About Cold Plunge Calc

The goal is narrow and honest: help you pick a sensible time in the water for your temperature, experience, and goal — and then build the habit safely over weeks instead of chasing one heroic session. It is a planning and tracking tool, not a coach and not a doctor.

Everything runs in your browser. There is no account, no upload, and no "premium plan" gating the numbers. If a feature can work locally, it does.

The time ranges come from a transparent model, not a black box. We start from water temperature (the single biggest driver of risk and of how long is reasonable), then adjust for your stated experience level and goal, and finally cap everything against conservative safety limits drawn from public health guidance on cold-water immersion.

The weekly target — roughly 11 minutes of cold exposure per week — comes from Dr. Susanna Søberg's observation that regular cold-water swimmers averaged about that much, spread over two to three days. We treat it as a ceiling to ramp toward gradually, not a number to hit on day one. ^[1]

Health claims on this site are tied to identifiable, checkable sources rather than blog hearsay. In order of preference we lean on:

• Peer-reviewed research and government health bodies (e.g. studies indexed on PubMed, NIH guidance).
• Major clinical institutions writing for the public (e.g. Cleveland Clinic, Harvard Health). ^[2]
• Reputable medical-reviewed health publishers, used only to explain, never as the sole basis for a claim.

Three rules keep this site honest:

• No invented numbers. If we cannot point to a source for a figure, we describe it qualitatively instead of fabricating precision.
• Sources are linked, not just name-dropped. Every page that makes a health claim carries a references section with real outbound links you can open and read.
• We say when we don't know. Cold therapy research is young; where evidence is thin or mixed, we tell you that rather than overselling.

Cold Plunge Calc is built and maintained by an independent developer, not a clinic or supplement company. That independence is the point: nothing here is trying to sell you a $4,000 tub. It also means we are not medical professionals — which is exactly why we cite people who are, and why the disclaimer below matters.

A calculator cannot examine you. It does not know your blood pressure, your heart history, or how your body reacted to the cold last time. Use the numbers here as an informed starting point and let a qualified physician — and your own body — have the final say.