The Calendar hole will go live in approximately 12 days. Why not try and solve it ahead of time?
Card Number Validation in all languages in bytes. 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 Bytes Time Submitted 398th BrunoVisnadi 🇧🇷 738 108 16ms 1 Oct 2025 402nd lifthrasiir 🇰🇷 736 90 471ms 2 Dec 2024 403rd MeWhenI 🇻🇦 736 111 117ms 2 Oct 2024 404th MeWhenI 🇻🇦 735 34 64ms 2 Oct 2024 404th emgordon154 735 34 63ms 11 Sep 2025 406th stefangimmillaro 735 92 9ms 2 Oct 2024 406th Shanethegamer 🇺🇸 735 92 5ms 3 Oct 2024 408th Shanethegamer 🇺🇸 735 100 116ms 24 May 2025 409th Shanethegamer 🇺🇸 733 116 18ms 1 Oct 2024 410th kirjavascript 731 88 9ms 15 Mar 2025 411th Shanethegamer 🇺🇸 731 101 4ms 2 Oct 2024 412th stefangimmillaro 731 114 326ms 13 Oct 2024 413th MeWhenI 🇻🇦 730 174 41ms 13 Feb 2025 414th anter69 🇭🇺 729 78 1,023ms 1 Oct 2024 415th Shanethegamer 🇺🇸 729 112 106ms 3 Oct 2024 416th MeWhenI 🇻🇦 726 88 128ms 2 Oct 2024 416th Shanethegamer 🇺🇸 726 88 148ms 8 Jan 2025 418th cros107 🇦🇺 724 110 16ms 1 Jan 2025 418th guilhem-roy 🇫🇷 724 110 17ms 29 May 2025 418th Lv0Sys 🇵🇱 724 110 17ms 9 days ago 421st Shanethegamer 🇺🇸 724 126 1,275ms 2 Oct 2024 422nd dtbao20 🇻🇳 723 89 10ms 1 Oct 2024 422nd madeforlosers 723 89 8ms 17 Oct 2024 422nd junkondo-jp 723 89 9ms 14 Dec 2024 425th annaproxy 723 132 14ms 1 Oct 2024 426th MeWhenI 🇻🇦 721 179 1,697ms 7 Nov 2025 427th weeble 720 74 6ms 1 Jul 2025 428th MeWhenI 🇻🇦 720 78 416ms 2 Oct 2024 429th Shanethegamer 🇺🇸 720 96 2ms 3 Oct 2024 430th voytxt 🇨🇿 718 89 129ms 17 Apr 2025 431st mousetail 🇳🇱 718 111 16ms 6 Oct 2024 432nd alexsave 715 90 9ms 28 Oct 2024 433rd anter69 🇭🇺 713 67 47ms 1 Oct 2024 434th SirBogman 🇺🇸 713 93 384ms 23 Jul 2025 434th snoozingnewt 🇨🇦 713 93 407ms 13 days ago 436th snyderek 🇺🇸 712 121 53ms 1 Oct 2024 437th h3ra993huskp 🇯🇵 712 131 497ms 19 days ago 438th rzv-me 711 95 5ms 5 Oct 2024 439th OllieBoyne 🇬🇧 711 112 16ms 17 Oct 2024 439th WillConker 711 112 10ms 22 Oct 2024 439th maxgodfrey2004 🇨🇦 711 112 10ms 4 Jan 2025 439th Babafaba 711 112 16ms 11 Nov 2025 443rd Natanaelel 🇸🇪 709 55 34ms 1 Mar 2025 444th snoozingnewt 🇨🇦 709 95 79ms 23 Oct 2025 445th DialFrost 🇸🇬 709 106 11ms 13 Dec 2024 446th DialFrost 🇸🇬 707 132 225ms 8 Apr 2025 447th Shanethegamer 🇺🇸 706 118 357ms 2 Oct 2024 448th cbrt-x 706 157 139ms 1 Oct 2024 449th SB-945 705 113 16ms 1 Oct 2024 449th Artemis21 🇬🇧 705 113 16ms 23 Jan 2025 449th fkantelberg 705 113 10ms 11 Jul 2025 452nd MeWhenI 🇻🇦 704 115 435ms 5 Oct 2024 453rd Alex-x90 🇺🇸 703 100 2ms 1 Oct 2024 454th janlelis 702 68 60ms 1 Oct 2024 455th emgordon154 702 76 5ms 7 Jun 2025 456th BlankSpruce 701 123 480ms 1 Oct 2024 457th mousetail 🇳🇱 701 133 149ms 3 Oct 2024 458th LukeBridges 🇬🇧 700 92 9ms 3 Oct 2024 459th HumanoidCPU 699 114 62ms 7 Mar 2025 460th tobeannouncd 697 159 146ms 13 Dec 2024 461st emgordon154 696 101 2ms 25 Nov 2024 462nd emgordon154 696 134 224ms 25 Feb 2025 463rd Alex-x90 🇺🇸 695 124 498ms 1 Oct 2024 463rd Herbert00709 🇵🇱 695 124 56ms 14 Jun 2025 465th Shanethegamer 🇺🇸 693 41 3ms 4 Oct 2024 466th jipsong 🇩🇪 693 115 17ms 12 May 2025 466th luuumine 🇫🇷 693 115 20ms 17 days ago 468th Salutations45 692 93 10ms 17 Nov 2024 468th strattonwhisler 692 93 9ms 26 Mar 2025 470th NickTheEASDude 🇺🇸 690 115 3ms 17 Dec 2024 471st pardouin 🇫🇷 688 57 4ms 3 Oct 2024 472nd Bmrl7 687 116 10ms 3 Oct 2024 472nd rowechenzhong 687 116 9ms 17 Oct 2024 474th MeWhenI 🇻🇦 686 68 300ms 2 Oct 2024 475th error256 685 104 425ms 14 Oct 2024 476th aDwarfNamedUrist 684 162 138ms 1 Sep 2025 477th madex 🇩🇪 683 103 1ms 2 Oct 2024 478th MeWhenI 🇻🇦 681 108 163ms 2 Oct 2024 479th dtbao20 🇻🇳 681 117 16ms 1 Oct 2024 479th Pyroan 681 117 16ms 22 Feb 2025 First Prev 401–480 of 851 Next Last