"Before Enough, I didn't think we had surplus. Not only do we have surplus, but even if we increase our philanthropic giving, our kids will be okay. It's given me huge confidence that we can be bolder in giving more." — Wendy
This free Enough Simulation Tool can help you get a feel for how much is enough for you, based on your own needs. Note that the link above will ask you to make your own (free) copy, so the spreadsheet will become yours and is totally private.
A spreadsheet can never replace sophisticated financial planning, as it can't capture all the complex nuances of different return rates, taxes, etc (without getting really complex). However, the goal of this spreadsheet is to provide users with a simple way to get a first rough approximation, which can then be used as a basis for going into more detail.
This Enough Simulation example can serve as a guide on how to fill in the Enough Simulation tool.
The example case also shows what happens in three scenarios:
'Keep Accumulating' - just personal / family consumption, with little philanthropy
'Maintain Wealth Level' - maintaining lifestyle, whilst increasing philanthropy to preserve the wealth roughly at the current level (not growing it)
'Ambitious Surplus Deployment' - maintaining lifestyle, whilst increasing philanthropy to gradually reduce wealth to an end of life target