What is Chance of Success?
Chance of Success is a percentage. It tells you how many of your possible futures end with money left over.
It's not a grade. It's not a prediction. It's a way to see how your plan holds up when the future doesn't go exactly to plan - because it never does.
Why a single projection isn't enough
A standard projection uses one assumed rate of return, applied every year, forever. It's useful for seeing the shape of a plan, but it hides something important: real markets don't move in a straight line. Some years are strong, some are weak, and the order those years happen in matters more than most people realise.
Two plans with the same average return can end up in very different places depending on when the bad years hit.
How Canwi calculates it
Instead of running your plan once, Canwi runs it [X,000] times.
Each run uses a different, randomly generated sequence of investment returns - some better than average, some worse, most somewhere in between. This is called a Monte Carlo simulation.
A run counts as a success if your projected balance stays at $0 or above through to the end of your plan. It doesn't matter if you finish with $50,000 or $2 million - both are a success. It also doesn't matter if your balance dips low at some point along the way, as long as it recovers by the end (say, after a property sale or an inheritance).
Your Chance of Success is simply the share of runs that succeeded. If 750 out of 1,000 runs end at $0 or above, your Chance of Success is 75%.
How to read your number
A lower number doesn't mean your plan fails. It means there's a chance you'll need to adjust something, at some point, if markets underperform.
A 70% Chance of Success roughly means: in 3 out of 10 futures, you'd need to make a change somewhere along the way - cut back on discretionary spending for a year or two, delay a big purchase, sell illiquid assets, or skip a planned increase in spending. It doesn't necessarily mean running out of money with no options.
The more flexible you're willing to be, the more comfortable you can be with a lower number.
There's no universal "good" score
A 95% Chance of Success sounds safer than 70%. But a very high number can also mean you're over-saving or under-spending relative to what you actually need - money that could have gone toward the life you're trying to fund.
What's "right" depends on you:
How much of your spending is essential versus discretionary, and how easily you could cut the discretionary part
Whether you want to leave money behind for kids or other people
How much certainty you need to feel comfortable, versus how much you're willing to adjust along the way
Someone with no dependents and no inheritance goals might be perfectly comfortable at 65%. Someone who wants to guarantee a legacy might aim higher.
What to do with your number
Use it as a prompt to check your plan, not a final verdict.
Are your return and inflation assumptions realistic?
If markets had a rough decade, is there anything you could actually adjust?
If the answer to that last question is yes, a lower Chance of Success is less of a worry than it looks.