How long have you (been)?

This question form asks about the duration of an action or a state that started in the past and continues to the present. Use the present perfect simple or the present perfect continuous depending on the verb and the focus (state vs. duration/continuity).

• Use 'How long + have/has + subject + past participle' for states or completed actions that relate to now (present perfect simple).
• Use 'How long + have/has + subject + been + -ing' to emphasise ongoing actions or temporary activities (present perfect continuous).
• Answer with 'for' + period (for three years) or 'since' + point in time (since 2018).

Choose the form based on whether you emphasise a state or the ongoing action:

• Present perfect simple (have + past participle) = states, completed actions with present relevance: 'I have worked here for five years.'
• Present perfect continuous (have + been + -ing) = ongoing actions, temporary situations, or to stress duration: 'I have been working here for five years.'
• Use 'for' with durations (for three months) and 'since' with specific start points (since March).

If unsure, use the continuous to emphasise activity and the simple to emphasise state or result.

Watch for these universal errors when asking or answering duration questions:

• Using the simple past for actions that continue to the present: 'I worked here for five years.' (incorrect if you still work here)
• Confusing 'for' and 'since': use 'for' with periods (for two months) and 'since' with start points (since June).
• Mixing present perfect simple and continuous incorrectly: choose based on state vs ongoing action.
• Wrong word order in questions: remember 'How long have you + ...', not 'How long you have...'

Always check whether the action still continues when choosing the tense.