Various (Masimo, Nonin, Zacurate)

Fingertip Pulse Oximeter

Twenty-five dollars of genuinely useful hardware — with one important caveat about skin tone that most listings won't tell you.

Year one: $35; one-off
Hardware: $35; ~$25–60; clinical-grade units (Masimo, Nonin) cost more and are worth it
Subscription: None; not required
Battery: AAA batteries

A fingertip pulse oximeter estimates blood-oxygen saturation and pulse in seconds. It's the cheapest way to sanity-check a wearable's overnight oxygen readings, and it's genuinely useful during respiratory illness. Buy a clinical brand rather than the cheapest listing — accuracy between models varies far more than price does.

Is the measurement validated?

Well-established technology, but published evidence shows pulse oximeters can overestimate oxygen saturation in people with darker skin, occasionally missing genuine hypoxaemia. The FDA has issued guidance on this. Interpret borderline readings with that in mind and don't rely on a single number.

What it measures · 2

Blood oxygen (SpO₂)
Heart rate

Does it reach your record?

Manual

Most are standalone — log readings manually.

Explore your health record →

Best for

Spot-checking a wearable's oxygen data, or keeping at home for respiratory illness.

Watch out

Skin-tone bias is real and documented. Cold fingers, nail polish and movement all degrade readings.

Price checked 2026-08-09 and quoted at MSRP — hardware pricing moves. Consumer devices estimate rather than diagnose; discuss anything clinical with your doctor.

within Blood pressure & heart