01
Relevant 2026 US tax rules
Federal brackets plus state and local variations, with standard deductions and RMD schedules. Every rate carries a source citation.
Retirement Calculator 2026
How long will your retirement savings last?
See your expected finances year by year, and how the outcome shifts with different returns, spending, and retirement ages. Every rate and assumption is visible.
$9 · One-time purchase
1 / 8 What you get
Retirement Calculator 2026
02
1,000 possible market paths
We run 1,000 different market scenarios so you can see how robust your plan is if returns turn out better or worse than expected. (The technique is called Monte Carlo, see the method section for details.)
03
All US retirement sources
Social Security, 401(k), Traditional IRA, Roth IRA, HSA. Modeled against documented US rules with visible sources.
Detail
How the tool is built
Overview
All inputs, KPIs, and charts on one screen
A single tab collects it all: your numbers, the calculation result, and the charts you would show your spouse to explain the math.
Tax
2026 US tax calculation with source per rate
Federal brackets, state income tax, Social Security taxation, IRMAA thresholds. Each figure links to its source and the last update date.
Robustness
1,000 possible market paths with probabilities
Instead of a single average, you see 1,000 different paths. The chart shows the spread, the median, and the probability the money lasts.
Detail
Year-by-year view from now to age 95
Each year is one line: Social Security, savings, tax, spending, net worth. No summarizing, no hidden columns.
Trust and method
Understand the assumptions, not just the answer
This model tests the plan across 1,000 simulated market paths and shows the range between unfavorable, central, and favorable outcomes.
Built with financial expertise
Created by Christian Elkrog, an economist and tech founder with more than a decade of experience and a successful company exit.
Not a black box
Inputs, assumptions, formulas, sources, and limitations are visible so you can understand each result.
Your figures stay with you
No account connection or hidden data collection. Slowshore never receives the information you enter.
Sources
Sources and assumptions
Show sources and assumptions
IRS, Social Security Administration, MSCI World, Bureau of Labor Statistics. Source URLs are visible in the spreadsheet, with the date of the last update.
Pricing
Start with this workbook or choose the full bundle
Start with this workbook for $9, or get all 8 for $59. One-time purchase with no subscription.
Excel
A single tool
$9 per tool
- Excel + Google Sheets
- Example, blank version, and start guide
- No subscription – keep the file
- Corrections to 2026 edition included
- One-time purchase
- 14-day money-back guarantee
Bundle
All 8 workbooks
$59 one-time
- All 8 Excel workbooks
- 8 complete packages with example, blank version, and guide
- No subscription – keep the files
- Corrections to 2026 edition included
- One-time purchase
- 14-day money-back guarantee
Looking for the browser version? Join the waitlist.
FAQ
Frequently asked questions
Do I have to write formulas?
No, you fill in marked cells and everything calculates automatically.
What information do I need to have ready?
See the full list on the product page before buying. The basics: age, retirement account balances, expected spending.
Does it work on Mac and Windows?
Yes, plus Google Sheets. We send both versions after purchase.
Where is my data stored?
The Excel version stays on your own computer. We never see your numbers.
Is this financial advice?
No. It is a planning tool. Always consult a licensed advisor before major decisions.
Refunds?
14-day money-back guarantee, no questions asked.