The FLOSS Rule

You must have seen words with a double consonant at the end, like less, and others aren’t (like cob)? There is actually a reason for this , and it’s called The Floss Rule. The Floss Rule helps you know when to double the final consonant and it’s a pretty easy rule to learn.

Check out this handy rule in the video below, and then read on for free printable spelling rule posters!


In this blog post, we’ll discuss what is the floss rule , how to teach it, and some fun activities that you can do with your students. So let’s get started!

What is the floss rule?
The floss rule for spelling is the rule that states that l, f, s, and z are almost always doubled when they come at the end of a one-syllable word and are preceded by a short vowel.

Examples of floss rule words include`: mass, cliff, bill, and jazz.

There are a few exceptions to this rule and I would teach them as heart words: bus, us, plus, of, if, yes, this, gal and quiz.

Floss Rule Anchor Chart
You can print out this floss rule anchor chart to display in your classroom/home and help your students/kids remember this rule. Just click on the poster and save the pdf to your device.

Floss Rule Words and worksheet
I also created this printable list of floss words that you can use for your lessons and activities. Just click on the poster and save the pdf to your device

This post may include affiliate links which means I may earn a commission on qualifying purchases at no additional cost to you.

When to teach the floss rule
Teach the floss rule after students have learned all the consonants and short vowels.If your child is still learning phonics then try our free phonics worksheets. I usually teach it after CVC words and before consonant blends. This is usually in kindergarten.

Floss Rule Activities
There are many activities you can find to work on the Floss Rule, mostly worksheets and games.
Highlight the doubled spelling in the words on the page.
After this I have students write some floss words, making sure they say the letter aloud as they write.
Give list of words to sort. Sorting helps students see the patterns. You can sort non-floss words with floss words, or sort floss words by their ending.

Spelling rules are very helpful to read and write English spellings. Here are other  SPELLING RULES that may help you.

Do not forget to talk about the exceptions. When you introduce this rule make sure to state that it ‘almost always’ is the case and not always, since there are some exceptions. And Many times there is a good reason why a word doesn’t follow the rule. For example, the word chef is a French word so it won’t follow English conventions.

The floss rule is a great spelling strategy to teach young students. It’s easy to learn and helps them spell common words correctly. Using the methods and activities in this post you can help your students learn the floss rule.

Has the Floss Rule helped your child? I would love to hear about it . Do tag us on facebook or instagram! And check out our other spelling rules, too!
Learn about other spelling rules from here.


These short a Floss rule poster and worksheet are available for personal and single classroom use. You are not licensed to redistribute the files to other parents/teachers for use with their children/students. Instead, please refer them to this page so they can download their own copy.

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