Open Social Security

A Standalone Claiming Strategy Calculator Built for Accuracy

Open Social Security is a free, open-source calculator designed to solve one specific problem: figuring out the best age to claim Social Security benefits. The tool was created by Michael Piper, a CPA in St. Louis and author of financial books, with major contributions from Brian Courts. Rather than making a broad guess, the calculator runs the math for every possible claiming age and tells you which strategy is expected to provide the most total spendable dollars over your lifetime. It runs in your browser on any device and saves your inputs via URL, so you can close it and come back later with your answers still there.

The calculator is not a black box. The site lays out the math it uses: it takes your birth date, marital status (single, married, divorced, or widow/widower), and primary insurance amount (the PIA, your monthly benefit at full retirement age), then calculates the probability-weighted, discounted value of claiming at each age from 62 to 70. For married couples, it weighs spousal benefits and survivor benefits separately for each spouse and considers every combination of claiming ages between the two of you. The calculation multiplies each year's benefit by your probability of being alive that year, then discounts it back to present value to account for inflation and the time value of money. The output is a specific recommendation: the claiming age with the highest present value, weighted across all possible lifespans, along with that present value figure itself. If you are younger than full retirement age when you use it, the calculator automatically removes claiming strategies you can no longer choose. The tool considers not just single filing but also the interdependent filing choices spouses can make, which can dramatically change the optimal strategy for couples.

How to Gather Your Inputs and Use the Tool

The hardest part of using this calculator is figuring out your primary insurance amount before you enter it. The site gives three options: if you are younger than full retirement age, check your Social Security statement online (the tool points you to SSA.tools for the calculation); if you are older, call the SSA directly to ask them to calculate your PIA. The PIA itself changes over time due to new earnings, wage indexing, and cost of living adjustments, so the site warns that your calculation today will drift with your future wages and inflation. Once you have your PIA, the form takes only minutes. Fill in your marital status, gender, birth date, and PIA. If you are married, add your spouse's information (age, income, PIA, life expectancy, and Social Security estimate). The calculator runs immediately and shows you the probability-weighted outcome for each claiming age, a graph color-coded by strategy quality, and your recommended age in a summary box at the top. There is nothing to connect, no account to sign up for, and no financial data about you to send anywhere.

Strategy Ranking and Long-Term Projections

The core strength of Open Social Security is its transparency about what it is actually calculating. The calculator uses the Social Security Administration's period life table by default, which assumes median life expectancy (roughly age 82 for a male age 62, roughly age 85 for a female). But you can choose from several other tables published by the Society of Actuaries to reflect your own health: a super-preferred table for people in much better than average health (median age 87.5 for males, 90 for females), a preferred table for better-than-average health (median age 86.5 for males, 89 for females), a smoker preferred table for tobacco users in better than average health (median age 81.5 for males, 84 for females), and a smoker residual table for other tobacco users (median age 81 for males, 83 for females). This is crucial: the optimal claiming age can shift several years depending on your longevity assumptions, so the ability to choose the right mortality table for your situation matters. Everything is done in inflation-adjusted dollars, so you do not have to manually calculate the effect of inflation on your money over time. The tool is clear about its limits: it does not consider longevity risk (delaying benefits reduces the risk you will outlive your money even if it does not maximize expected spending), tax planning considerations, or other personal reasons why you might want to file earlier or later than the calculator suggests.

Cost, Access, and What the Site Does Not Settle

Open Social Security is completely free, with no payment tiers and no trial period ending. The code is open-source under the MIT license, published on GitHub. There is nothing to download or install; the calculator runs in your browser. No account is required, and the site does not ask for your email address or any identifying information. When you save your inputs as a URL, you are storing them locally in your browser's clipboard, not uploading them to any server. The site does not publish prices because there are none. What the site does not settle is whether the calculator's recommendation is actually right for you. The disclaimer on the about page warns that you should not treat this as your only analysis: there are factors (longevity, taxes, other sources of income, your own preferences) that the calculator does not consider and that might change your best claiming age. The site encourages readers to consult other resources and suggests Piper's own book, Social Security Made Simple, for deeper context.

Who This Calculator Suits and Why

Open Social Security is a good fit if you want to understand the pure financial math of when to claim and you are comfortable doing the manual work to find your primary insurance amount beforehand. It is especially useful for married couples weighing the spousal and survivor benefits that married claiming rules create, since the site models the interdependent strategies both spouses can employ and how one spouse's death affects the other's lifetime benefit. Because it is free and requires no account, it is a low-risk way to explore your options without sharing personal information with a financial company. The calculator's focus on maximizing expected lifetime spending appeals to people who want a numbers-based decision rather than a rule of thumb. The open-source code (published under the MIT license on GitHub) means that programmers and people who care about transparency can review exactly how the math works and trust the results. The calculator is not a substitute for personalized advice, particularly if your situation includes multiple income sources, inheritance, a pension, or other significant complications beyond the scenarios the tool models. It is also not a tool for managing money day-to-day; it is purely a Social Security claiming calculator with no connection to checking accounts, savings, or investments. If you need help with the broader retirement decision (how much you need to save, how to invest, what to spend), this tool does not do that.