Eight calculators
One question each, answered properly
Separate pages, because these are the most linkable things on a mortgage site and deserve to be destinations. Live recalculation, month and year views, graphs that read in both themes, and a link you can copy that carries your numbers with it.
How they behave
The same rules on every one
- They recalculate as you type. No submit button, and sensible defaults so the page is useful before you touch anything.
- The inputs are the URL. Copy the link and it reopens with your numbers. That is the primitive the sharing and the email fallback are built on.
- Every assumption is on the page and editable. Including the ones most calculators bury, like the expense factor and the vacancy allowance.
- Graphs never rely on colour alone. Each series carries a dash pattern and a label drawn at the end of its own line, and each reads in both themes and under every palette.
- Long tables scroll inside themselves. The page does not scroll sideways at any width, and every control is at least 44 pixels.
- Mortgage insurance follows the programme. Conventional PMI ends at 78% of the original value; FHA does not; USDA runs for the life of the loan; VA charges none. Getting that wrong understates the answer by five figures.