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 319th Larento 775 83 9ms 4 Nov 2024 319th Andrey-Plotnikov 775 83 9ms 13 Jan 2025 319th nathanadams 🇳🇿 775 83 9ms 6 Oct 2025 324th duckyluuk 🇳🇱 775 97 9ms 22 days ago 325th Natanaelel 🇸🇪 772 143 148ms 20 Apr 2025 326th sean-niemann 🇺🇸 771 105 440ms 1 Oct 2024 327th DialFrost 🇸🇬 771 121 349ms 24 Sep 2025 328th sisyphus-ppcg 🇦🇺 770 62 59ms 3 Oct 2024 329th emgordon154 770 83 127ms 18 Nov 2024 330th Waffle3z 770 103 1ms 2 Oct 2024 331st retrohun 769 63 25ms 2 Oct 2024 332nd edsrzf 🇳🇿 769 76 1,005ms 1 Oct 2024 333rd DialFrost 🇸🇬 769 90 2ms 18 Nov 2025 334th targrik 768 88 8ms 7 Feb 2025 335th lifthrasiir 🇰🇷 767 37 2ms 27 Nov 2024 336th didion0 🇺🇸 766 84 9ms 10 Jan 2025 337th jatloe 766 104 9ms 1 Oct 2024 337th solisolu 766 104 9ms 15 Nov 2025 339th DialFrost 🇸🇬 766 131 7ms 11 Dec 2024 340th MeWhenI 🇻🇦 765 109 334ms 2 Oct 2024 340th edsrzf 🇳🇿 765 109 365ms 23 Jul 2025 342nd luuumine 🇫🇷 764 92 1ms 12 days ago 342nd bzd7 764 92 2ms 11 days ago 344th ovs-code 🇩🇪 764 122 159ms 25 Apr 2025 345th albanian-laundromat 763 118 77ms 13 Nov 2025 346th Shanethegamer 🇺🇸 763 124 6ms 4 Oct 2024 347th GolfingSuccess 🇬🇷 762 70 6ms 6 Jun 2025 348th Shanethegamer 🇺🇸 761 132 7ms 2 Oct 2024 349th MeWhenI 🇻🇦 759 89 5ms 2 Oct 2024 350th fourth-bit 759 105 19ms 1 Oct 2024 350th jared-hughes 759 105 15ms 3 Oct 2024 350th mattyhempstead 759 105 27ms 7 Oct 2024 353rd emgordon154 758 63 40ms 18 Nov 2024 353rd SirBogman 🇺🇸 758 63 33ms 19 Jul 2025 355th weliveinhell 🇭🇹 757 85 9ms 1 Oct 2024 355th SteRoy 757 85 9ms 13 May 2025 357th sean-niemann 🇺🇸 756 93 3ms 24 Oct 2024 358th 0xjac 🇨🇭 754 158 256ms 17 Jun 2025 359th MeWhenI 🇻🇦 753 88 504ms 2 Oct 2024 359th albanian-laundromat 753 88 532ms 3 Nov 2025 361st davecame 752 106 15ms 1 Oct 2024 361st starfihs 752 106 10ms 2 Oct 2024 361st rschwa6308 🇺🇸 752 106 16ms 28 Oct 2024 361st snydej 752 106 15ms 21 Nov 2024 361st andrewjc2000 752 106 15ms 17 Jul 2025 361st qpwoeirut 752 106 9ms 19 Aug 2025 367th GrayJoKing 🇦🇺 751 90 4ms 1 Oct 2024 368th stackofbears 750 52 35ms 14 Mar 2025 369th MeWhenI 🇻🇦 749 162 26ms 2 Oct 2024 370th Maznek 748 86 10ms 4 Oct 2024 371st MeWhenI 🇻🇦 748 89 4,060ms 24 Oct 2024 372nd stefangimmillaro 748 94 1ms 30 Oct 2024 373rd MeWhenI 🇻🇦 748 106 1ms 2 Oct 2024 374th rak1507 🇬🇧 747 38 2ms 30 Dec 2024 375th Shanethegamer 🇺🇸 746 64 53ms 3 Oct 2024 375th Andriamanitra 🇫🇮 746 64 41ms 5 Oct 2024 377th commandblockguy 🇺🇸 745 107 15ms 7 Oct 2024 377th zbreit 🇺🇸 745 107 16ms 29 Oct 2024 377th StardustGogeta 745 107 16ms 30 Oct 2024 377th ZakkkkAttackkkk 🇵🇭 745 107 16ms 8 Feb 2025 377th InigoK 🇺🇸 745 107 16ms 22 Sep 2025 382nd Shanethegamer 🇺🇸 744 121 83ms 3 Oct 2024 383rd sean-niemann 🇺🇸 743 93 101ms 24 Oct 2024 384th sean-niemann 🇺🇸 743 116 469ms 24 Oct 2024 384th luuumine 🇫🇷 743 116 517ms 3 days ago 386th SirBogman 🇺🇸 741 63 278ms 23 Jul 2025 387th GrayJoKing 🇦🇺 740 79 1,204ms 1 Oct 2024 388th KrausRaus 🇺🇸 740 87 9ms 1 Oct 2024 388th GeorgeStechman 🇬🇧 740 87 9ms 24 Oct 2024 388th coreynash 740 87 9ms 13 Feb 2025 391st Shanethegamer 🇺🇸 740 90 3,803ms 28 Oct 2024 391st ScottHamper 740 90 2,700ms 7 days ago 393rd DialFrost 🇸🇬 739 76 1,019ms 9 Oct 2024 394th Shanethegamer 🇺🇸 739 172 39ms 2 Oct 2024 395th neihousaigaai 738 108 16ms 4 Oct 2024 395th StefanHabel 🇨🇦 738 108 16ms 23 Jan 2025 395th CaedenHarper 🇨🇦 738 108 16ms 22 Jul 2025 395th BrunoVisnadi 🇧🇷 738 108 16ms 1 Oct 2025 399th lifthrasiir 🇰🇷 736 90 471ms 2 Dec 2024 400th MeWhenI 🇻🇦 736 111 117ms 2 Oct 2024 First Prev 321–400 of 849 Next Last