Free health calculators
Twelve free calculators for your resting pulse, HRV, sleep and body
Twelve calculators that turn a resting pulse, a bedtime or a tape measure into something you can act on. Every one runs in your browser, shows its working, and names the study behind it.
- 12tools
- 0sign-ups
- 21studies cited
Method
The research behind the tools
Every calculator is built on peer-reviewed studies and published reference values. These are the key sources behind the formulas.
- Sources listed on every tool
- No data leaves your browser
- Estimates, never a diagnosis
Cardiovascular
- Zhang D et al. (2016). Resting heart rate and mortality. CMAJ, 188(3). PMC
- Shaffer F, Ginsberg JP (2017). HRV metrics and norms. Front Public Health, 5:258. PMC
- Spodick DH (1992). Normal sinus heart rate. Am Heart J, 124(4).
- Koenig J, Thayer JF (2016). Sex differences in HRV. Neurosci Biobehav Rev, 64.
- Aubert AE et al. (2003). HRV in athletes. Sports Med, 33(12).
- Nes BM et al. (2011). Non-exercise VO2peak, HUNT. Med Sci Sports Exerc, 43(11). PubMed
Sleep & Recovery
- Hirshkowitz M et al. (2015). NSF sleep duration recommendations. Sleep Health, 1(1).
- Feinberg I, Floyd TC (1979). Sleep cycle trends. Psychophysiology, 16(3).
- Mah CD et al. (2011). Sleep extension and athletic performance. Sleep, 34(7).
- Halson SL (2014). Monitoring training load. Sports Med, 44(S2).
- Saw AE et al. (2016). Self-report monitoring in athletes. Br J Sports Med, 50.
Body Composition
- Deurenberg P et al. (1991). BMI and body fatness. Br J Nutr, 65. PubMed
- Hodgdon JA, Beckett MB (1984). US Navy body fat formula. Naval Health Research Center.
- Kouri EM et al. (1995). Fat-free mass index. Clin J Sport Med, 5(4).
- ACSM (2021). Guidelines for Exercise Testing and Prescription, 11th ed.
Lifestyle & Training
- Arem H et al. (2015). Physical activity and mortality. JAMA Intern Med, 175(6).
- Ekelund U et al. (2019). Sedentary time and mortality. BMJ, 366.
- Wang X et al. (2014). Fruit/vegetable consumption and mortality. BMJ, 349.
- Wood AM et al. (2018). Alcohol risk thresholds. Lancet, 391.
- Meeusen R et al. (2013). Overtraining syndrome consensus. Med Sci Sports Exerc, 45(1). PubMed
- Kellmann M, Kallus KW (2001). RESTQ-Sport. Human Kinetics.
The app
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