The Big Beautiful Bill Changed Your Retirement Math. Here's What's Different in 2026.

The One Big Beautiful Bill Act — signed into law on July 4, 2025 — is the most significant overhaul of the US tax code since 2017. Most of its retirement-specific provisions took effect January 1, 2026. If you haven't revisited your retirement plan since it passed, you may be leaving meaningful money on the table.

Three changes matter most for personal retirement planning. Two are available right now. One launches in July 2026.

The Catch-Up Change That Most People Are Missing

The enhanced catch-up for ages 60–63 is the biggest retirement math change in the OBBBA for most workers approaching retirement. The extra $3,750 per year above the standard $31,000 limit for over-50s may not sound transformative — but its compounding effect over five years at typical pre-retirement returns is meaningful.

Consider a 60-year-old planning to retire at 65. At a 6% nominal return, contributing the full $34,750 rather than $31,000 over five years adds approximately $21,000 to the final portfolio value, according to standard compound growth calculations. That extra $21,000 — representing roughly four additional months of retirement drawdown at a $5,000/month withdrawal rate — comes purely from taking advantage of a contribution limit that didn't exist before 2026.

The Retirement Calculator models this precisely. Try this: enter your current age (60–63), current savings balance, annual return assumption, and compare the retirement balance at 65 using $31,000 versus $34,750 annual contributions. The gap between those two scenarios is the dollar value of the new limit. Don't be reactive to tax law changes — model them rationally and act on the numbers. The OBBBA changed the inputs. Go update your plan.

What the Senior Bonus Deduction Actually Saves

The $6,000 senior bonus deduction is available to anyone 65 or older who isn't already phased out by income. For a single filer in the 22% tax bracket earning $60,000, a $6,000 deduction saves approximately $1,320 in federal tax per year. For a married couple in the 24% bracket earning $120,000, a combined $12,000 deduction saves $2,880.

That tax saving runs through 2028 — four tax years. A single filer saving $1,320 annually and redirecting it to an investment account earning 6% accumulates approximately $5,800 over that period. Not enormous. But it's real money that wasn't available before the OBBBA, and it's completely free to claim without itemising.

The Compound Interest Calculator models what that annual tax saving compounds to if invested rather than spent. Enter the annual tax saving as a recurring monthly contribution (divide by 12), set the return rate, and run it forward over your expected retirement window. Every dollar in tax savings that gets invested rather than spent is worth more than a dollar at market returns over time.

What the Bill Didn't Change (And What Could Still Change)

The OBBBA made no changes to rules governing Roth IRAs, Required Minimum Distributions, or backdoor Roth strategies — a significant point for higher-income savers who had prepared for potential restrictions. Those provisions were discussed in committee but didn't survive. The current rules remain in place.

Social Security remains taxable despite early speculation to the contrary. However, the new senior bonus deduction provides an indirect offset for many retirees. And because the OBBBA permanently extended the lower tax brackets and larger standard deduction from the 2017 TCJA, Roth conversion planning can now be modelled with greater certainty — the brackets aren't reverting to pre-2017 levels as they otherwise would have done on January 1, 2026.

The bill also worsened Social Security's projected insolvency timeline slightly, according to JP Morgan Asset Management, by reducing payroll tax receipts through tip and overtime exemptions. That reinforces the importance of self-funded retirement accumulation — don't model your retirement assuming full Social Security income. The Retirement Calculator lets you set the Social Security income assumption directly; try both full benefit and a 20% haircut and see the difference in required portfolio size.