Every calculator is a scratchpad. Type into it freely, whether or not a deal is attached, and nothing you enter is saved to a record unless you deliberately export it.
What the Scratchpad Is For
Use the calculators to run numbers for someone who is not yet a client in your system, to test a range of outcomes on someone who is, or to sanity check an offer before you take it to a deal. Nothing you type is written to your database as you go, so you can run a scenario, throw it away, and run another without leaving a trace.
Why Nothing Writes Back to the Deal
Attach a deal and the calculator prefills its starting values, but every value after that lives only in the calculator. Change the rate, stretch the amortization, or add a debt, and the deal record underneath does not move. This holds whether or not a deal is attached: the calculators are a scratchpad first, and attaching a deal is only a fast way to fill one in.
Carrying Figures Between Calculators
Amortization, prepayment, offset, Explain My Mortgage, cash damming, and fixed vs variable all share one typed mortgage: balance, rate, amortization, and property value. Enter these once in any of them and the rest pick up the same numbers when you switch, so comparing two strategies on the same file does not mean retyping the mortgage each time.
Keeping a Result You Want
The scratchpad itself keeps nothing once you leave the page. To hold on to a result, use Copy summary for a quick text version or Preview & Export for the branded document, both covered in Copy or Export a Calculation. The Mortgage Plan and Prepayment Penalty calculators are the exception, since each keeps its own short history in your browser so you can flip back between recent runs.
When the Scratchpad Resets
Switching between calculators mid-session keeps your shared mortgage figures in place. Attaching a deal seeds those figures from the deal once; if the deal's own numbers change afterward, you see a note that the two have drifted and can reset to the deal's current figures without losing anything else you typed. Leaving the calculators page, or attaching a different deal, clears the scratchpad back to defaults or to the new deal's own numbers.
What to Do Next
Attach a deal to seed a calculator with real figures in Prefill a Calculator From a Deal, or open Choose the Right Calculator if you are not sure which one answers the client's question.