JRTN Tool

JRTN is a Microsoft Excel based tool. The core of the tool is a model spreadsheet that fully exposes the calculations associated with annual spending determination. Available spending is ultimately controlled by external income sources and by draws against various accounts (and of course by income taxes). The draws are captured as a few input columns in the model spreadsheet. Automation is provided to adjust the draws to meet after tax spending needs. This requires an iterative solution approach because there is no reasonable closed form solution. A user can avoid the automation completely and manually set the draws if desired. This might be a first step at using JRTN to “build their own worksheet.” Substantial additional automation supports activities such as scenario comparison, maximum spending calculation, Roth conversion optimization, etc.

The user interface is forms-based, however the user is required to populate input data such as account values, expected rates of return, etc. directly into a spreadsheet.

The central notion for JRTN is that we need to look at multiple scenarios to make our choices and to understand possible future outcomes. For example, we should look at both low and higher inflation levels, low and higher rates of return, etc. JRTN has rich scenario support including the automatic Scenario generation via permutation of control parameters, scenario summaries, and graphical scenario comparison.

• Automatic draw calculation to reach specified after-tax spending
• Automated Scenario Generation – generate 1000s of scenarios by permuting parameters such as inflation, ROI, SS commence
• Both independent and dependent parameters for scenario generation. For example, you can tie “moving to a different State” with “change in expenses.”
• Maximum Spending Calculation
• Roth Optimization and Analysis Tools
• Social Security Break-Even
• Single and Married Retirees
• Support for potential Federal tax law changes
• Support for State Taxes
• Configurable State Tax rules. This is done via a worksheet that specifies rules for each state, so users typically just pick the state
• Support for future state (tax jurisdiction) change
• Single vs Married Expense Profile
• Graphical reports
• Pension/Annuity income sources with parameters for inflation adjustment and survivorship
• Administrative tools such as the capture of all relevant parameters to a parameter file
• Developer tools including various logs and comparison tools.

JRTN is licensed via the Apache V2.0 license. The details of what you can and can’t do with this license are specified in the license specification. That said, this is a relatively permissive license; you can pretty much do whatever you want with JRTN so long as copyright information is maintained. For example, you could create a derivative work if desired.

JRTN has been a retirement hobby project. The initial motivation was to gain a better understanding of my own situation. After that it took on a certain entertainment value as I have always loved programming (and spreadsheets, for that matter). There is enough code and enough coding challenges to be “interesting.” I have moved forward to publish this for two reasons. The first is simply that it adds to the entertainment factor as the problem scope for a generally useful tool is bigger than what I personally need. Beyond that, it is rewarding to do something that is at least potentially “useful.” It is just part of the DNA.

A possible ‘just about entertainment” compromise is to look at publishing the manuscript. It would be fun to make just a little money on the activity (and provide a small write-off).