Estimate the landowner's share in a land-for-units deal (the landowner gives the land and takes units of the building) with the residual value method: project revenue minus construction cost and developer profit leaves the land's contribution. Your own figures, in your own currency. Free, no sign-up.
Honest note: this is an approximate pre-assessment, not an official valuation or a zoning certificate. The residual method is sensitive to its inputs — negotiate with ranges, not a single number.
Don't guess the FAR. In the RONCHAMP panel, query your parcel — setbacks and FAR come from the official source, and the engine produces real, rule-verified floor plans for your lot (not a text scenario).