands on 21 loses the round. Mondo plays the winning line.

Best Strategy GamesMedium2 minutesPlays on mobile

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How to play

Read the prompt and get the rules straight.
Play one short round to warm up.
Chase your best score once the pattern clicks.

Controls

Click to add 1, 2 or 3

More strategy games from Mondo

KakuroCrossword grids where the answers are sums.NonogramRead the numbers, fill the squares, reveal the picture.CalcudokuSudoku rows with arithmetic cages instead of givens.Mahjong SolitaireClear the 144-tile turtle by matching free pairs.

Questions people ask

How do you play Twenty One?: Read the prompt and get the rules straight. Play one short round to warm up. Chase your best score once the pattern clicks. Click to add 1, 2 or 3.
Is Twenty One free to play?: Yes. Twenty One runs in the browser for nothing: no download, no account and no sign-up. Twenty One sits on the Strategy shelf at Mondo Knows, alongside numbers and versus games.
How long does a game of Twenty One take?: 2 minutes. It is rated medium, and click to add 1, 2 or 3. Your best score stays on your own device.
Does Twenty One work on a phone?: Yes. The board sizes itself to the screen, so Twenty One plays the same on a phone as on a desktop, and touch controls replace the mouse. Nothing needs installing.

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Everything runs in your browser. Scores and bests are stored on your own device, not on a server.