Tool · Browser-only · US + Canada
Bi-Jurisdictional Monte Carlo Retirement Withdrawal Optimizer
A free interactive tool for retirement decumulation planning across two jurisdictions. Models bucket-by-bucket withdrawal sequencing, mandatory distributions (RMD & RRIF), dividend tax channels (eligible / non-eligible / qualified), corporate passive investing (Holdco / C-Corp), leveraged investing (Smith Manoeuvre / I.R.C. §163(d)), and Safe Withdrawal Rate frontier across confidence levels.
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What it does
Comprehensive retirement decumulation modelling for both US and Canadian retirees
Most retirement calculators use a single-jurisdiction tax engine, ignore mandatory distributions and government-benefit clawbacks, and treat capital-gain and dividend income identically. This simulator addresses all of those gaps with statutory-citation-grade implementation across both jurisdictions.
Bi-jurisdictional tax engines
Full US federal (Rev. Proc. 2024-40 brackets) + 5 state engines (CA, NY, MA, IL, NJ) with NIIT, FICA, Social Security provisional-income method. Full Canadian federal + 4 provincial engines (ON, BC, AB, QC) with surtax, OAS recovery, eligible / non-eligible dividend channels.
Mandatory distributions
IRS Uniform Lifetime Table per Treasury Reg §1.401(a)(9)-9 (extended to age 120). CRA Prescribed Factor Table per Income Tax Regulations s.7308(4). SECURE Act 2.0 §107 RMD start age 73. Pre-71 RRIF voluntary conversion supported via the 1/(90−age) formula.
Holdco / CCPC modelling
Corrected dividend-only inside drag (capital appreciation compounds tax-free until realisation). Pipeline extraction at death via ITA s.70(5) + s.84.1-compliant Newco structure (~26.77% effective Ontario) versus annual non-eligible dividend distribution (~47.74% top Ontario).
US C-Corporation modelling
Three extraction modes: W-2 salary (deducts at corp, ordinary + FICA at personal), qualified dividend (LTCG-rate + 3.8% NIIT + state ordinary), and defer-to-death (I.R.C. §1014 basis step-up assumption).
Leverage modelling
Personal Non-reg, Holdco, or split leverage per ITA s.20(1)(c). Interest deductible against investment income. Models the dividend-tax wipeout, the (μ−i) windfall return, and the variance amplification that hurts the worst-decile (P10) wealth.
Dividend yield split
Eligible Canadian dividends (1.38× gross-up, 15.0198% federal DTC, provincial DTC, surtax-aware) versus non-eligible (1.15× gross-up, 9.0301% federal DTC). US qualified dividends taxed at federal LTCG rates + 3.8% NIIT.
Safe Withdrawal Rate frontier
SWR computed via bracket-and-binary search across confidence levels {50%, 70%, 80%, 85%, 90%, 95%, 99%}. Distinguishes "success rate at your spend" from "spending level that meets your target."
Cross-country bucket equivalence
Switching US/CA preserves user-entered values via semantic mapping (Taxable ↔ Non-reg, Trad ↔ RRSP, Roth ↔ TFSA, HSA ↔ FHSA, C-Corp ↔ Holdco, Social Security ↔ CPP). Per-country edits stick across subsequent toggles.
Validation
Every tax rate validated against published sources to basis-point precision
The tax engine has been audited against CRA, IRS, KPMG, and EY published rate tables. Selected validation points:
| Rate / table | Model output | Source |
|---|---|---|
| Top Ontario combined ordinary | 53.53% | CRA / KPMG 2025 tax facts |
| Top Ontario capital gain effective | 26.77% | ITA s.38(a) × 53.53% |
| Top Ontario eligible dividend | 39.34% | CRA / EY 2025 tax facts |
| Top Ontario non-eligible dividend | 47.74% | CRA / EY 2025 tax facts |
| IRS RMD divisors ages 73–120 | All exact | Treasury Reg §1.401(a)(9)-9 |
| CRA RRIF factors ages 72–95+ | All exact | Income Tax Regs s.7308(4) |
| NIIT | 3.8% | I.R.C. §1411 |
| US top federal qualified dividend | 23.8% | I.R.C. §1(h)(11) + §1411 |
| CCPC eligible inter-corp dividend | ~0% net | ITA s.112 (perfect integration) |
| Holdco pipeline rate (Ontario) | 26.77% | ITA s.70(5) + s.84.1 |
Critical findings
What the model surfaces that simpler tools miss
| Question | What the model shows |
|---|---|
| Does leverage help me? | Median terminal wealth rises with leverage (positive μ−i spread compounds), but Safe Withdrawal Rate falls because variance amplification dominates the worst-decile. Leverage is a legacy tool, not a spending tool. |
| Should I extract from Holdco via pipeline or annual dividend? | Pipeline saves ~15–20 percentage points of effective rate at top Ontario (26.77% vs 47.74%) and allows tax-free compounding inside the corp for the full horizon. Combined effect: typically +15–30% terminal wealth. |
| Is the inside-corp drag really 30% on everything? | No — drag applies only to the dividend portion of returns. Unrealised capital gains compound tax-free per ITA s.38(a). Eligible Canadian dividends face ~0% net drag via s.112 inter-corp deduction. Bond interest faces ~50%. |
| How much does OAS actually help me? | Depends entirely on portfolio size. At $1.2M: ~$8,125/yr of $8,700 face value (7% clawback). At $3M: $6,356 (27% clawback). At $5M: net-negative ($-7,945 — OAS triggers tax distortions). At $10M: $0 (100% clawback). |
| What's the cost of holding US dividend stocks in Non-reg? | Foreign dividends face full ordinary tax (~53.5% top ON) + 15% US withholding (partly recoverable via FTC). Versus eligible Canadian dividends at 39.34% top ON, a holding-location decision worth ~14pp of dividend rate. |
| Does the SWR change with my dividend yield assumption? | Yes — by ~$2,300/yr per 2% yield over 25 years (US qualified dividend) and ~$3,000/yr (CA eligible dividend at typical retiree income). The tax-deferral compounding benefit of capital appreciation is materially eroded by annual dividend taxation. |
Important caveats
What this tool is — and what it isn't
This is a planning aid, not financial or tax advice. The model is best used to build intuition about how different parameters and structures interact. Outputs depend on user inputs and assumptions; results are not predictions. The methodology section in the interactive tool dynamically renders the calculation specifics for your inputs along with antithesis caveats flagging known simplifications.
Specifically not modelled (selected list): spouse-age election for RMD/RRIF, Roth conversion ladder optimisation, pension income splitting, tax-loss harvesting, margin-call forced liquidation, variable-rate borrowing exposure, fat-tail return distributions, ETF expense ratios, advisor fees, US LIRA / LIF differences, inherited IRA SECURE Act 10-year rule, Personal Holding Company tax (I.R.C. §541), and Accumulated Earnings Tax (I.R.C. §531-537).
Consult a licensed CPA, CFP, or tax attorney before making decisions that depend on these computations. The author is not licensed and provides no warranties of accuracy or fitness for any purpose.
See also
The companion research note tests whether a personal passive-index portfolio actually outperforms institutional pensions and endowments. The retirement optimizer above uses the conclusions of that note for its default return and volatility assumptions.