This peak flow calculator helps you estimate the predicted maximum speed of expiration according to age, gender and height and check if your measured value is around it. You can discover more on this subject and discover an example calculation below the form.

Measured peak flow:

How does this peak flow calculator work?

This is a quick health tool that determines the estimated or predicted peak flow based on your data.

You need to select your gender and input your age and height. The former can be put in either metric (cm) or English (inches) measurement.

If you already have a peak flow determination you can input that as well to get an extra info in the result.

Based on peak flow formulas, the calculator computes the predicted value in your case and extracts the percentage the measured figure is out of the prediction. You can use the form as many times as you like varying the information or personal data.

Example calculation:

■ Let’s take for instance the case of a female aged 32 with a height of 175cm. Her estimated peak flow value would be 467.4 L/min.

■ Or in the case of a male aged 27 with a height of 186 cm. His predicted peak flow value would be 639.948 L/min. But if he already has a measured peak flow of 568 L/min, the percentage is 88.76.


1) Nunn AJ, Gregg I. (1989) New regression equations for predicting peak expiratory flow in adults. BMJ; 298(6680):1068-70.

2) Knudson RJ, Lebowitz MD, Holberg CJ, Burrows B. (1983) Changes in the normal maximal expiratory flow-volume curve with growth and aging. Am Rev Respir Dis; 127(6):725-34

19 Mar, 2015