In the realm of $10M+ homes 99% of the time it will be through referrals from past customers. I know they're not going to waste my time nor theirs if the wherewithal to purchase doesn't exist. There is a formula, however, a "net worth calculator" is not the proper tool and may quell many opportunities.

Kevin J. May said it well, and they have private bankers.  You don't need a calculator.  A

Need more data.

It's not so much the net worth, it's rather access to capital and that might mean a decent credit score and good cashflow. 

Not sure that there is any set aprameters by which to judge.

You have lots of answers here James Hoff 

I don't know if I would trust anythinglke htat.

I would have no idea how to go about calculationg that. 

I have a HP 10b11+ Financial calculator..If I knew how to fully operate it, I may can help you get that answer - but since I don't you are right back where you started..

Not going there..have them call a loan officer

That's a call to my loan officer who has to stay up nights answering

Not sure that there is any set aprameters by which to judge.

Those buyers looking at a $10m home usually are cash in my area.

I think Fidelity has one.  I'm not sure I understand how you are going to use this info though. -Kasey

James Hoff - you have the best answer from Kevin J. May.

I have a good spreadsheet and know how to use it well.

A simple net worth calculator is using a spreadsheet.  That's what I used for a long time to track mine.

What Kevin J. May said.

Kevin May said it well!

I am not sure the application of a net worth calculator will get you what you want ... or even close to it. 

No.

This one is a mystery for me. I'll stick around to see what others say.

Not sure that I can help.  Perhaps a discussion with a lender?

I have a spreadsheet with lots of calculations but that is not one of them - that would be up the investor to figure out with their lender

use a regular calculator

As with any price range, i go about it the way you would qualify any new buyer with income and ratios. When difficult, i let one of the good local and trusted loan officers pre qual them

I don't have a clue.

Let us know what you figure out.  

Forbes I'm sure.

Huh?

Nope.

Alan May nailed this one!

I stopped by, thanks for the feed back

If you have access to ZipForms, they have a net sheet that does the calculations for you when you plug in the values.

Our CA zipforms offer such forms for sellers, you can use it for a future purchase to input all your future expenses if it is a flip. 

Try to see about an MS Excel calculator template from Microsoft.