The Calendar hole will go live in approximately 11 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 481st Herbert00709 🇵🇱 653 105 2ms 14 Jun 2025 482nd SirBogman 🇺🇸 652 99 16ms 8 Oct 2024 483rd voytxt 🇨🇿 651 89 129ms 17 Apr 2025 483rd dokutan 651 89 119ms 28 Jun 2025 485th w911 651 183 268ms 7 Oct 2024 486th albanian-laundromat 651 293 14ms 12 days ago 487th dokutan 650 99 8ms 28 Jun 2025 488th MeWhenI 🇻🇦 648 91 704ms 29 Aug 2025 489th rucin93 🇵🇱 648 144 143ms 28 Oct 2024 490th rniii 647 106 1ms 2 Oct 2024 490th gastropner 647 106 2ms 11 Feb 2025 492nd FlorianCassayre 🇫🇷 646 100 16ms 1 Oct 2024 492nd bzijlema 🇳🇱 646 100 16ms 10 Oct 2024 492nd bricknellj 646 100 16ms 4 Mar 2025 495th koipondx86 645 123 2ms 8 Nov 2024 496th CaedenHarper 🇨🇦 644 100 9ms 22 Aug 2025 496th iczelia 🇩🇪 644 100 9ms 11 Oct 2025 496th Yax42 🇫🇷 644 100 9ms 23 days ago 499th Shanethegamer 🇺🇸 643 124 6ms 4 Oct 2024 500th Apataras 643 145 381ms 25 Jun 2025 501st tomh1012 641 111 441ms 8 Sep 2025 502nd btjones0 640 101 16ms 2 Dec 2024 503rd stefangimmillaro 639 73 301ms 1 Oct 2024 504th elgan65536 639 146 147ms 2 Oct 2024 504th dokutan 639 146 382ms 26 days ago 504th luuumine 🇫🇷 639 146 146ms 23 days ago 507th MeWhenI 🇻🇦 638 73 8ms 3 Oct 2024 508th msbranicky 634 188 296ms 7 Jan 2025 509th annaproxy 633 102 16ms 1 Oct 2024 509th xyangst 633 102 10ms 1 Oct 2024 511th dokutan 632 91 345ms 19 Oct 2024 512th Shanethegamer 🇺🇸 631 74 278ms 16 Oct 2024 513th Florian-Mt 631 102 9ms 14 days ago 514th albanian-laundromat 631 264 492ms 3 Nov 2025 515th robin-scragg 627 103 11ms 21 Aug 2025 516th DialFrost 🇸🇬 627 304 153ms 13 Aug 2025 517th AlephSquirrel 625 40 40ms 1 Oct 2024 518th dokutan 624 127 2ms 10 Dec 2024 519th Jonatan6 🇩🇰 623 110 2ms 24 Oct 2024 519th solisolu 623 110 2ms 24 days ago 521st solisolu 621 104 9ms 15 Nov 2025 522nd codereport 🇨🇦 619 63 33ms 2 Oct 2024 523rd BalaM314 619 104 9ms 4 Feb 2025 523rd acollett89 619 104 9ms 15 Jul 2025 525th SirBogman 🇺🇸 618 93 384ms 23 Jul 2025 526th MarcMush 🇫🇷 617 91 893ms 8 Oct 2024 527th Ripick 617 135 346ms 23 Mar 2025 528th fourth-bit 615 105 19ms 1 Oct 2024 528th jared-hughes 615 105 15ms 3 Oct 2024 528th mattyhempstead 615 105 27ms 7 Oct 2024 531st olleicua 🇺🇸 612 78 40ms 18 Oct 2024 532nd evnu 612 147 78ms 12 Oct 2025 533rd bac0id 611 141 591ms 10 Jan 2025 534th davecame 609 106 15ms 1 Oct 2024 534th starfihs 609 106 10ms 2 Oct 2024 534th rschwa6308 🇺🇸 609 106 16ms 28 Oct 2024 534th snydej 609 106 15ms 21 Nov 2024 534th andrewjc2000 609 106 15ms 17 Jul 2025 534th travisdoesmath 609 106 16ms 7 Sep 2025 540th Seanharrs 609 117 470ms 15 Nov 2024 541st kaascevich 609 134 121ms 9 Jul 2025 542nd daveberlin 607 106 9ms 27 Jun 2025 543rd not-a-pokemon 607 113 2ms 23 Jul 2025 544th Shanethegamer 🇺🇸 606 154 145ms 3 Oct 2024 545th MeWhenI 🇻🇦 605 73 2ms 2 Oct 2024 546th alemelis 604 93 536ms 1 Oct 2024 547th commandblockguy 🇺🇸 604 107 15ms 7 Oct 2024 547th zbreit 🇺🇸 604 107 16ms 29 Oct 2024 547th StardustGogeta 604 107 16ms 30 Oct 2024 547th ZakkkkAttackkkk 🇵🇭 604 107 16ms 8 Feb 2025 547th InigoK 🇺🇸 604 107 16ms 22 Sep 2025 552nd jupj 🇫🇮 601 114 2ms 20 Jul 2025 553rd neihousaigaai 598 108 16ms 4 Oct 2024 553rd StefanHabel 🇨🇦 598 108 16ms 23 Jan 2025 553rd CaedenHarper 🇨🇦 598 108 16ms 22 Jul 2025 556th MeWhenI 🇻🇦 597 98 7ms 1 Oct 2024 557th dokutan 596 116 2ms 19 Nov 2025 558th arcpolaris 593 120 351ms 28 Jan 2025 559th SirBogman 🇺🇸 591 64 184ms 11 Jul 2025 560th JunkIce 587 98 346ms 3 Dec 2024 First Prev 481–560 of 848 Next Last