Sudoku Variants

Every variant playable free, with generated puzzles, hints and lessons:

• Thermometer Sudoku — Along each thermometer, digits increase from the bulb.
• Arrow Sudoku — Digits on each arrow sum to the number in its circle.
• Killer Sudoku — Cage digits are distinct and add up to the small number.
• Kropki Sudoku — Black dot: one digit is double the other.
• Whisper Sudoku — Along a green line, neighbouring digits differ by at least 5 on a 9×9; on other sizes, by half the digit range rounded up (3 on a 6×6).
• Zipper Sudoku — On a zipper, digits an equal distance from the centre sum to the centre digit.
• Renban Sudoku — Each magenta line holds a set of consecutive digits, in any order.
• Palindrome Sudoku — Each grey line reads the same forwards and backwards.
• Between Lines Sudoku — Digits on a between line fall strictly between the two circled ends.
• Entropic Sudoku — On a peach line, every three in a row include one low (1-3), one middle (4-6) and one high (7-9).
• Odd / Even Sudoku — Circles are odd digits, squares are even digits.
• XV Sudoku — X pairs sum to 10, V pairs sum to 5.
• Greater Than Sudoku — Each chevron points from the larger digit to the smaller one.
• Consecutive Sudoku — A bar marks neighbours that are consecutive.
• Anti-Knight Sudoku — Cells a knight’s move apart cannot hold the same digit.
• Anti-King Sudoku — Cells touching diagonally cannot hold the same digit.
• Non-Consecutive Sudoku — Orthogonally touching cells cannot hold consecutive digits.
• Diagonal Sudoku — Both main diagonals also contain 1-9.
• Windoku Sudoku — Each of the four shaded windows also contains 1-9.
• Sandwich Sudoku — Each outside clue is the sum of the digits sitting between the 1 and the 9 in that row or column.
• Slow Thermometer Sudoku — Along each slow thermometer, digits never decrease from the bulb.
• Double Arrow Sudoku — On a double arrow, the two circled ends sum to the same total as the digits between them.
• Lockout Line Sudoku — A lockout line’s diamond ends differ by at least 4, and every digit between them falls outside that range.
• Region Sum Line Sudoku — On a blue line, the digits in each region the line passes through add up to the same total.
• Min / Max Sudoku — A cell marked min is smaller than all four of its orthogonal neighbours; max is larger than all four.
• Quadruple Sudoku — Each circle at a corner lists digits that must all appear in the four cells around it.
• Extra Region Sudoku — The shaded region also contains 1-9, exactly once each.
• Clone Sudoku — The shaded shapes hold identical digits, cell for cell.
• Little Killer Sudoku — Each outside clue is the sum of the digits along its diagonal.
• Disjoint Groups Sudoku — Cells in the same position within their box cannot repeat — the nine top-left cells hold 1-9, and so on.
• Negative Constraint Sudoku — Every kropki dot is given.
• Dutch Whisper Sudoku — Along an orange line, neighbouring digits differ by at least 4.
• Modular Line Sudoku — On a cyan line, every three in a row include one digit from each of 147, 258 and 369.
• X-Sums Sudoku — Each outside clue is the sum of the first X digits in from that side, where X is the first of them.
• Skyscrapers Sudoku — Each outside clue counts the digits visible from that side, where a larger digit hides every smaller one behind it.
• Average Arrow Sudoku — The circled digit is the mean of the digits on its arrow.
• Parity Line Sudoku — Along a parity line, adjacent digits alternate between odd and even.
• Nabner Line Sudoku — No two digits on a Nabner line are the same or consecutive, wherever they sit on the line.
• 10 Line Sudoku — Each 10 line splits into one or more runs of adjacent cells, with no overlap, each summing to 10.
• Anti-Factor Line Sudoku — On an anti-factor line of length L, no digit other than 1 is a factor or multiple of L, and the digits sum to a multiple of L.
• Equal-Sum Line Sudoku — Every marked segment of an equal-sum line has the same total.
• Calcudoku — a number puzzle on a Latin square: digits in each cage reach its clue with + − × or ÷.