A Monte Carlo simulation of your financial future
Define your model in main.py. This determines your income, expenses, saving, investments, mortgage, retirement date, and in general the rules for how money flows between your accounts. Then it runs your model each month over the next however many years, keeping track of each deposit, transfer and withdrawal. NYC (+ state and federal) income taxes are also included as an example.
Each simulation run uses a different randomly generated set of market returns. You can have it run 100 simulations and summarize the results, reporting on the various percentiles of outcomes after each decade.
Sample report:
2030 10% 20% 50% 80% Mean
Investments: $1,666,844 $1,767,942 $2,060,005 $2,339,828 $2,057,202
Retirement: $1,672,445 $1,977,891 $2,729,116 $3,798,156 $3,032,895
Real estate: $671,129 $678,578 $693,484 $709,427 $693,844
2040 10% 20% 50% 80% Mean
Investments: $2,461,642 $2,744,543 $3,320,069 $3,995,028 $3,392,655
Retirement: $2,723,549 $3,716,723 $6,080,778 $9,449,286 $7,191,910
Real estate: $1,119,091 $1,126,538 $1,143,893 $1,166,355 $1,146,240
2050 10% 20% 50% 80% Mean
Investments: $4,662,784 $5,018,233 $6,404,925 $8,116,520 $6,512,778
Retirement: $1,409,481 $2,623,490 $6,327,954 $16,685,415 $9,869,389
Real estate: $1,656,798 $1,674,842 $1,711,933 $1,751,333 $1,711,884
2060 10% 20% 50% 80% Mean
Investments: $6,589,623 $7,920,665 $10,258,782 $14,687,034 $10,852,437
Retirement: $403,675 $599,027 $8,124,133 $36,454,233
59E1
$20,427,453
Real estate: $2,008,117 $2,031,506 $2,086,502 $2,134,982 $2,085,793
2070 10% 20% 50% 80% Mean
Investments: $6,370,397 $9,237,611 $16,162,112 $22,207,417 $15,851,272
Retirement: $586,773 $1,003,030 $13,777,765 $57,625,401 $38,380,464
Real estate: $2,441,272 $2,468,178 $2,544,700 $2,624,596 $2,499,399
If you want to peek at the details, the complete ledgers for all accounts for a single run of the simulation get saved to the ledgers/ directory, showing each withdraw, deposit and transfer.
$ head ledgers/checking
Year Mo Note Amount Tax Balance
2021 1 Transfer from Income $13,357.14 - $39,357.14
2021 1 Credit card $-3,633.40 - $35,723.75
2021 1 Nanny $-2,675.72 - $33,048.03
2021 1 Travel $-1,281.24 - $31,766.79
2021 1 Transfer to Mortgage 1A $-1,144.63 - $30,622.15
2021 1 Transfer to Merrill $-10,622.15 - $20,000.00
2021 2 Transfer from Income $26,737.94 - $46,737.94
2021 2 Credit card $-2,773.94 - $43,964.01
2021 2 Nanny $-2,499.10 - $41,464.90