There is no fixed percentage; the comps decide what counts as reasonable. Fifty thousand off a five-million-dollar home is trivial; fifty thousand off a one-hundred-fifty-thousand-dollar home is a huge cut. The dollar figure means nothing until you turn it into a percentage and compare it to how homes are really trading in that specific area. Start with comps rather than a gut number. Look at recent sales (ideally the last 30 to 45 days) of homes that match on bedrooms, bathrooms, square footage, and location. That comparative market analysis tells you what the home is worth, and your offer should flow from it. In many normal markets homes sell within a few percent of list, so an offer well outside that band needs a real reason: either the home is genuinely overpriced or the comps back you up. Ignore the property tax assessment. It has essentially nothing to do with market value. And a home sitting longer than average can be nothing more than a seasonal slowdown. The reasoning behind your number matters as much as the number itself. If you can explain your offer with data, that strengthens your position in negotiation. If the number is simply what fits your budget, that is worth knowing too, but be honest with yourself about which it is. Lean on your agent to build and present the case, since a data-backed offer negotiates far better than an arbitrary one. Even then, a reasonable offer can get rejected by an unreasonable seller, and that is fine. You move on to the next one.