About compoundcoast

What this site is

compoundcoast is an independent set of calculators for the three stages of a long-term plan — accumulating, reaching financial independence, and drawing down. Where most tools quote one confident figure, these report a range — measured percentiles from historical windows, or a labeled low/base/high scenario band for forward projections — apply expense ratios and the current-year tax engine before the headline, and cite the source and as-of date behind every input.

Where it came from

I built these for my own portfolio. I manage my own money and kept wanting the same handful of numbers — what a withdrawal rate survives, what a conversion ladder costs, what fees take out over thirty years — so I wrote the tools to answer them, then kept writing them. A static site costs the same whether one person opens it or a thousand, so they are up for anyone who wants the same answers.

That origin is also why the site asks nothing of you. There is no signup, no email capture, and no saved profile, because there was never anything to convert a visitor into — the first user was me. What that does not settle is how the site pays for itself, which is the next section.

How it is funded

The site carries no advertising today, and display advertising is the only revenue model being pursued for it. That matters mainly for what it rules out: there are no lead-capture forms, no email lists sold, no affiliate steering toward a product, and no data resold to third parties. Whenever advertising does arrive it will be disclosed on the privacy page before the first ad loads, and it will not touch the numbers a calculator produces.

Because the only funding pursued is advertising rather than referrals, there is no incentive to nudge you toward any brokerage, fund, or insurer. The calculators are deliberately neutral: they estimate, they do not steer.

The honesty model

Three commitments run through every tool, and they are enforced in the build, not just promised:

• Ranges over points. A single number hides the downside that matters most for a lump-sum or retirement decision.
• Sources on every figure. Each data field carries a source and an as-of date; year-dependent numbers expire and break the build when stale.
• Net of fees and tax. A gross return is never presented as spendable. The fee and tax layers are applied and shown.

The full detail lives on the methodology page — the reason the site exists.

Who runs it

I write and maintain all of it — Chris Park, a machine-learning engineer and a long-term index investor. There is no staff and no financial credential here, which is why correctness is not asked to rest on a byline: every calculator prints its formula on the page and ships with a regression test against a published standard. The full standard is on the methodology page.