ChatPPG.

Free physiology tool

SpO₂ at altitude checker

Normal oxygen saturation falls as you go higher. In 6,289 healthy, acclimatised residents of the Andes, the median SpO₂ was 99% at 154 m, 96% at 2,500 m, 92% at 3,600 m, 87% at 4,100–4,500 m and 81% at 5,100 m (Rojas-Camayo et al., 2018). Enter an altitude to see the published median and interquartile range for the nearest study sites, and optionally compare your own reading.

Updated . Free, no sign-up. Calculations run in your browser and your data is never uploaded. Educational reference, not medical advice.

Your altitude

Everything is calculated in your browser. Nothing you type is sent anywhere.

Expected SpO₂ in healthy, acclimatised residents

Median
92%
Middle 50% (IQR)
90%–93%
Altitude
3,600 m
Study sitenMedianIQR
3,600 m36192%90–93%

Source: Rojas-Camayo et al., Thorax 2018. 6,289 healthy people aged 1–80 who had lived at least 2 months at each altitude, measured with a medical-grade pulse oximeter (Nellcor N-560). These are all-ages values. Age-specific tables are in the paper's supplement.

SpO₂ by altitude: all study sites

8085909510001,0002,0003,0004,0005,000Altitude (m)SpO₂ (%)

The line shows the median and the band the interquartile range at each of the 15 study sites (Rojas-Camayo et al., 2018). The open circle at 3,250 m marks a site with no printed median. The dashed line is your altitude.

Show the table
AltitudenMedianIQR
154 m70999%98–99%
562 m40599%98–99%
1,400 m31598%97–99%
2,000 m20997%96–98%
2,335 m52297%96–99%
2,500 m41696%95–97%
2,880 m40495%94–96%
3,250 m422not printed92–95%
3,600 m36192%90–93%
3,950 m35090%88–91%
4,100 m64487%85–89%
4,338 m45787%85–89%
4,500 m52587%85–89%
4,715 m25185%83–88%
5,100 m29981%78–84%

If you're using a smartwatch or ring

The reference values above come from a medical-grade pulse oximeter. Wrist and finger wearables add their own error, so a single wearable reading can sit a few points away from what a clinical oximeter would show. In one study of a smartwatch at four sites from 500 to 4,014 m, SpO₂ error stayed within the ISO 80601-2-61 benchmark (RMSE 0.19–0.81%). Error variability was much higher in lowlanders who had just arrived (Xu et al., 2026). That's one device and one study. See the published results for other devices in wearable SpO₂ accuracy and the PPG research hub.

Educational reference only, not medical advice. This tool can't diagnose altitude sickness or any other condition. How you feel matters more than any single number. If you feel unwell at altitude, get medical help whatever your SpO₂ reads.

Cite this analysis

Cite the methods papers for the statistics you report, and the tool if it helped. ChatPPG. SpO2 at Altitude Checker (version 1.0). 2026. https://chatppg.com/tools/spo2-at-altitude. Accessed 2026-10-18.

Preview BibTeX
@software{chatppg_spo2_at_altitude_2026,
  author = {{ChatPPG}},
  title = {{SpO2 at Altitude Checker}},
  year = {2026},
  version = {1.0},
  publisher = {ChatPPG},
  url = {https://chatppg.com/tools/spo2-at-altitude},
  urldate = {2026-10-18}
}

@article{rojas2018,
  author = {Rojas-Camayo, Jose and Mejia, Christian Richard and Callacondo, David and Dawson, Jennifer A. and Posso, Margarita and Galvan, Cesar Alberto and Davila-Arango, Nadia and Bravo, Erick Anibal and Loescher, Viky Yanina and Padilla-Deza, Magaly Milagros and Rojas-Valero, Nora and Velasquez-Chavez, Gary and Clemente, Jose and Alva-Lozada, Guisela and Quispe-Mauricio, Angel and Bardalez, Silvana and Subhi, Rami},
  title = {{Reference values for oxygen saturation from sea level to the highest human habitation in the Andes in acclimatised persons}},
  journal = {Thorax},
  year = {2018},
  volume = {73},
  number = {8},
  pages = {776--778},
  doi = {10.1136/thoraxjnl-2017-210598}
}

@article{crocker2020,
  author = {Crocker, Mary E. and Hossen, Shakir and Goodman, Dina and Simkovich, Suzanne M. and Kirby, Miles and Thompson, Lisa M. and Rosa, Ghislaine and Garg, Sarada S. and Thangavel, Gurusamy and McCollum, Eric D. and Peel, Jennifer and Clasen, Thomas and Checkley, William},
  title = {{Effects of high altitude on respiratory rate and oxygen saturation reference values in healthy infants and children younger than 2 years in four countries: a cross-sectional study}},
  journal = {The Lancet Global Health},
  year = {2020},
  volume = {8},
  number = {3},
  pages = {e362--e373},
  doi = {10.1016/S2214-109X(19)30543-1}
}

@article{xu2026,
  author = {Xu, Runhao and Guo, Jiajun and Li, Weihao and Xie, Zimo and Zhai, Yujia and Jiang, Siyuan and Li, Yue and Xia, Kailun and Chen, Yucheng},
  title = {{Accuracy of wearable smartwatch for measuring blood pressure and oxygen saturation across a wide altitudinal gradient: a comparative study in Migrant and Resident populations}},
  journal = {Frontiers in Physiology},
  year = {2026},
  volume = {17},
  pages = {1746894},
  doi = {10.3389/fphys.2026.1746894}
}

Where the numbers come from

The main reference is Rojas-Camayo et al. (Thorax, 2018). The team measured SpO₂ in 6,289 healthy people aged 1–80 years at 15 sites in Peru, from 154 m to 5,100 m (described by the authors as the highest permanent human habitation). Everyone had lived at that altitude for at least two months. Readings were taken with a medical-grade pulse oximeter (Nellcor N-560). The tool shows the all-ages median and interquartile range printed in the paper. When your altitude falls between two sites, it shows both sites and draws a straight line between them. It doesn't use a fitted equation.

The paper's age-specific tables sit in a supplement, so this tool doesn't reproduce them. The authors note their sample was Andean natives and Hispanics, and advise care when applying the values to other populations.

Babies and toddlers

For children under 2, the tool switches to Crocker et al. (Lancet Global Health, 2020). That study measured 1,570 healthy children aged 0–23 months in India (1–919 m), Guatemala (1,036–2,017 m), Rwanda (1,449–1,644 m) and Peru (3,827–4,348 m). Mean SpO₂ was 98.3%, 97.3%, 96.2% and 89.7% respectively. Any reading in a young child should be discussed with a clinician.

Recent arrivals are different

These references describe people who are acclimatised. In the first days at altitude your saturation can differ from a long-term resident's, and readings vary more from one person to the next. If you're travelling, use the ranges as context rather than a target. Read more about how PPG sensors behave at altitude in PPG and altitude adaptation.

Wearables at altitude

Most people check SpO₂ at altitude with a watch or ring rather than a medical oximeter. One study of a smartwatch at four sites from 500 to 4,014 m found SpO₂ RMSE of 0.19–0.81%, within the ISO 80601-2-61 benchmark. Error variability was much higher in lowlanders who had just arrived (Xu et al., 2026). That's a single device, so check published results for yours in wearable SpO₂ accuracy and the wearable SpO₂ comparison. Skin tone and perfusion also affect optical SpO₂; see the SpO₂ and skin-tone datasets in the research hub.

Frequently asked questions

What is a normal SpO2 at high altitude?

It depends on how high. In healthy acclimatised residents (Rojas-Camayo et al., 2018), the median was 97% at 2,000 m, 95% at 2,880 m, 92% at 3,600 m, 90% at 3,950 m, 87% at 4,100–4,500 m and 81% at 5,100 m. The middle 50% of people sat within about 1–3 points of the median.

What is a normal oxygen level at 3,000 m (about 10,000 ft)?

The nearest study sites are 2,880 m (median 95%, IQR 94–96%) and 3,250 m (IQR 92–95%; the paper doesn't print a median for that site). Healthy acclimatised residents at around 3,000 m typically read in the low-to-mid 90s.

Does age change SpO2 at altitude?

Altitude matters at every age. Rojas-Camayo et al. report that higher altitude significantly lowered SpO₂ in all age groups, with the steepest fall above 2,500 m. The age-specific percentiles are in the paper's supplement, so this tool shows all-ages values for people aged 1–80, plus infant data from Crocker et al. (2020) for under-2s.

Is my smartwatch accurate at altitude?

It varies by device. One smartwatch stayed within the ISO accuracy benchmark from 500 to 4,014 m, but its error varied more in people who had just arrived (Xu et al., 2026). See wearable SpO₂ accuracy for published results by device.

Can this tool tell me if I have altitude sickness?

No. It's an educational reference. Altitude illness is diagnosed from symptoms and clinical assessment, not from a single SpO₂ number. If you feel unwell at altitude, seek medical help.

Is my reading uploaded?

No. Everything is calculated in your browser, and nothing you type is sent to ChatPPG or anyone else.

References

  1. Rojas-Camayo J, Mejia CR, Callacondo D, et al.. Reference values for oxygen saturation from sea level to the highest human habitation in the Andes in acclimatised persons. Thorax. 2018;73(8):776-778. doi:10.1136/thoraxjnl-2017-210598
  2. Crocker ME, Hossen S, Goodman D, et al.. Effects of high altitude on respiratory rate and oxygen saturation reference values in healthy infants and children younger than 2 years in four countries: a cross-sectional study. The Lancet Global Health. 2020;8(3):e362-e373. doi:10.1016/S2214-109X(19)30543-1
  3. Xu R, Guo J, Li W, et al.. Accuracy of wearable smartwatch for measuring blood pressure and oxygen saturation across a wide altitudinal gradient: a comparative study in Migrant and Resident populations. Frontiers in Physiology. 2026;17:1746894. doi:10.3389/fphys.2026.1746894

Related

More free tools

Wearable validation toolkitBland–Altman calculator and plotICC calculatorCohen's kappa calculatorBland–Altman sample size calculatorAll tools