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 398th GrayJoKing 🇦🇺 710 91 18ms 2 Jul 2025 402nd Natanaelel 🇸🇪 709 55 34ms 1 Mar 2025 403rd DialFrost 🇸🇬 709 106 11ms 13 Dec 2024 404th GrayJoKing 🇦🇺 707 82 127ms 1 Oct 2024 405th DialFrost 🇸🇬 707 132 225ms 8 Apr 2025 406th Shanethegamer 🇺🇸 706 118 357ms 2 Oct 2024 407th cbrt-x 706 157 139ms 1 Oct 2024 408th MeWhenI 🇻🇦 704 115 435ms 5 Oct 2024 409th janlelis 702 68 60ms 1 Oct 2024 409th tatzyr 🇯🇵 702 68 45ms 23 Dec 2024 411th emgordon154 702 76 5ms 7 Jun 2025 412th Shanethegamer 🇺🇸 702 92 16ms 3 Oct 2024 412th error256 702 92 20ms 7 Oct 2024 412th thatbirdguythatuknownot 702 92 16ms 14 Oct 2024 415th sean-niemann 🇺🇸 701 82 373ms 23 Dec 2024 416th BlankSpruce 701 123 480ms 1 Oct 2024 417th mousetail 🇳🇱 701 133 149ms 3 Oct 2024 418th LukeBridges 🇬🇧 700 92 9ms 3 Oct 2024 419th tobeannouncd 697 159 146ms 13 Dec 2024 420th emgordon154 696 134 224ms 25 Feb 2025 421st Bulmenisaurus 695 93 15ms 6 Oct 2024 421st lynn 695 93 16ms 8 Jan 2025 421st RaBa21 🇭🇺 695 93 17ms 19 Jul 2025 421st KasperKivimaeki 🇫🇮 695 93 17ms 18 days ago 421st blaztoma 🇱🇹 695 93 16ms 17 hours ago 426th Alex-x90 🇺🇸 695 124 498ms 1 Oct 2024 426th Herbert00709 🇵🇱 695 124 56ms 14 Jun 2025 428th Shanethegamer 🇺🇸 693 41 3ms 4 Oct 2024 429th Shanethegamer 🇺🇸 693 83 357ms 5 Oct 2024 430th xyangst 692 93 10ms 1 Oct 2024 430th Salutations45 692 93 10ms 17 Nov 2024 430th strattonwhisler 692 93 9ms 26 Mar 2025 433rd NickTheEASDude 🇺🇸 690 115 3ms 17 Dec 2024 434th pardouin 🇫🇷 688 57 4ms 3 Oct 2024 435th DialFrost 🇸🇬 687 94 15ms 1 Oct 2024 436th dokutan 687 116 7ms 19 Oct 2024 437th MeWhenI 🇻🇦 686 68 300ms 2 Oct 2024 438th Alex-x90 🇺🇸 686 100 2ms 1 Oct 2024 439th XenThe 🇬🇧 685 94 9ms 7 Jul 2025 440th error256 685 104 425ms 14 Oct 2024 441st ovs-code 🇩🇪 684 84 372ms 3 Oct 2024 442nd aDwarfNamedUrist 684 162 138ms 1 Sep 2025 443rd KatieLG 🇬🇧 682 70 37ms 2 Oct 2025 444th MeWhenI 🇻🇦 681 108 163ms 2 Oct 2024 445th the-zammers 680 163 149ms 1 Dec 2024 446th Shanethegamer 🇺🇸 679 65 2ms 1 Oct 2024 447th emgordon154 679 101 2ms 25 Nov 2024 448th Shanethegamer 🇺🇸 677 172 39ms 2 Oct 2024 449th plcc0 676 37 87ms 6 Apr 2025 450th snoozingnewt 🇨🇦 676 95 79ms 23 Oct 2025 451st MeWhenI 🇻🇦 673 96 16ms 30 Jul 2025 452nd edsrzf 🇳🇿 673 99 4,316ms 5 Jul 2025 453rd tailorspy 673 128 423ms 4 Oct 2024 454th jerrandolph 673 177 285ms 25 Sep 2025 454th CaedenHarper 🇨🇦 673 177 278ms 17 Nov 2025 456th HumanoidCPU 670 96 9ms 7 Mar 2025 457th emgordon154 670 115 95ms 9 days ago 458th error256 669 101 4ms 24 Oct 2024 459th MeWhenI 🇻🇦 669 174 41ms 13 Feb 2025 460th madex 🇩🇪 666 103 1ms 2 Oct 2024 461st CaedenHarper 🇨🇦 666 140 692ms 3 Oct 2025 462nd dbut2 🇦🇺 666 179 264ms 31 Oct 2024 463rd emgordon154 665 111 4ms 12 Jan 2025 464th two-bad 🇬🇧 664 97 10ms 2 Oct 2024 464th LordSir101 664 97 9ms 10 Aug 2025 466th AlephSquirrel 663 146 4ms 14 May 2025 467th snoozingnewt 🇨🇦 662 180 268ms 2 Nov 2025 468th 4hg 🇺🇸 661 59 34ms 5 Oct 2024 469th DialFrost 🇸🇬 659 67 2ms 22 Dec 2024 470th MeWhenI 🇻🇦 659 88 128ms 2 Oct 2024 470th Shanethegamer 🇺🇸 659 88 148ms 5 Oct 2024 472nd GolfingSuccess 🇬🇷 659 98 16ms 5 Oct 2024 472nd firegene 🇮🇪 659 98 18ms 21 Oct 2024 472nd JunkIce 659 98 10ms 3 Dec 2024 475th BlankSpruce 659 104 2ms 1 Oct 2024 476th BambooleanLogic 🇸🇪 657 98 9ms 21 Oct 2024 477th error256 657 142 154ms 31 May 2025 478th jwhear 🇺🇸 655 197 1,696ms 1 Oct 2024 479th MeWhenI 🇻🇦 653 88 504ms 2 Oct 2024 480th Herbert00709 🇵🇱 653 105 2ms 14 Jun 2025 First Prev 401–480 of 847 Next Last