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What assumptions and inputs go into Retirement Planning and Monte Carlo simulations?

PortfolioPilot's retirement planning engine is built on a detailed financial model - not a single return assumption. Monte Carlo simulations run on a wide range of structured inputs that reflect your personal situation, portfolio composition, tax context, and planning preferences.

The system incorporates multiple categories of inputs:

1. Personal & Timeline Inputs

  • Current age
  • Retirement age
  • Life expectancy
  • Social Security start age
  • Inclusion of spouse/partner (modeled separately if selected)

2. Contributions & Savings Behavior

  • Monthly retirement contributions
  • Monthly taxable investment contributions
  • Max-out yearly Roth contribution (Yes/No)
  • Portfolio rebalance frequency

3. Income & Retirement Cash Flow

  • Social Security annual benefit
  • Pension and other retirement income
  • Lump-sum pension payout at retirement
  • Yearly taxable income (pre-retirement)
  • Monthly retirement budget (inflation-adjusted)

4. Current Asset Base

  • Starting tax-free assets
  • Starting tax-advantaged assets
  • Starting taxable assets
  • Consolidated connected accounts across investment types

5. Risk & Return Assumptions

  • Pre-retirement return rate
  • Retirement return rate
  • Risk preference (pre-retirement)
  • Retirement risk preference
  • Volatility modeling aligned with portfolio structure
  • Correlation assumptions across asset classes

6. Tax Modeling Inputs

  • Tax filing status
  • Country of residence
  • State/province of residence
  • Tax loss harvesting frequency
  • Withdrawal strategy (including tax-efficient sequencing)
  • Required Minimum Distributions (RMDs) modeling
  • Portfolio management fee assumptions

7. Inflation & Economic Assumptions

  • Inflation rate (YoY)
  • Salary growth rate (YoY)
  • Macroeconomic forecast overlays within portfolio projections

8. Life Events & Irregular Cash Flows

Users can model one-time or recurring events such as:

  • Down payments
  • College tuition
  • Home improvements
  • Marriage or divorce
  • Big trips
  • Long-term care
  • Medical expenses
  • Reverse mortgage
  • Inheritance
  • Selling a business
  • Severance
  • Insurance proceeds
  • Charitable contributions
  • Roth conversions
  • Family support
  • Custom events

Each event can include:

  • Date range
  • Amount
  • Directional wealth impact

How Monte Carlo Uses These Inputs

Monte Carlo simulations generate thousands of potential market paths using modeled return distributions, volatility assumptions, and macro-informed forecasts. Each simulation path reflects:

  • Your contribution schedule
  • Asset allocation and risk level
  • Tax treatment across account types
  • Withdrawal sequencing
  • Inflation adjustments
  • Modeled life events

Rather than producing a single deterministic projection, the system estimates probability distributions of retirement success under varied market conditions.

The result is a multi-layer retirement model grounded in:

  • Portfolio mathematics
  • Tax-aware cash flow modeling
  • Macroeconomic assumptions
  • Personal behavioral inputs

Outputs are hypothetical and for analytical purposes. Actual outcomes will vary based on market conditions and individual decisions.

How optimized is your portfolio?

PortfolioPilot is used by over 40,000 individuals in the US & Canada to analyze their portfolios of over $30 billion1. Discover your portfolio score now:

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1: As of November 14, 2025