Retirement planning for iPhone, iPad and Mac
Longlight runs your household's money month by month to the end of the plan, works out every year's federal and state taxes, and tests the result against 10,000 simulated market futures.
Free to download. No account needed.
The Overview for a sample household, Michael, 45, and Jennifer, 43.
What you get
Enter your paychecks, savings, home, children and goals. Longlight takes it from there, month by month to the plan's last year.
Chance of success
Longlight runs your plan through 10,000 simulated market futures and counts how many cover every expense to the end. For the futures that fall short, it shows the years the money would run out.
Taxes Pro
Year by year, Longlight fills in a federal return line by line, plus your state's, and pays each bill from the next January's cash. Brackets, deductions and thresholds are the IRS's 2026 figures.
History replay Pro
History replay starts a copy of your plan in 1871 and runs it through the markets and inflation that followed, then from 1872, and from every later year with enough history to reach your plan's end.
Lifetime cash flow
Pick any year of the plan. Income and withdrawals sit on one side, spending, debt, savings and taxes on the other, so a year's money reads at a glance.
Make scenarios of the plan, move the sliders, and compare them side by side.
Your plan re-run at every claiming age, and what each leaves at the horizon.
Room under each bracket top, Medicare cliffs included, year by year.
Which account funds which year, and when required distributions begin.
Enter the balances you actually see and read whether you're ahead or behind.
Assumptions, charts, numbers and the methodology, with the disclaimer on every page.
Why you can trust the numbers
A retirement plan is only as good as its tax rules. Longlight's come from the documents themselves, and you can check each one.
Rules and tables come from the IRS, the Social Security Administration, federal regulations and the states' own tax booklets, listed with their editions and dates.
Browse the sourcesThe tests behind each tax and benefit rule reproduce the worked examples its source document prints, and the tables are checked against the documents by hand before a release.
How Longlight works explains how each number is computed, and lists what the app leaves out.
Read how it worksPrivacy
There is no account to create and no Longlight server to send your plan to. The app has no networking code at all.
Read the privacy policyFree and Pro
The numbers are the same on both. One purchase covers iPhone, iPad and Mac.
Your whole plan, taxes included
Free to download, with no time limit.
Every page and tool
Yearly, monthly or once. The yearly plan starts with a free week for first-time subscribers. Prices are shown in the app.
Questions
No. Longlight is an educational planning tool. It shows where your own numbers and assumptions lead. Before acting on a result, check it, and consider a fee-only fiduciary advisor or a CPA.
On your devices. There is no account and no Longlight server. If you turn on iCloud sync, your plans move between your devices through your own iCloud, with the amounts in encrypted fields.
Federal brackets, deductions and thresholds are the IRS's figures for 2026, and the state tables are for tax year 2025. They are held fixed for the plan's later years and updated with the app.
The free app runs your whole plan, taxes included, and shows the Overview, Chance of success, Net worth and Lifetime cash flow. Pro opens the other pages, scenarios, check-ins and the PDF report. See everything in Pro.
iPhone, iPad, and a Mac with Apple silicon. One purchase covers all three, and iCloud sync, if you turn it on, keeps your plans in step.
A few things on purpose, such as married filing separately, stock options and state estate taxes. The full list is on How it works.
Download Longlight free for iPhone, iPad and Mac.
Coming soon