Question 1

When do I double the last letter before adding -er?

Accepted Answer

Double the final consonant when a one-syllable adjective ends in consonant + short vowel + consonant: "big" → "bigger" (b-i-g), "hot" → "hotter" (h-o-t), "thin" → "thinner" (th-i-n), "sad" → "sadder" (s-a-d), "wet" → "wetter" (w-e-t). Do not double when the adjective ends in two consonants: "fast" → "faster" (not "fastter"), "old" → "older" (not "oldder"). Do not double when there are two vowels before the consonant: "cheap" → "cheaper" (not "cheapper"), "cool" → "cooler" (not "cooller"). This short-vowel doubling rule also applies when adding -est, -ing, and -ed to words. Cambridge A2 Key and B1 Preliminary both test these spelling patterns regularly in their writing sections.

Question 2

How do I add -er to adjectives ending in y?

Accepted Answer

When a two-syllable adjective ends in -y, change the y to i and add -er: "happy" → "happier," "easy" → "easier," "funny" → "funnier," "busy" → "busier," "dirty" → "dirtier." This rule applies because English avoids the double letter combination "ye" before a suffix. The same change happens with superlatives: "happiest," "easiest," "funniest." Be careful — this rule only applies to adjectives ending in a consonant + y. Words ending in a vowel + y keep the y: "grey" → "greyer" (not "greier"). Mastering the y-to-i rule helps with other word forms too, like "carry" → "carried."

Question 3

What happens to adjectives ending in -e when I add -er?

Accepted Answer

When an adjective already ends in -e, simply add -r (not -er): "nice" → "nicer," "large" → "larger," "wide" → "wider," "safe" → "safer," "late" → "later." This avoids a double e: "niceer" would look wrong, so we write "nicer." For superlatives, the pattern is the same: add -st instead of -est: "nicest," "largest," "widest." This is one of the simpler spelling rules because it only removes one letter. If you remember that English avoids doubled vowel letters in suffixes, the rule makes sense. Cambridge A2 Key and B1 Preliminary both test these spelling patterns in the writing sections.

Comparative Spelling Changes Exercises

Quick Rule

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Comparatives and Superlatives Error Correction

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As...As Structures

-ed vs -ing Adjectives

Conditionals

Present Perfect