Adding suffixes: the spelling rules
Four rules cover almost every change to a root word when a suffix is added: double the consonant, drop the e, change y to i, or just add it. Most Year 6 spelling errors in writing come from one of these.
Why suffixes matter so much
Most of the longer words children write are root words with a suffix: stopped, hoping, happiness, carefully, dramatically. The suffix itself is rarely the problem. The problem is what happens to the root word at the join. Teach the four rules below and a huge number of everyday spellings fall into place.
Rule 1: double the final consonant
When a short word ends in one vowel and one consonant, double the consonant before adding a suffix that starts with a vowel (-ing, -ed, -er, -est).
- stopped, running, biggerOne vowel, one consonant: double it.
- jumped, rainingTwo consonants or two vowels: just add.
For longer words, the consonant doubles only if the last syllable is stressed: beGIN, beginning; forGET, forgetting; preFER, preferred. If the stress is earlier, it doesn't double: GARden, gardening; LIMit, limited.
Rule 2: drop the e
When a word ends in a silent e, drop it before adding a suffix that starts with a vowel.
- hoping, making, adorableDrop the e.
- hopeful, lately, movementSuffix starts with a consonant: keep the e.
The exception is after a soft c or g, where the e stays to keep the sound soft: noticeable, courageous.
Rule 3: change y to i
When a word ends in a consonant followed by y, change the y to i before most suffixes.
- happiness, tried, babies, angrilyConsonant + y: change to i.
- played, enjoymentVowel + y: keep the y.
- cryingKeep the y before -ing, or you'd get ii.
The same rule explains plurals such as opportunities, histories and secretaries, which is why the y-ending lists are grouped here.
Rule 4: adverbs with -ly
Most adjectives just add -ly: quick, quickly; sincere, sincerely. Then three special cases:
- Words ending in -le drop the e and add -y: gentle, gently; simple, simply.
- Words ending in -ic add -ally: dramatic, dramatically; basic, basically. (Publicly is the exception.)
- Words ending in consonant + y change to -ily: angry, angrily.
Accidentally is one of the most misspelt words in English, because people say “accidently”. It's accidental + ly.
In the SATs
Suffix words are everywhere in the SATs spelling paper because so much Year 6 vocabulary is built this way. They matter even more in writing assessment, where words like stopped, beginning, happily and immediately come up in every piece of work.
Common mistakes
- stopedShould double: stopped.
- tryedConsonant + y: tried.
- dramaticly-ic words add -ally: dramatically.
- sincerlyKeep the e before -ly: sincerely.
Teaching ideas
Word sums
Write spellings as sums: hope + ing = hoping. Pupils explain what happened at the join and which rule applied. Making the join explicit is the key to all four rules.
Rule sort
Give pupils a mixed pile of root words and suffixes. They build the words, then sort them by rule: doubled, dropped e, y to i, or just added.
Stress test
For longer words, children clap the syllables and say where the stress falls. beGIN doubles; VISit doesn't. It's an advanced rule, but Year 6 pupils enjoy cracking it.
Proofreading hunt
Give pupils a paragraph from their own writing and ask them to find every word with a suffix, then check the join. This transfers the rules into independent writing, where they matter most.
Try it: five quick questions
SATs-style questions to use as a starter or a quick check. Tap to see each answer.
Add -ing to swim.
Show answer
swimming: one vowel, one consonant, so double.
Add -ed to carry.
Show answer
carried: consonant + y, so change to i.
Add -ly to gentle.
Show answer
gently
Add -ing to begin.
Show answer
beginning: the stress is on -gin, so double.
Which is correct? accidently / accidentally
Show answer
accidentally: accidental + ly.
Free worksheets for this topic
Printable A4 PDFs with answers. Free to use in class or at home.
