ましょうか

ましょうか is a polite offer or suggestion: "shall I…?" or "shall we…?". Take a verb in its ます-form and change ます to ましょうか.

Shall I or shall we

Japanese marks neither "I" nor "we" here; the situation does. When the action helps the listener – carrying, opening, calling a taxi – it is an offer. With a question word such as なん何, どこ or いつ, it is almost always "shall we".

To accept an offer, say おねがいしますお願いします. To turn it down, say いいえ、だいじょうぶ大丈夫です.

ましょうか or ませんか

ませんか asks whether the listener wants to do something, so it suits a first invitation. ましょうか proposes something you are both already part of and asks whether now, or this, is the moment.

Not ～てほしいですか

English offers with "do you want me to…?". ×窓を開けてほしいですか and ×手伝ってほしいですか ask about the listener's wishes and sound odd as an offer. Use ましょうか.

• × 手伝ってほしいですか → 手伝いましょうか