Datumline methods

Real Estate Calculations

every metric the inputs support, every missing one named, no defaults

The problem

Underwriting spreadsheets quietly assume: vacancy defaults to 5%, other income to zero, a missing expense line to last year's. The outputs look complete, so nobody notices which numbers were never supplied. Broker teasers make it worse: a cap rate on a page with no expense figure behind it.

What it is

A schema-driven property calculator that computes every metric its inputs support, names every metric it cannot compute and why, and never fills a gap with a default.

Delivered as a download: method documents, templates and standard-library Python scripts with tests that fail when the method's own logic is broken. Synthetic example data only.