Book Sort is a free online ordering puzzle that runs in the browser with no download and no account. A shelf of books comes back jumbled and you put it right one book at a time: take a book out, slide it back in anywhere. Some levels sort by the number on the spine, some alphabetically, and some by height alone with the spines left blank so size is the only clue you get. What makes it a puzzle rather than a chore is the par. The fewest moves any shelf needs is exactly the number of books minus the longest run already in the right order relative to each other — a figure the game works out for your shelf and prints in the header, so you always know what a perfect solve looks like. Spotting that run before you start moving things is the whole skill.
How to play Book Sort
- The line under the header says what this shelf is sorted by — spine numbers, height, or alphabetically by the letter on the spine.
- Tap a book to lift it off the shelf. It stays visible, raised, so you can see what you are holding.
- Gaps appear between the remaining books. Tap one to slide the book back in there. That counts as one move.
- Putting a book back exactly where it came from is free, so you can pick things up to look without being charged for it.
- On height levels the spines are blank. Judging the order by eye is the level.
- The header shows your moves against par. Par is the exact minimum for your shelf, not an estimate.
- Hint lifts the next book of a perfect solution and highlights the gap it should go in. It works from whatever state the shelf is in, so it never walks you into a corner.
- Undo steps back one insertion and costs a move, so par cannot be reached by trial and error. Matching par is three stars, within three of it is two.
Tips
- Find the run before you move anything. Look for the longest set of books that are already in the right order relative to each other — those never need to move, and everything else does.
- That run does not have to be next to each other. On a shelf reading 3, 1, 4, 2, 5 the books 3, 4, 5 are already in order, so only two books need reshelving.
- Move books in order of where they belong. Placing them smallest-first means every book you insert has a settled neighbour to measure against.
- On height levels, compare against the neighbours rather than the whole shelf. Getting each pair the right way round gets you most of the way there.
- Beware the tempting swap. Exchanging two books looks like one action but is two insertions, and it is the most common way to finish three over par.
- If a shelf is nearly sorted, count what is out of place before touching anything. One badly chosen first move can turn a two-move shelf into a five-move one.
- Undo costs a move, so use Hint instead when you are stuck. It is not free either — it shows in the result card — but it does not push you further from par.
FAQ
Is Book Sort free to play?
Yes. It runs in your browser with no download, no sign-up and nothing to buy. All twelve levels are included and unlock in order.
How is par calculated?
Exactly, not by estimate. The fewest insertions needed to sort a row is the number of books minus the length of the longest already-in-order subsequence, because every other book must move at least once and moving exactly those is enough. The game computes that for your shelf and shows it.
How is this different from the other sorting games here?
Ball Sort, Water Sort and Coin Sort all put things into containers. There are no containers here — the shelf is one row and the question is only whether it is in order. That makes it a sequencing puzzle, closer to a sliding puzzle than to a sorting-into-bins one.
What does a move actually do?
It takes one book out and puts it back at any position, with the rest closing up and making room. That single operation is enough to sort any shelf; the puzzle is doing it as few times as possible.
Why are some spines blank?
Those are the sort-by-height levels. Printing a number on the spine there would answer the question the level is asking, so the books carry nothing but their size.
Is there a timer or a move limit?
Neither. Par only affects the star rating, and you can take as many moves as you like. There is no way to fail a shelf.
Does the hint ever give bad advice?
No. It recalculates a perfect solution from the shelf in front of you every time, so even if you have moved things in a way it would not have chosen, its next suggestion is still optimal from where you are.
Does Book Sort work on a phone?
Yes. Spines shrink to fit the screen width and the gaps stay wide enough to tap, so a twelve-book shelf works in portrait.