Aside from seeing a confused frown, another great way to see that a book isn’t readable for young children is if it doesn’t have the appropriate Spache grade. But what’s Spache, where did it come from and why is it so important?

What is a Spache score?

Spache is a readability test for English best for texts up to fourth-grade level. For grading texts aimed at older children for readability, the Dale-Chall test is more suitable.

As it is such a specialist tool meant for a specific age group, it is not really suitable for general readability use. For this reason, we don’t include it in our primary selection of algorithms we use to calculate our unique and reliable score.

However, our tool lists the Spache score for your text separately on a list of more specialist readability scores.

Whether you’re a teacher or a budding children’s author, you can use our tool to keep your young readers’ best interests.

Where did the test come from?

Spache was introduced by George Spache in 1952 in The Elementary School Journal. It’s a word-list style of formula which compares the words in a text to a set list of everyday words, which someone up to fourth grade generally can understand.

The formula was introduced by Spache in a journal article named ‘A New Readability Formula for Primary-Grade Reading Materials.’

He created the formula in response to many previous frameworks being formulated for the evaluation of material written for adults. Spache saw a neglected age group which needed to be accounted for.

He notes in the paper that there are other frameworks for analyzing below grade four, but that they’re too complicated to use.

Like us, he believed in innovating a way to make readability calculations quick and easy. Our tool, ReadablePro, makes it easier than ever to grade your text for readability.

How does the test work?

The variables in Spache’s formula are

  • Sentence length
  • Unfamiliar or difficult words

The formula is calculated as follows:

Spache readability formula


For your reference, here is the revised Spache word list. These are measured against the words used in the text in question. This allows for analysis of familiar versus unfamiliar words.

Originally, the formula collected data from a sample of 100-150 words.

For a longer text, this would have been tricky to calculate. Luckily, we can now automate the calculation. ReadablePro analyzes based on the entire text.

The calculation is a grade level based on the ASL - average sentence length - and PDW - percentage of difficult words.

After the original word list, Spache published a revised version - which we use today. The revised version was created in 1978. This is what he had to say about this decision:

“If a readability formula is to continue to reflect accurate estimates of the difficulty of today’s books it, too, must change.”

This shows his desire to keep up with the times and maintain his formula for contemporary use. Readability formulas like this aren’t static - they must evolve with time and changing conditions.

In a similar mindset, we are continually making improvements to ReadablePro and the more feedback we get from our users, the better.

If you have any ideas of features you’d like to see, please don’t hesitate to get in touch.

When is the Spache Readability Formula most useful?

We have previously discussed the importance of reading to children. The daily practice of this is extremely beneficial for parent-child bonding as well as helping children to develop early literacy skills.

It is useful, therefore, for parents to know that reading books with the appropriate rating will be comprehensible for their child. They will be able to fully understand the text until they’re ready for their next challenge.

But reading doesn’t of course stop at home. Spache is also invaluable for teachers.

This is because the Spache scoring on ReadablePro will quickly and easily tell you useful information such as the longest sentence in the text. It will also tell you how long the text would take to read.

As a case study, I uploaded a pdf copy to ReadablePro for analysis with the view of scoring it for a Spache grade. I wanted to confirm that The Lion Who Wouldn’t Try by Liza Esterhuyse is a suitable text for a child up to fourth grade.

Firstly, I uploaded the PDF copy to ReadablePro’s ‘score a file’ section. The file uploaded quickly and a few moments later I was emailed a link to view my file.

I then clicked ‘edit text’ to remove the eBook’s disclaimers. Once I had an accurate sample of the text, I looked at my results.

Being a children’s book, I was unsurprised to see that the overall readability rating was ‘A’.

The Spache score for The Lion Who Wouldn’t Try is 3.3.

This is great because it confirms for me that the book is below grade-four level. Which means it’s a great book for a small child’s library.

I was quickly able to retrieve other valuable information:

  • The speaking time is two minutes and ten seconds.
  • The text composition section lets me know via its statistics that the book is mostly comprised of nouns and verbs, so should not be complicated to understand.
  • The longest sentence is only eight words, so sentence length is also not too challenging for a very young reader.

With this being said, there is also a Word List Tools feature available. This allowed me to highlight all the words in the text which are not on the Spache list. This allows me to anticipate where there might be some problem words to overcome.

If you’re reading for or writing to young children, Spache will quickly and accurately tell you whether or not you’re speaking their language.

Laura Kelly

Laura is an English MA graduate who loves language, unputdownable books, coffee and being a Customer Success Champion at Readable. Her hobbies include sightseeing, sketching, and film photography.