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 160th nwellnhof 🇩🇪 853 46 4ms 7 Oct 2024 162nd sean-niemann 🇺🇸 853 56 37ms 8 Aug 2025 163rd JayXon 🇺🇸 853 95 424ms 4 Oct 2024 164th MostParsingVex 850 100 16ms 1 Oct 2024 165th error256 849 106 75ms 8 Oct 2024 166th emgordon154 848 67 1,010ms 18 Nov 2024 167th DialFrost 🇸🇬 848 94 15ms 1 Oct 2024 167th ndren 848 94 16ms 14 Feb 2025 169th edsrzf 🇳🇿 847 150 45ms 27 Feb 2025 170th primo-ppcg 🇹🇭 846 128 41ms 27 Apr 2025 171st lynn 846 131 138ms 8 Jan 2025 172nd KasperKivimaeki 🇫🇮 845 141 266ms 9 Oct 2025 173rd error256 844 94 2ms 7 Oct 2024 174th IanUtley 844 113 18ms 2 Oct 2024 175th CLOStrophobic 🇮🇹 844 119 6ms 24 Feb 2025 176th m-tkach 🇺🇦 842 144 79ms 8 Oct 2024 177th edsrzf 🇳🇿 840 111 395ms 3 hours ago 178th sean-niemann 🇺🇸 840 121 3ms 30 Nov 2024 179th moustave 839 95 19ms 4 Nov 2024 179th emgordon154 839 95 16ms 18 Nov 2024 181st emplv 🇱🇻 839 142 264ms 2 Oct 2024 181st sean-niemann 🇺🇸 839 142 264ms 2 Oct 2024 183rd xsot 🇸🇬 838 57 37ms 6 May 2025 184th nwellnhof 🇩🇪 837 84 2ms 2 Oct 2024 184th ovs-code 🇩🇪 837 84 1ms 2 Nov 2024 184th inventshah 837 84 2ms 31 Mar 2025 187th snoozingnewt 🇨🇦 837 92 96ms 32 hours ago 188th KasperKivimaeki 🇫🇮 837 103 428ms 11 days ago 189th JayXon 🇺🇸 837 109 1,287ms 5 Oct 2024 190th stefangimmillaro 836 68 1,045ms 2 Oct 2024 191st Shanethegamer 🇺🇸 836 77 9ms 1 Oct 2024 191st edsrzf 🇳🇿 836 77 9ms 10 May 2025 191st biocommando 🇫🇮 836 77 9ms 13 Jun 2025 194th m-tkach 🇺🇦 836 138 27ms 3 Oct 2024 195th emplv 🇱🇻 836 145 25ms 24 Oct 2024 196th GrayJoKing 🇦🇺 835 47 4ms 1 Oct 2024 197th sean-niemann 🇺🇸 835 114 42ms 2 Oct 2024 198th edsrzf 🇳🇿 835 115 4ms 3 hours ago 199th sean-niemann 🇺🇸 834 81 10ms 20 Dec 2024 200th edsrzf 🇳🇿 833 108 77ms 26 Jul 2025 201st stefangimmillaro 833 112 145ms 4 Oct 2024 202nd MeWhenI 🇻🇦 833 130 40ms 3 Oct 2024 203rd edsrzf 🇳🇿 833 133 182ms 22 hours ago 204th MeWhenI 🇻🇦 833 143 263ms 2 Oct 2024 205th ovs-code 🇩🇪 833 200 447ms 19 Apr 2025 206th stefangimmillaro 832 80 4,333ms 12 Nov 2024 207th JayXon 🇺🇸 832 155 2,650ms 3 Oct 2024 208th emplv 🇱🇻 830 77 128ms 28 Mar 2025 209th MeWhenI 🇻🇦 830 96 16ms 30 Jul 2025 210th edsrzf 🇳🇿 830 139 27ms 4 hours ago 211th saito-ta 🇯🇵 827 85 1ms 1 Oct 2024 212th dcgjb 825 78 9ms 6 May 2025 213th stefangimmillaro 825 99 109ms 3 Oct 2024 214th retrohun 824 71 9ms 10 Jan 2025 215th m-tkach 🇺🇦 823 58 55ms 8 Oct 2024 216th kg583 🇺🇸 823 115 8ms 17 Oct 2025 217th DialFrost 🇸🇬 822 82 103ms 23 Jun 2025 218th primo-ppcg 🇹🇭 822 232 525ms 13 Aug 2025 219th ovs-code 🇩🇪 820 65 5ms 30 Oct 2024 220th sean-niemann 🇺🇸 818 48 4ms 9 Aug 2025 221st MeWhenI 🇻🇦 818 114 494ms 7 Nov 2025 222nd MeWhenI 🇻🇦 817 92 10ms 24 Dec 2024 223rd MeWhenI 🇻🇦 817 104 18ms 2 Oct 2024 224th canissimia 🇦🇶 817 130 3ms 4 Oct 2024 225th MeWhenI 🇻🇦 817 186 14ms 2 Oct 2024 226th lifthrasiir 🇰🇷 815 197 10ms 19 Dec 2024 227th Shanethegamer 🇺🇸 814 69 346ms 2 Oct 2024 228th sisyphus-ppcg 🇦🇺 814 83 9ms 2 Oct 2024 229th MeWhenI 🇻🇦 814 85 2ms 5 Oct 2024 230th MeWhenI 🇻🇦 813 85 101ms 4 Oct 2024 231st GolfingSuccess 🇬🇷 813 98 16ms 5 Oct 2024 231st firegene 🇮🇪 813 98 18ms 21 Oct 2024 231st albanian-laundromat 813 98 16ms 3 Nov 2025 234th ovs-code 🇩🇪 813 106 428ms 1 Oct 2024 234th inventshah 813 106 516ms 1 Oct 2024 236th albanian-laundromat 813 118 4ms 8 days ago 237th emgordon154 813 205 464ms 7 Mar 2025 238th Shanethegamer 🇺🇸 812 70 986ms 9 Apr 2025 239th sean-niemann 🇺🇸 811 115 480ms 24 Sep 2025 239th stefangimmillaro 811 115 463ms 6 Oct 2025 First Prev 161–240 of 851 Next Last