Verbseoul.
ㄹ stem

덜다 conjugation (deolda, to subtract)

To say to subtract politely in the present tense, use 덜어요 (duh-ruh-yoh) · deoreoyo. Below is the full conjugation of 덜다 across the three tenses and three everyday speech levels.

Grammar note (ㄹ stem): ㄹ-stem verbs end in ㄹ as the final consonant. They are conjugated regularly with vowel suffixes (살다 → 살아요), but the ㄹ drops before certain consonant suffixes — specifically before ㄴ, ㅂ, ㅅ, and before the formal ending 습니다: 살다 → 사는, 삽니다, 살지 (ㄹ kept before ㅈ). This is sometimes called a "ㄹ drop" or "ㄹ irregular." See all ㄹ-stem verbs →

Conjugation table

pron. = pronunciation guide  · RR = Revised Romanization

Highlighted = where the stem changes

TenseCasual (반말)Polite (요)Formal (합니다)
Present
덜어
duh-ruh
deoreo
덜어요
duh-ruh-yoh
deoreoyo
덥니다
duhm-nee-dah
deomnida
Past
덜었어
duh-ruh-ssuh
deoreosseo
덜었어요
duh-ruh-ssuh-yoh
deoreosseoyo
덜었습니다
duh-ruh-sseum-nee-dah
deoreosseumnida
Future
덜 거야
duhl guh-yah
deol geoya
덜 거예요
duhl guh-yae-yoh
deol geoyeyo
덜 겁니다
duhl guhm-nee-dah
deol geomnida

Other useful forms

Honorific / Command Polite (-(으)세요)
더세요
duh-sae-yoh
deoseyo
Suggestion / Let's Polite (요)
덜어요
duh-ruh-yoh
deoreoyo
Question Polite (요)
덜어요?
duh-ruh-yoh-?
deoreoyo?
Connective "and" — (고)
덜고
duhl-goh
deolgo
Conditional "if" — (면)
덜면
duhl-myuhn
deolmyeon
Progressive (고 있어요)
덜고 있어요
duhl-goh ee-ssuh-yoh
deolgo isseoyo
Want to (고 싶어요)
덜고 싶어요
duhl-goh shee-puh-yoh
deolgo sipeoyo
Can / Able to ((으)ㄹ 수 있어요)
덜 수 있어요
duhl soo ee-ssuh-yoh
deol su isseoyo
Because / So (아/어서)
덜어서
duh-ruh-suh
deoreoseo
Noun form — (기)
덜기
duhl-gee
deolgi
Noun form — (음)
덞
duhm
deom