從語義上看，but所表示的是非常明顯的對比，轉折的意味較however要強。從語序上看，but總是位於所引出的分句之首，而however卻可位於句首、句中和句末。從標點符號上看，but之後壹般不得使用逗號，而however則必須用逗號與句子其它部分分開。
but和however區別例句
(1)I thought those figures were correct.However,I have recently heard they were not.我原以為那些數字正確無誤，不過我最近聽說並不正確。
(2)Eat to live , but do not live to eat.吃是為了活，不要活著為了吃。
however的用法1.however作副詞用時，表示“然而；但是”，可位於句首、句中和句末；位於句首的時候，要用逗號和其他句子部分隔開；位於句中的時候，其前後都要用逗號；位於句末的時候其前用逗號分開，例如：
(1)She felt ill.She went to work,however,and tired to concentrate.她生病了。然而她仍去上班，並且盡力集中精神工作。
(2)His first response was to say no.Later,however,he changed his mind.他最初的反應是不同意，可是後來他改變了主意。
2.however可以作連詞，表示“無論以何種方式，不管怎樣”，引導讓步狀語從句。例如：
(1)You can travel however you like.妳可以隨心所欲地去旅行。
(2)However I approached the problem，I couldn’t find a solution.這壹問題我不管怎樣都無法解決。