Dreamed vs. Dreamt
Main DifferenceDreamed and dreamt are both allowable past tense forms of the verb dream. Dreamt is often described as the British version of the word (1, 2, 3), however, a Google Books Ngram search shows that dreamed is more common than dreamt in both British and American English. Still, dreamt is on more equal footing in Britain than in America.

Difference Between Dreamed and Dreamt
Dreamed vs. Dreamt
Dreamt means Experience while sleeping (past tense of 'dream'), dreamed means conceived of or imagined or hoped for.
Dreamed vs. Dreamt
"Dreamt" is the past tense and participle of "to dream". "Dreamed" isn't a word. It's like when some people say "taked" nowadays for the past tense of "to take".
Dreamed vs. Dreamt
Dreamed is preferred in all main varieties of English as compared to dreamt.
Dreamed vs. Dreamt
Dreamt is especially common in British English; while American writers use dreamt about a tenth as often as dreamed, British writers use dreamt about a third of the time.
Dreamed vs. Dreamt
Dreamt is more often used in the figurative senses of the word, especially in the phrase dreamt up, while dreamed is more likely to denote the mental activity that occurs during sleep. But this is by no means a rule, and both words are used both ways.
Dreamed vs. Dreamt
Writers choose dreamt or dreamed depending upon their style of writing.
Dreamed vs. Dreamt
If you are excited about a dream you saw and discussing it with a friend, you would of course say that you dreamed about winning a lottery.
Dreamed vs. Dreamt
People believe that dreamt is a better option than dreamed that looks dull for a wonderful mental activity such as a dream.
Dreamed vs. Dreamt
Following grammar, Dreamed and dreamt are two forms of the past tense of dream, and there is no difference between the two.
Dreamedverb
simple past tense and past participle of dream
Dreamtverb
simple past tense and past participle of dream
Dreamedadjective
conceived of or imagined or hoped for;
his dreamed symphony that would take the world of music by stormDreamtadjective
or only extant in a dream or dreams.
What is Dreamed?
Dreamed means experiencing dreams during sleep or urging to imagine something. If you are excited about a dream you saw and discussing it with a friend, you would of course say that you dreamed about winning a lottery
What is Dreamt?
Dreamt is a simple past tense and past participle of dream. Dreamt is common in British English. Dreamt is more often used in the figurative senses of the word, especially in the phrase dreamt up.