Converting back to your home currency is the single most common mistake in this exact situation, so you're already ahead just by knowing to avoid it. The number only means something in terms of local purchasing power — what rent, groceries and transport actually cost where you're moving, not what they'd cost back home.
The price guide on each country's page is built exactly for this — it gives you a real sense of local costs so you can sanity-check an offer against actual local life rather than a currency conversion. Worth doing that before you send your counter.