NEVER Disclose Your Current Salary To A Potential New Employer!
If the employer wants to know what is the market value for that role, there are plenty of resources to find out.
ALWAYS try to make the employer give you a number. If it’s higher than what you expect, well that’s good for you (even then, you probably have room to squeeze a bit more in the negotiation process. Or some vacation days. Or other perks.). If it’s lower than what you expect, try to negotiate (if they have no room to negotiate, then don’t waste your time with them).
Your current salary is not the new employer’s business. You could be working pro bono, just because you like it there. That’s none of their concerns.
They’re buying your skills, which are open to negotiation. You could be selling them for a lower or higher price, depending on how good of a negotiator you are. Your new client may value your skills more than other clients, depending on how good of a match you are for the job description and other factors.
Oh… did I mention NEVER disclose your current salary? Yeah, don’t do that. (Unless you are a consultant, working with a recruiter and he/she needs to know what is your hourly rate. But even then, it is not really necessary, just say the minimum hourly rate you are willing to work for, and you can go from there.)