What makes a good word list for a fill-in puzzle?

A mix of word lengths works best — include words of 3, 4, 5, 6, 7, and 8+ letters. Words that share common letters (like E, A, T, S) intersect more often, creating a denser, more interesting puzzle.

How many words should I use for a word fill-in puzzle?

For the best results, use 8–20 words. Fewer than 8 words may produce a sparse grid, while more than 20 can make it harder for the algorithm to place every word.

Why are some words not placed in the fill-in grid?

The algorithm places words by finding valid intersections with existing words. If a word can't find a valid crossing point within the grid, it's omitted. Try adding more words with shared letters to improve placement rates.

How is a word fill-in puzzle different from a crossword?

In a crossword, clues tell you what the answer is. In a word fill-in (also called a Kriss-Kross), you're given the complete word list and must figure out which word fits each space based on letter count and intersecting letters.

Can I use fill-in puzzles for Amazon KDP publishing?

Yes. Fill-in puzzles are a popular KDP category. Our generator creates print-ready PDFs in KDP-compatible sizes (6×9 and 7×10 inches) with an answer key page included.

What is a word fill-in puzzle (also called Kriss-Kross)?

A word fill-in (Kriss-Kross) gives you a grid of empty boxes and a list of words to place. Unlike a crossword, there are no clues — instead, you figure out where each word fits based on letter count and where words must intersect. It's easier than a crossword but more challenging than a word search.

How is a fill-in puzzle different from a crossword for KDP?

Fill-in puzzles are faster to generate than crosswords (no clue writing required) and appeal to a different audience. They're a popular choice for KDP activity books because you can produce large volumes quickly using a generator.

Free Word Fill-In Maker — Printable Kriss-Kross PDF

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Want a head start? Print one of these free, ready-made word fill-in PDFs with an answer key, or open the maker above to build your own from any word list.