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 481st SirBogman 🇺🇸 652 99 16ms 8 Oct 2024 482nd voytxt 🇨🇿 651 89 129ms 17 Apr 2025 482nd dokutan 651 89 119ms 28 Jun 2025 484th w911 651 183 268ms 7 Oct 2024 485th albanian-laundromat 651 293 14ms 10 days ago 486th dokutan 650 99 8ms 28 Jun 2025 487th MeWhenI 🇻🇦 648 91 704ms 29 Aug 2025 488th rucin93 🇵🇱 648 144 143ms 28 Oct 2024 489th rniii 647 106 1ms 2 Oct 2024 489th gastropner 647 106 2ms 11 Feb 2025 491st FlorianCassayre 🇫🇷 646 100 16ms 1 Oct 2024 491st bzijlema 🇳🇱 646 100 16ms 10 Oct 2024 491st bricknellj 646 100 16ms 4 Mar 2025 494th koipondx86 645 123 2ms 8 Nov 2024 495th CaedenHarper 🇨🇦 644 100 9ms 22 Aug 2025 495th iczelia 🇩🇪 644 100 9ms 11 Oct 2025 495th Yax42 🇫🇷 644 100 9ms 21 days ago 498th Shanethegamer 🇺🇸 643 124 6ms 4 Oct 2024 499th Apataras 643 145 381ms 25 Jun 2025 500th tomh1012 641 111 441ms 8 Sep 2025 501st btjones0 640 101 16ms 2 Dec 2024 502nd stefangimmillaro 639 73 301ms 1 Oct 2024 503rd elgan65536 639 146 147ms 2 Oct 2024 503rd dokutan 639 146 382ms 24 days ago 503rd luuumine 🇫🇷 639 146 146ms 22 days ago 506th MeWhenI 🇻🇦 638 73 8ms 3 Oct 2024 507th msbranicky 634 188 296ms 7 Jan 2025 508th annaproxy 633 102 16ms 1 Oct 2024 508th xyangst 633 102 10ms 1 Oct 2024 510th dokutan 632 91 345ms 19 Oct 2024 511th Shanethegamer 🇺🇸 631 74 278ms 16 Oct 2024 512th Florian-Mt 631 102 9ms 13 days ago 513th albanian-laundromat 631 264 492ms 3 Nov 2025 514th robin-scragg 627 103 11ms 21 Aug 2025 515th DialFrost 🇸🇬 627 304 153ms 13 Aug 2025 516th AlephSquirrel 625 40 40ms 1 Oct 2024 517th dokutan 624 127 2ms 10 Dec 2024 518th Jonatan6 🇩🇰 623 110 2ms 24 Oct 2024 518th solisolu 623 110 2ms 23 days ago 520th solisolu 621 104 9ms 15 Nov 2025 521st codereport 🇨🇦 619 63 33ms 2 Oct 2024 522nd BalaM314 619 104 9ms 4 Feb 2025 522nd acollett89 619 104 9ms 15 Jul 2025 524th SirBogman 🇺🇸 618 93 384ms 23 Jul 2025 525th MarcMush 🇫🇷 617 91 893ms 8 Oct 2024 526th Ripick 617 135 346ms 23 Mar 2025 527th fourth-bit 615 105 19ms 1 Oct 2024 527th jared-hughes 615 105 15ms 3 Oct 2024 527th mattyhempstead 615 105 27ms 7 Oct 2024 530th olleicua 🇺🇸 612 78 40ms 18 Oct 2024 531st evnu 612 147 78ms 12 Oct 2025 532nd bac0id 611 141 591ms 10 Jan 2025 533rd davecame 609 106 15ms 1 Oct 2024 533rd starfihs 609 106 10ms 2 Oct 2024 533rd rschwa6308 🇺🇸 609 106 16ms 28 Oct 2024 533rd snydej 609 106 15ms 21 Nov 2024 533rd andrewjc2000 609 106 15ms 17 Jul 2025 533rd travisdoesmath 609 106 16ms 7 Sep 2025 539th Seanharrs 609 117 470ms 15 Nov 2024 540th kaascevich 609 134 121ms 9 Jul 2025 541st daveberlin 607 106 9ms 27 Jun 2025 542nd not-a-pokemon 607 113 2ms 23 Jul 2025 543rd Shanethegamer 🇺🇸 606 154 145ms 3 Oct 2024 544th MeWhenI 🇻🇦 605 73 2ms 2 Oct 2024 545th alemelis 604 93 536ms 1 Oct 2024 546th commandblockguy 🇺🇸 604 107 15ms 7 Oct 2024 546th zbreit 🇺🇸 604 107 16ms 29 Oct 2024 546th StardustGogeta 604 107 16ms 30 Oct 2024 546th ZakkkkAttackkkk 🇵🇭 604 107 16ms 8 Feb 2025 546th InigoK 🇺🇸 604 107 16ms 22 Sep 2025 551st jupj 🇫🇮 601 114 2ms 20 Jul 2025 552nd neihousaigaai 598 108 16ms 4 Oct 2024 552nd StefanHabel 🇨🇦 598 108 16ms 23 Jan 2025 552nd CaedenHarper 🇨🇦 598 108 16ms 22 Jul 2025 555th MeWhenI 🇻🇦 597 98 7ms 1 Oct 2024 556th dokutan 596 116 2ms 19 Nov 2025 557th arcpolaris 593 120 351ms 28 Jan 2025 558th SirBogman 🇺🇸 591 64 184ms 11 Jul 2025 559th JunkIce 587 98 346ms 3 Dec 2024 559th commandblockguy 🇺🇸 587 98 471ms 1 Sep 2025 First Prev 481–560 of 847 Next Last