Recruiter asked for my expected number by email. Answer in writing or push it to a call? Negotiation

Answer in writing, briefly, with a range whose bottom is a number you would accept happily. Recruiters ask this to filter, not to trap, and refusing to answer at the screening stage mostly buys you a slower process and occasionally gets you dropped for being difficult. What you should not do is anchor on your current salary, and you are not obliged to share it. A sentence like "based on the scope described and comparable postings, I am looking in the region of X to Y" is enough and it takes the awkwardness out of the call later.

The push-it-to-a-call advice comes from a world where you can read a recruiter's reaction and adjust in real time, and some people are genuinely good at that. Most of us are not, and on a call you will get flustered and say a number lower than the one you wrote down. In writing you get to think for ten minutes and check your comparables.

If the posting had no band, ask them for theirs first, once, politely, in the same reply: happy to share where I am aiming, and it would help to know the range approved for the role. About a third of the time they will just tell you. That has been worth more to me than any phrasing trick.

Do not mention that your current salary is eighteen percent below your target, in writing or on a call. In several places asking for salary history is restricted anyway, and volunteering it hands over the only real leverage you have at this stage. Talk about the market for the role, not about your history.

Wrote back with a range last spring, got an offer at the bottom of it, and then successfully moved it up by about six percent by pointing at a specific responsibility in the job description that had not been in the screening conversation. Writing the range early did not cost me the later negotiation, which is the thing I had been afraid of.