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 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 401st MeWhenI 🇻🇦 736 111 117ms 2 Oct 2024 402nd MeWhenI 🇻🇦 735 34 64ms 2 Oct 2024 402nd emgordon154 735 34 63ms 11 Sep 2025 404th stefangimmillaro 735 92 9ms 2 Oct 2024 404th Shanethegamer 🇺🇸 735 92 5ms 3 Oct 2024 406th Shanethegamer 🇺🇸 735 100 116ms 24 May 2025 407th Shanethegamer 🇺🇸 733 116 18ms 1 Oct 2024 408th Shanethegamer 🇺🇸 732 156 30ms 2 Oct 2024 409th kirjavascript 731 88 9ms 15 Mar 2025 410th Shanethegamer 🇺🇸 731 101 4ms 2 Oct 2024 411th stefangimmillaro 731 114 326ms 13 Oct 2024 412th MeWhenI 🇻🇦 730 174 41ms 13 Feb 2025 413th anter69 🇭🇺 729 78 1,023ms 1 Oct 2024 414th Shanethegamer 🇺🇸 729 112 106ms 3 Oct 2024 415th MeWhenI 🇻🇦 726 88 128ms 2 Oct 2024 415th Shanethegamer 🇺🇸 726 88 148ms 8 Jan 2025 417th cros107 🇦🇺 724 110 16ms 1 Jan 2025 417th guilhem-roy 🇫🇷 724 110 17ms 29 May 2025 417th Lv0Sys 🇵🇱 724 110 17ms 8 days ago 420th Shanethegamer 🇺🇸 724 126 1,275ms 2 Oct 2024 421st dtbao20 🇻🇳 723 89 10ms 1 Oct 2024 421st madeforlosers 723 89 8ms 17 Oct 2024 421st junkondo-jp 723 89 9ms 14 Dec 2024 424th annaproxy 723 132 14ms 1 Oct 2024 425th MeWhenI 🇻🇦 721 179 1,697ms 7 Nov 2025 426th weeble 720 74 6ms 1 Jul 2025 427th MeWhenI 🇻🇦 720 78 416ms 2 Oct 2024 428th Shanethegamer 🇺🇸 720 96 2ms 3 Oct 2024 429th voytxt 🇨🇿 718 89 129ms 17 Apr 2025 430th mousetail 🇳🇱 718 111 16ms 6 Oct 2024 431st alexsave 715 90 9ms 28 Oct 2024 432nd anter69 🇭🇺 713 67 47ms 1 Oct 2024 433rd SirBogman 🇺🇸 713 93 384ms 23 Jul 2025 433rd snoozingnewt 🇨🇦 713 93 407ms 12 days ago 435th snyderek 🇺🇸 712 121 53ms 1 Oct 2024 436th h3ra993huskp 🇯🇵 712 131 497ms 18 days ago 437th rzv-me 711 95 5ms 5 Oct 2024 438th OllieBoyne 🇬🇧 711 112 16ms 17 Oct 2024 438th WillConker 711 112 10ms 22 Oct 2024 438th maxgodfrey2004 🇨🇦 711 112 10ms 4 Jan 2025 438th Babafaba 711 112 16ms 11 Nov 2025 442nd Natanaelel 🇸🇪 709 55 34ms 1 Mar 2025 443rd snoozingnewt 🇨🇦 709 95 79ms 23 Oct 2025 444th DialFrost 🇸🇬 709 106 11ms 13 Dec 2024 445th DialFrost 🇸🇬 707 132 225ms 8 Apr 2025 446th Shanethegamer 🇺🇸 706 118 357ms 2 Oct 2024 447th cbrt-x 706 157 139ms 1 Oct 2024 448th SB-945 705 113 16ms 1 Oct 2024 448th Artemis21 🇬🇧 705 113 16ms 23 Jan 2025 448th fkantelberg 705 113 10ms 11 Jul 2025 451st MeWhenI 🇻🇦 704 115 435ms 5 Oct 2024 452nd Alex-x90 🇺🇸 703 100 2ms 1 Oct 2024 453rd janlelis 702 68 60ms 1 Oct 2024 454th emgordon154 702 76 5ms 7 Jun 2025 455th BlankSpruce 701 123 480ms 1 Oct 2024 456th mousetail 🇳🇱 701 133 149ms 3 Oct 2024 457th LukeBridges 🇬🇧 700 92 9ms 3 Oct 2024 458th HumanoidCPU 699 114 62ms 7 Mar 2025 459th tobeannouncd 697 159 146ms 13 Dec 2024 460th emgordon154 696 101 2ms 25 Nov 2024 461st emgordon154 696 134 224ms 25 Feb 2025 462nd Alex-x90 🇺🇸 695 124 498ms 1 Oct 2024 462nd Herbert00709 🇵🇱 695 124 56ms 14 Jun 2025 464th Shanethegamer 🇺🇸 693 41 3ms 4 Oct 2024 465th jipsong 🇩🇪 693 115 17ms 12 May 2025 465th luuumine 🇫🇷 693 115 20ms 16 days ago 467th Salutations45 692 93 10ms 17 Nov 2024 467th strattonwhisler 692 93 9ms 26 Mar 2025 469th NickTheEASDude 🇺🇸 690 115 3ms 17 Dec 2024 470th pardouin 🇫🇷 688 57 4ms 3 Oct 2024 471st Bmrl7 687 116 10ms 3 Oct 2024 471st rowechenzhong 687 116 9ms 17 Oct 2024 473rd MeWhenI 🇻🇦 686 68 300ms 2 Oct 2024 474th error256 685 104 425ms 14 Oct 2024 475th aDwarfNamedUrist 684 162 138ms 1 Sep 2025 476th madex 🇩🇪 683 103 1ms 2 Oct 2024 477th MeWhenI 🇻🇦 681 108 163ms 2 Oct 2024 478th dtbao20 🇻🇳 681 117 16ms 1 Oct 2024 478th Pyroan 681 117 16ms 22 Feb 2025 478th vgamula 🇺🇦 681 117 19ms 5 Aug 2025 First Prev 401–480 of 850 Next Last