How we source this
You are about to make a decision about the next twenty years of your life using numbers off a website you have never heard of. This page exists so you can judge how much of it to trust.
Financial independence has a bad case of the confidently repeated statistic. A figure gets published somewhere respectable, gets quoted without its caveats, and by the tenth repeat it has lost the sample size, the population and the fact that a company selling annuities paid for it. Below are the rules we hold ourselves to, and the claims those rules threw out.
What every figure has to pass
A primary source, or we don't run it
Every figure has to trace back to the study, the survey or the government dataset it came from — not to an article about it. If we follow a claim back and the chain ends in a blog post, a press release or a page with no method, the claim doesn't go on the site, however well it fits what we're saying.
We say who the number describes
A figure is only meaningful attached to a population. A withdrawal rate reported by high-earning US tech workers on a self-selected survey is a different fact from one measured across all retirees, and we won't print the first while implying the second. Where a study's population doesn't match the reader's, we say so.
Sample size and method sit next to the figure
Not in a footnote you have to hunt for. If a number comes from 297 self-reported responses, that appears beside the number, because it changes how much weight it deserves.
We name who paid for the research
A lot of the most quotable retirement research is published by firms that sell retirement products. That doesn't make it wrong, but it does mean nobody had an incentive to publish the gloomier finding. Where we cite industry-funded work, the funding is stated in the same breath as the result.
Nothing is dressed up as more settled than it is
Almost nobody has studied people who stop working in their thirties and forties. When the honest answer is that the evidence is thin or doesn't exist, we say that rather than borrowing a finding from a neighbouring population and hoping you don't check.
Five claims we checked and refused to use
All five are in wide circulation, and every one of them would have made a better headline than the truth. Each is listed here with what we found when we followed it back, so you can check our working.
“97% of retirees with a strong sense of purpose are happy, against 76% without.”
We found it on a large asset manager's own website, laid out like research. The footnote credits a personal finance blog. There is no study behind it, no sample size and no method. The chain ends in nothing.
“Retire at 55, die at 65.”
Usually attributed to an internal Boeing study, often with a chart. No such study has ever been produced, and Boeing denies it exists. The good longevity research points the other way.
“A sense of purpose cuts mortality risk by 23%, across 137,142 people.”
The real meta-analysis (Cohen, Bavishi and Rozanski, 2016) reports a risk ratio of 0.83 across 136,265 people. The widely-shared version overstates both the effect and the sample. The finding is real; the number in circulation is not.
“Somewhere around year two of retirement, the loneliness arrives.”
Traces back to a page written for search engines with no study behind it, and it is contradicted by the actual longitudinal work on retirement adjustment.
“Early retirement raises the risk of mental illness.”
Rests on a 2005 study whose early-retiree group was overwhelmingly people who had left work because they were ill — 71% of the men and 66% of the women reported a long-standing illness. It cannot separate the cause from the effect, and that population is close to the opposite of someone retiring early by choice.
How the calculators work
The same standard applies to the maths. Nothing is hidden inside the tool, and anything that would change your answer is on the screen and editable.
Everything is in today's money
We ask for a return above inflation and report every figure in today's terms. Calculators that grow a nominal balance towards a target priced in today's money flatter the result badly over twenty-five years. This is the single biggest reason two tools give you two answers.
The formulas, in full
Your target is annual spending divided by your withdrawal rate. The amount you need invested today is that target discounted back at your real return over the years remaining. Coasting means contributions stop entirely — the coasting line assumes you never add another dollar.
Tax is not modelled
We take your spending figure at face value. If the income you retire on is taxable, your real target is higher than this tool or any of the others will tell you. We would rather say that plainly than bury an assumption about your account mix.
A smooth average is not a promise
Like every tool of this kind, ours applies one steady return each year. Real markets arrive in a sequence, and two people with the same average can land in very different places depending on which years the bad ones fall in. Treat the output as a planning estimate, never as a floor.
Why there is no author name on any of this
Because a name at the top of a page is not evidence, and we would rather you checked the sources than took anyone's word for it.
Personal finance is full of credentials used as a substitute for citation. The alternative we have picked is that every number is traceable and every assumption is visible, so nothing on the site depends on you trusting the person who wrote it. If a figure here is wrong, you should be able to find that out from the source we linked rather than from us.
When we get it wrong
Errors get corrected on the page itself, not quietly overwritten. A corrected page carries a note saying what the figure used to say, what it says now and what changed our mind. Figures that depend on live conditions — health insurance costs, tax thresholds, anything legislative — carry the date they were last checked, so you can see for yourself when a number has gone stale.
Every figure on the site is US-specific unless it says otherwise, and all of it was last reviewed in July 2026.
What this site is not
It is not advice. firelytics is not a registered investment adviser, nothing here is personalised to your circumstances, and no calculator knows anything about your tax position, your health or your job security. It is arithmetic with its assumptions showing. What you do with the answer is a decision worth taking to someone qualified who knows your situation.
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