The success rate

The single most important number in your plan — and the reason Vundii runs your retirement 6,000 times instead of once.

In plain English

Your success rate is the percentage of 6,000 simulated versions of your retirement in which your money lasted your whole life. 82% means: in 82 of every 100 plausible futures, you never ran out.

Why not just one projection?

A simple calculator assumes your investments earn, say, 7% every single year like clockwork. Real markets don't do that — they return +26% one year, −18% the next. And it turns out the order of those good and bad years changes your outcome enormously, even when the average is identical.

So instead of pretending to know the future, Vundii generates 6,000 different ones — each a full retirement's worth of randomized market returns based on historical behavior. Some futures start with a crash. Some catch a long bull market. Some grind through years of high inflation. Your plan is tested against all of them.

Example: Two retirees each start with $1M and withdraw $50K a year, and the market averages 7% over their retirements. One hits a crash in year two and recovers later; the other gets the same crash in year twenty. The first can run out of money in their 80s while the second finishes with more than they started. Same average return — completely different lives. One projection can't show you this; 6,000 can.

What the number should mean to you

85%+ — strong. Your plan survives most futures, including many that begin badly. Chasing 100% usually means underspending a retirement you saved decades for.
70–84% — workable, but thin. A modest change — retiring a year later, trimming spending, saving a bit more — typically moves this range up quickly.
Below 70% — pay attention. Roughly one in three futures ends with money running out. Better to know now, while every lever is still available.

One misconception worth killing: a "failure" in a simulation isn't a cliff. It means that in that scenario, your spending would have needed to come down at some point. Real people adjust — which is exactly what adaptive spending strategies model (see Market risk & sequence of returns).

What Vundii shows you

The Dashboard shows your headline success rate. The Projections page shows where it comes from — a fan chart of all 6,000 futures:

The dark center line is the median: half the futures did better, half worse.
The upper band (90th percentile) is what very lucky markets look like.
The lower band (10th percentile) is the unlucky path — this is the line your plan should survive.

Toggle "Real (inflation-adjusted)" to see everything in today's purchasing power. $1M twenty-five years from now buys what roughly $480K buys today at 3% inflation — the real view is the honest one.

What to do about it

Look at your success rate on the Dashboard. Don't panic at any single number — it moves as your inputs improve.
On Projections, find the 10th-percentile band. If it stays above zero through your planning horizon, weak markets don't break you.
If the number disappoints, test the three big levers in Scenarios: retire later, spend less, save more. You'll usually be surprised how little it takes.
Check the Inflation Sensitivity Grid to see how your rate holds up if inflation runs hotter than expected.

See your own success rate in about 10 minutes.

Try it in Vundii →