The Calendar hole will go live in approximately 13 days. Why not try and solve it ahead of time?
Card Number Validation in all languages in chars. Achievements Cheevos Holes Languages Medals Miscellaneous All Holes 12 Days of Christmas 24 Game 99 Bottles of Beer Abundant Numbers Abundant Numbers (Long) Arabic to Roman Arithmetic Numbers Arrows Ascending Primes ASCII Table Billiards brainfuck Card Number Validation Catalan Numbers Catalan’s Constant Christmas Trees Collatz CSS Colors Cubes Day of Week DFA Simulator Diamonds Divisors Emirp Numbers Emirp Numbers (Long) Emojify Evil Numbers Evil Numbers (Long) Factorial Factorisation Farey Sequence Fibonacci Fizz Buzz Foo Fizz Buzz Bar Forsyth–Edwards Notation Fractions Game of Life Gijswijt’s Sequence Happy Numbers Happy Numbers (Long) Hexdump Hilbert Curve Intersection Inventory Sequence ISBN Jacobi Symbol Kaprekar Numbers Kolakoski Constant Kolakoski Sequence Leap Years Levenshtein Distance Leyland Numbers ln 2 Look and Say Lucky Numbers Lucky Tickets Mahjong Mandelbrot Maze Medal Tally Minesweeper Morse Decoder Morse Encoder Musical Chords N Queens Niven Numbers Niven Numbers (Long) Number Spiral Odious Numbers Odious Numbers (Long) Ordinal Numbers PalindromemordnilaP Pangram Grep Partition Numbers Pascal’s Triangle Pernicious Numbers Pernicious Numbers (Long) Poker Polyominoes Prime Numbers Prime Numbers (Long) Proximity Grid QR Decoder Quine Recamán Repeating Decimals Reverse Polish Notation Reversi Rijndael S-box Rock-paper-scissors-Spock-lizard Roman to Arabic ROT13 Rule 110 Scrambled Sort Set Seven Segment SI Units Sierpiński Triangle Smith Numbers Spelling Numbers Star Wars GPT Star Wars Opening Crawl Sudoku Sudoku (Fill-in) Ten-pin Bowling Tic-tac-toe Time Distance Tongue-twisters Topological Sort Tower of Hanoi Transpose Sentence Trinomial Triangle United States Vampire Numbers Van Eck Sequence Zeckendorf Representation Zodiac Signs γ λ π τ φ √2 𝑒 Apéry’s Constant Binary Lambda Calculus Calendar Connect Four Continued Fractions Crossword CSS Colors (Inverse) CSS Grid Ellipse Perimeters Flags Floyd-Steinberg Dithering Gray Code Decoder Gray Code Encoder Hexagonal Spiral Highly Composite Numbers Multitap Input NFA Simulator Numbrix Odd Polyomino Tiling p-adic Expansion Polygon Triangulations QR Encoder Quadratic Formula Semiprime Numbers Smooth Numbers Snake Sphenic Numbers Taxicab Numbers Turtle Tutorial All Languages ><> Assembly AWK Bash BASIC Berry brainfuck C C# C++ Civet Clojure COBOL Coconut Common Lisp Crystal D Dart Elixir Erlang F# Factor Forth Fortran Gleam Go GolfScript Groovy Haskell Hexagony J Janet Java JavaScript jq Julia K Kotlin Lua Nim OCaml Pascal Perl PHP PowerShell Prolog Python R Raku Rockstar Ruby Rust Scheme sed SQL Swift Tcl TeX V VimL Wren Zig 05AB1E ALGOL 68 APL Arturo Befunge BQN CJam CoffeeScript Egel Fennel Harbour Hare Haxe Hush Hy iogii Knight Luau Odin Picat Qore Racket Rebol Rexx Scala Squirrel Stax Uiua Umka Vala Vyxal Bytes Chars Scoring Bytes Chars Language All ><> Assembly AWK Bash BASIC Berry brainfuck C C# C++ Civet Clojure COBOL Coconut Common Lisp Crystal D Dart Elixir Erlang F# Factor Forth Fortran Gleam Go GolfScript Groovy Haskell Hexagony J Janet Java JavaScript jq Julia K Kotlin Lua Nim OCaml Pascal Perl PHP PowerShell Prolog Python R Raku Rockstar Ruby Rust Scheme sed SQL Swift Tcl TeX V VimL Wren Zig Experimental Language 05AB1E ALGOL 68 APL Arturo Befunge BQN CJam CoffeeScript Egel Fennel Harbour Hare Haxe Hush Hy iogii Knight Luau Odin Picat Qore Racket Rebol Rexx Scala Squirrel Stax Uiua Umka Vala Vyxal Hole All 12 Days of Christmas 24 Game 99 Bottles of Beer Abundant Numbers Abundant Numbers (Long) Arabic to Roman Arithmetic Numbers Arrows Ascending Primes ASCII Table Billiards brainfuck Card Number Validation Catalan Numbers Catalan’s Constant Christmas Trees Collatz CSS Colors Cubes Day of Week DFA Simulator Diamonds Divisors Emirp Numbers Emirp Numbers (Long) Emojify Evil Numbers Evil Numbers (Long) Factorial Factorisation Farey Sequence Fibonacci Fizz Buzz Foo Fizz Buzz Bar Forsyth–Edwards Notation Fractions Game of Life Gijswijt’s Sequence Happy Numbers Happy Numbers (Long) Hexdump Hilbert Curve Intersection Inventory Sequence ISBN Jacobi Symbol Kaprekar Numbers Kolakoski Constant Kolakoski Sequence Leap Years Levenshtein Distance Leyland Numbers ln 2 Look and Say Lucky Numbers Lucky Tickets Mahjong Mandelbrot Maze Medal Tally Minesweeper Morse Decoder Morse Encoder Musical Chords N Queens Niven Numbers Niven Numbers (Long) Number Spiral Odious Numbers Odious Numbers (Long) Ordinal Numbers PalindromemordnilaP Pangram Grep Partition Numbers Pascal’s Triangle Pernicious Numbers Pernicious Numbers (Long) Poker Polyominoes Prime Numbers Prime Numbers (Long) Proximity Grid QR Decoder Quine Recamán Repeating Decimals Reverse Polish Notation Reversi Rijndael S-box Rock-paper-scissors-Spock-lizard Roman to Arabic ROT13 Rule 110 Scrambled Sort Set Seven Segment SI Units Sierpiński Triangle Smith Numbers Spelling Numbers Star Wars GPT Star Wars Opening Crawl Sudoku Sudoku (Fill-in) Ten-pin Bowling Tic-tac-toe Time Distance Tongue-twisters Topological Sort Tower of Hanoi Transpose Sentence Trinomial Triangle United States Vampire Numbers Van Eck Sequence Zeckendorf Representation Zodiac Signs γ λ π τ φ √2 𝑒 Experimental Hole Apéry’s Constant Binary Lambda Calculus Calendar Connect Four Continued Fractions Crossword CSS Colors (Inverse) CSS Grid Ellipse Perimeters Flags Floyd-Steinberg Dithering Gray Code Decoder Gray Code Encoder Hexagonal Spiral Highly Composite Numbers Multitap Input NFA Simulator Numbrix Odd Polyomino Tiling p-adic Expansion Polygon Triangulations QR Encoder Quadratic Formula Semiprime Numbers Smooth Numbers Snake Sphenic Numbers Taxicab Numbers Turtle Tutorial # Golfer Points Chars Time Submitted 401st Natanaelel 🇸🇪 709 55 34ms 1 Mar 2025 402nd DialFrost 🇸🇬 709 106 11ms 13 Dec 2024 403rd GrayJoKing 🇦🇺 707 82 127ms 1 Oct 2024 404th DialFrost 🇸🇬 707 132 225ms 8 Apr 2025 405th Shanethegamer 🇺🇸 706 118 357ms 2 Oct 2024 406th MeWhenI 🇻🇦 704 115 435ms 5 Oct 2024 407th cbrt-x 703 157 139ms 1 Oct 2024 408th janlelis 702 68 60ms 1 Oct 2024 408th tatzyr 🇯🇵 702 68 45ms 23 Dec 2024 410th emgordon154 702 76 5ms 7 Jun 2025 411th Shanethegamer 🇺🇸 702 92 16ms 3 Oct 2024 411th error256 702 92 20ms 7 Oct 2024 411th thatbirdguythatuknownot 702 92 16ms 14 Oct 2024 414th sean-niemann 🇺🇸 701 82 373ms 23 Dec 2024 415th BlankSpruce 701 123 480ms 1 Oct 2024 416th mousetail 🇳🇱 701 133 149ms 3 Oct 2024 417th LukeBridges 🇬🇧 700 92 9ms 3 Oct 2024 418th emgordon154 696 134 224ms 25 Feb 2025 419th Bulmenisaurus 695 93 15ms 6 Oct 2024 419th lynn 695 93 16ms 8 Jan 2025 419th RaBa21 🇭🇺 695 93 17ms 19 Jul 2025 419th KasperKivimaeki 🇫🇮 695 93 17ms 17 days ago 419th blaztoma 🇱🇹 695 93 16ms 12 hours ago 424th Alex-x90 🇺🇸 695 124 498ms 1 Oct 2024 424th Herbert00709 🇵🇱 695 124 56ms 14 Jun 2025 426th tobeannouncd 695 159 146ms 13 Dec 2024 427th Shanethegamer 🇺🇸 693 41 3ms 4 Oct 2024 428th Shanethegamer 🇺🇸 693 83 357ms 5 Oct 2024 429th xyangst 692 93 10ms 1 Oct 2024 429th Salutations45 692 93 10ms 17 Nov 2024 429th strattonwhisler 692 93 9ms 26 Mar 2025 432nd NickTheEASDude 🇺🇸 690 115 3ms 17 Dec 2024 433rd pardouin 🇫🇷 688 57 4ms 3 Oct 2024 434th DialFrost 🇸🇬 687 94 15ms 1 Oct 2024 435th dokutan 687 116 7ms 19 Oct 2024 436th MeWhenI 🇻🇦 686 68 300ms 2 Oct 2024 437th Alex-x90 🇺🇸 686 100 2ms 1 Oct 2024 438th XenThe 🇬🇧 685 94 9ms 7 Jul 2025 439th error256 685 104 425ms 14 Oct 2024 440th ovs-code 🇩🇪 684 84 372ms 3 Oct 2024 441st KatieLG 🇬🇧 682 70 37ms 2 Oct 2025 442nd aDwarfNamedUrist 682 162 138ms 1 Sep 2025 443rd MeWhenI 🇻🇦 681 108 163ms 2 Oct 2024 444th Shanethegamer 🇺🇸 679 65 2ms 1 Oct 2024 445th emgordon154 679 101 2ms 25 Nov 2024 446th the-zammers 678 163 149ms 1 Dec 2024 447th Shanethegamer 🇺🇸 677 172 39ms 2 Oct 2024 448th plcc0 676 37 87ms 6 Apr 2025 449th snoozingnewt 🇨🇦 676 95 79ms 23 Oct 2025 450th MeWhenI 🇻🇦 673 96 16ms 30 Jul 2025 451st edsrzf 🇳🇿 673 99 4,316ms 5 Jul 2025 452nd tailorspy 673 128 423ms 4 Oct 2024 453rd jerrandolph 673 177 285ms 25 Sep 2025 453rd CaedenHarper 🇨🇦 673 177 278ms 17 Nov 2025 455th HumanoidCPU 670 96 9ms 7 Mar 2025 456th emgordon154 670 115 95ms 9 days ago 457th error256 669 101 4ms 24 Oct 2024 458th MeWhenI 🇻🇦 669 174 41ms 13 Feb 2025 459th madex 🇩🇪 666 103 1ms 2 Oct 2024 460th CaedenHarper 🇨🇦 666 140 692ms 3 Oct 2025 461st dbut2 🇦🇺 666 179 264ms 31 Oct 2024 462nd emgordon154 665 111 4ms 12 Jan 2025 463rd two-bad 🇬🇧 664 97 10ms 2 Oct 2024 463rd LordSir101 664 97 9ms 10 Aug 2025 465th AlephSquirrel 663 146 4ms 14 May 2025 466th snoozingnewt 🇨🇦 662 180 268ms 2 Nov 2025 467th 4hg 🇺🇸 661 59 34ms 5 Oct 2024 468th DialFrost 🇸🇬 659 67 2ms 22 Dec 2024 469th MeWhenI 🇻🇦 659 88 128ms 2 Oct 2024 469th Shanethegamer 🇺🇸 659 88 148ms 5 Oct 2024 471st GolfingSuccess 🇬🇷 659 98 16ms 5 Oct 2024 471st firegene 🇮🇪 659 98 18ms 21 Oct 2024 471st JunkIce 659 98 10ms 3 Dec 2024 474th BlankSpruce 659 104 2ms 1 Oct 2024 475th BambooleanLogic 🇸🇪 657 98 9ms 21 Oct 2024 476th error256 657 142 154ms 31 May 2025 477th jwhear 🇺🇸 655 197 1,696ms 1 Oct 2024 478th MeWhenI 🇻🇦 653 88 504ms 2 Oct 2024 479th Herbert00709 🇵🇱 653 105 2ms 14 Jun 2025 480th SirBogman 🇺🇸 652 99 16ms 8 Oct 2024 First Prev 401–480 of 846 Next Last