Tools

Building tools I actually use. When I can’t find a good version of something online, I build my own. This is where those tools live—some finished, some still evolving.

The retirement calculator started here before spinning off to its own site.

Consider this the workshop where you can help me kick the tires.


HelloRatio If you walk down the street, will a stranger say hello? The HelloRatio is a crowdsourced friendliness index built from real walks logged by real people—mostly me. We’re building the dataset now. Walking shoes required.

Sauna Calculator How long do you actually need to trigger heat-shock proteins? This tool uses real thermoregulation research to translate your setup—dry sauna, steam room, or hot tub—into a realistic exposure estimate.

Cold Exposure Calculator Ice bath, cold plunge, or cold shower—how long until you hit CSP, BDNF, and brown fat activation? Built on Søberg Protocol research and actual thermophysiology.

Can I Retire…Yet? Finally, a retirement calculator that isn’t full of crap. It runs 10,000 Monte Carlo simulations across 99 years of market history, models real taxes, handles RMDs, and tells you—with brutal honesty—whether you can actually retire.

Flow Finder A productivity timer based on how your brain actually works. Four research-backed modes—from 25-minute Pomodoros to 90-minute ultradian deep work sessions—plus custom controls to find your own rhythm. No gamification or badges, rejoice!

I’m Dave

Welcome to the Flynnternet, where we share An Idea, Every Monday.

We’ll travel across business, sports, pop culture, and everyday life to tell stories that explain our human operating system.

Incentives, human nature, perspective, and the small decisions that compound.

Let’s connect


Keep the Flynnternet Wild and Free

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