Captain Underpants Reading Level: Every Book, Lexile and ATOS

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Straight answer first, because this one surprises people.

The twelve Captain Underpants books run ATOS 4.3 to 5.3 and Lexile 640L to 890L. Renaissance files all twelve at interest level grades 4 to 8.

Now hold that next to Dog Man. Same author. ATOS 2.3 to 3.2. Interest level K to 3.

Captain Underpants is about two grade levels harder.

Same author. Same humor. Same kid energy. Completely different reading demand.

If you've been handing both to the same child, that's the thing worth knowing.

I'm Jimmy Vee. I write funny picture books and I've performed for kids for thirty years. Everything here comes from Renaissance Accelerated Reader BookFinder, the same database your school's AR program uses.

Captain Underpants reading levels, all 12 books

# Title Year Lexile ATOS Words Pages
1 The Adventures of Captain Underpants 1997 720L 4.3 5,731 120
2 ...and the Attack of the Talking Toilets 1999 780L 4.7 5,595 139
3 ...and the Invasion of the Incredibly Naughty Cafeteria Ladies from Outer Space 1999 730L 4.4 4,668 141
4 ...and the Perilous Plot of Professor Poopypants 2000 720L 4.7 5,582 153
5 ...and the Wrath of the Wicked Wedgie Woman 2001 640L 4.4 7,389 165
6 ...and the Big, Bad Battle of the Bionic Booger Boy, Part 1 2003 850L 5.2 7,560 173
7 ...and the Big, Bad Battle of the Bionic Booger Boy, Part 2 2003 710L 4.9 8,531 173
8 ...and the Preposterous Plight of the Purple Potty People 2006 760L 4.7 7,177 175
9 ...and the Terrifying Return of Tippy Tinkletrousers 2012 850L 5.1 17,957 302
10 ...and the Revolting Revenge of the Radioactive Robo-Boxers 2013 890L 5.3 12,515 219
11 ...and the Tyrannical Retaliation of the Turbo Toilet 2000 2014 770L 4.8 12,145 222
12 ...and the Sensational Saga of Sir Stinks-A-Lot 2015 800L 4.9 10,186 205

All twelve by Dav Pilkey. The series ended at book 12 in 2015, and Pilkey moved on to Dog Man.

Why it measures so much higher than Dog Man

Look at the Lexile column again. No GN prefix anywhere.

Dog Man is a graphic novel. Its Lexile carries a GN code, which tells you the measure only read the text and the text is only half the book.

Captain Underpants is not a graphic novel.

It's a chapter book with comics inside it. Real paragraphs. Full sentences. Narration doing actual work between the Flip-O-Rama pages.

So the measure reads a lot more prose, and the number climbs.

That's the whole explanation. But it catches parents out constantly. The two series look like cousins on a shelf. In reading terms they're years apart.

The series gets much bigger, and it does climb

Unlike Dog Man and Magic Tree House, this one actually does get harder.

Book 1 is ATOS 4.3. Book 10 is 5.3.

That's a full grade level of drift. More movement than any other series I've charted here.

And the size change is dramatic.

Book 3 is 4,668 words across 141 pages.

Book 9 is 17,957 words across 302 pages.

Nearly four times the text.

Book 9, Tippy Tinkletrousers, is the only one worth 3.0 AR points. It's the outlier of the set by a wide margin.

So the kid who started at book 1 finishes on a much bigger, harder book. That's fine. Just know it before you hand book 9 to a reader who loved book 1 two years ago.

The manga version is a different book

There's now Captain Underpants: The First Epic Manga. It is not the same reading experience.

Renaissance has it at 510L and ATOS 3.0. The original is 720L and 4.3.

So that's a real option if your reader loves the character but isn't ready for the prose.

It also means you should check which one is actually in your kid's hands before you conclude anything from a level.

What the numbers won't tell you

The reading level says nothing about the content, and with this series the content is the part parents ask about.

It is relentlessly, deliberately gross. Waistbands, toilets, boogers, invented swear words.

Two fourth graders hypnotize their principal. That's the premise, and it never apologizes for it.

Some grown-ups can't stand it. Some kids have read every one twice.

Here's what I'd say, having stood in front of a lot of elementary school gyms. The kids who love this series are very often the kids who weren't reading anything before it.

That counts for something.

It counted for enough that Pilkey built a second, easier series on the same two characters. A lot of readers came to Dog Man through George and Harold.

The level tells you whether they can. It won't tell you whether they'll want to.

With this series, wanting to was never the problem.

Related

Sources: Lexile measures, ATOS levels, word counts, AR points, interest levels and page counts are from Renaissance Accelerated Reader BookFinder, retrieved September 16, 2026.

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