Not original poster but I've played around with this scenario using
cfiresim.
You can plug in a future retirement date, and pick your plan end (I normally set to the year the younger spouse will be 100).
To keep things simple you enter current portfolio and then projected annual spend which can be absolute dollars (today's dollars and select adjust for inflation) or percent of portfolio.
You can enter in social security and any pension assumptions or you can leave those out to see how only your existing portfolio will grow over time. You can also add in 1x expenses like college, basically you can get as detailed or high level as you want. For portfolio assumptions you can use historical market data, fixed percentage, or several other options.
Here's 1 random example:
Retirement year: 2041
Plan end: 2080
Starting Portfolio: $1m (no further contributions)
Historical market data
75/25 equities/bonds
Annual Spend in retirement (starting 2041): $80k. Adjusted for inflation.
100% success.
Avg portfolio at retirement: $3.1m
Highest portfolio: $33m

Lowest $0.6m (using data from 1929, not a great year to retire but portfolio would have survived)
Link to simulation above:
https://www.cfiresim.com/a27c3bc0-b277-4084-9041-2be55ab685ce