Real Monte Carlo, real scale
Up to 10,000 paths per simulation, modeled with geometric Brownian motion and asset correlation. The same engine that powers institutional risk desks — calibrated for individual investors.
For iPhone
The honest answer to "will I have enough?"
Monte runs up to 10,000 Monte Carlo simulations on your real portfolio — actual tickers, real prices, your contributions and withdrawals — and tells you the probability you'll hit your goal. No spreadsheets. No black boxes. Every number is explained.
10,000
simulation paths per run
6,150+
U.S. securities supported
10 yrs
adjusted-close history per ticker
100%
on-device portfolio storage
Why Monte
The math your advisor uses, in your pocket.
Most retirement calculators give you one number from one assumption. Monte stress-tests your plan against thousands of futures — and shows its work.
Your tickers, not generic averages
Add real symbols — AAPL, VOO, QQQ, your 401(k) funds — and Monte pulls 10 years of adjusted-close price history. That means dividends and splits are baked in, so your "return" is the actual return you would have earned.
Stress-test against real history
Overlay your plan with the 2008 financial crisis, 1970s stagflation, the dot-com bust, or COVID. See exactly how much your probability of success moves when the world doesn't cooperate.
Glass-box, never black-box
For every result, Monte shows you the inputs: historical return, the forecast assumption it actually used, volatility per asset, and the full distribution of outcomes — not just a single average.
Contributions, withdrawals, inflation
Model the full life cycle — monthly contributions during accumulation, inflation-adjusted spending in retirement, Social Security, and Smart Spend dynamic withdrawal logic.
Private by design
Your portfolio lives on your device — not a server we own. No account to create, no brokerage logins, no data sold or shared. Only the ticker symbol leaves your phone, and only to look up its price.
Feature tour
From "I think I'm okay" to "I have a 81% probability."
Every screen below is the real app, running a real plan. No mockups, no marketing renders.
Step 1 · Build it your way
Your portfolio. Down to the last share.
Search 6,150+ U.S. stocks, ETFs, bonds, and mutual funds. Add real share counts and monthly contributions, and Monte tracks total balance and dollar-weighted exposure as you go. No account linking, no read-only OAuth, no surprise data sharing.
- Real tickers with company names and adjusted-close history
- Per-holding monthly contribution schedule
- Live total value and weight calculation
Step 2 · Run thousands of futures
A real probability of success. Not a vibe.
Monte simulates up to 10,000 month-by-month paths through retirement — accumulation, drawdown, inflation, Social Security, the works. You get one number that actually means something: the share of futures where your money outlasts your spending.
- Up to 10,000 paths per run
- Sustained vs. depleted breakdown — no hidden buckets
- Smart Spend dynamic withdrawal comparison built in
Step 3 · See the math
Every assumption, on the screen.
Other apps hide their inputs. Monte shows you, per ticker, the historical return, the forecast Monte actually used, and the volatility — so you can sanity-check the model before you trust the answer. Then it gives you the best, median, and worst case at retirement, in today's dollars.
- Historical vs. forecast return for every holding
- 10th / 50th / 90th percentile portfolio values
- Inflation-adjusted "real-dollar" projections
Step 4 · The full distribution
Watch your range of futures unfold.
Most calculators give you a single line. Monte gives you the fan: the 25–75% band, the 10–90% band, and the median path — all the way through retirement. Toggle between linear and log scale to see what's really driving long-term outcomes.
- Percentile bands across 5,000–10,000 simulated paths
- Real-dollar (inflation-adjusted) values
- Linear and log views for tail-risk inspection
Step 5 · Stress-test history
What if 2008 happened again — right at retirement?
Inject real historical crises into your plan and see what happens. Each overlay is calibrated from actual return data and shows you the impact on your probability of success and the long-term cost to your median balance — all on top of your existing simulation.
- 2008 Financial Crisis, dot-com bust, stagflation, COVID
- Choose when the overlay hits — early career, mid-career, start of retirement
- Side-by-side probability and median-balance impact
Pricing
Start free. Upgrade when you need more.
One free tier with everything most people need. Pro and Max unlock deeper analysis for serious planners.
Free
$0
- One saved portfolio
- Up to 1,000 simulation paths
- Real ticker data, adjusted close
- Core probability + percentile results
Most popular
Pro
$4.99 / month
- Unlimited saved portfolios
- Up to 10,000 simulation paths
- Economic scenario overlays
- Side-by-side plan comparison
- Smart Spend dynamic withdrawals
Max
$9.99 / month
- Everything in Pro
- Custom asset correlation models
- Tax-aware withdrawal modeling
- Priority support
Ready to know your odds?
Monte is free to download. Run your first simulation in under five minutes.
Download on the App Store