Vital Capacity Calculator

Estimate predicted vital capacity from age, sex, and height, then compare it against a measured spirometry reading to get percent of predicted.

Quick Facts

Formula
Baldwin-Cournand-Richards (1948)
Male: (27.63 - 0.112 x age) x height. Female: (21.78 - 0.101 x age) x height, in mL/cm.
Typical adult range
About 3 to 5 liters
Varies widely with body size, sex, age, and fitness.

Your Results

Calculated
Predicted vital capacity
-
From age, sex, and height
Measured vital capacity
-
As entered from spirometry
Percent of predicted
-
Measured / predicted x 100
Interpretation
-
General severity band

Ready

Enter sex, age, height, and your measured vital capacity, then calculate.

About vital capacity

Vital capacity (VC) is the maximum volume of air a person can exhale after taking the deepest possible breath in. It is one of the oldest and most widely measured lung volumes, recorded with a spirometer as part of standard pulmonary function testing. Because vital capacity scales with body size, sex, and age, a single measured value only becomes meaningful when it is compared against a predicted value for someone with the same profile.

The Baldwin-Cournand-Richards formula

This calculator uses the regression equations published by Baldwin, Cournand, and Richards in 1948, a standard textbook method for estimating predicted vital capacity from age, sex, and height:

  • Male: Predicted VC (mL) = (27.63 - 0.112 x age in years) x height in cm
  • Female: Predicted VC (mL) = (21.78 - 0.101 x age in years) x height in cm

Both equations produce a coefficient in milliliters per centimeter of height that shrinks slightly with age, then multiply that coefficient by height to get the predicted volume. Percent of predicted is then the measured vital capacity divided by this predicted value, multiplied by 100.

How to get accurate results

  • Use a standing height measured without shoes; height error translates directly into predicted-volume error.
  • Enter age in whole years and make sure the measured vital capacity comes from a proper maximal-effort spirometry maneuver, not a casual breath.
  • Keep units consistent: this calculator expects height in centimeters and volumes in milliliters.

Putting the result in context

Percent of predicted lets you compare a measured value against what is typical for someone of the same age, sex, and height. As a general guide, values at or above 80% of predicted are usually considered within the normal range, while lower percentages suggest progressively greater reduction. These bands describe population patterns, not a diagnosis for any one person.

When to consult a professional

This calculator performs the standard predicted-vital-capacity arithmetic for education and self-tracking. It does not diagnose a lung condition. If a measured vital capacity is low, trending downward, or accompanied by symptoms such as breathlessness, consult a licensed healthcare provider who can interpret the full spirometry report alongside your history and other test results.

Frequently Asked Questions

What formula does this calculator use for predicted vital capacity?
It uses the Baldwin, Cournand and Richards (1948) regression equations, one of the standard textbook formulas for predicted vital capacity. For males, predicted VC in milliliters equals (27.63 minus 0.112 times age in years) multiplied by height in centimeters. For females, it equals (21.78 minus 0.101 times age in years) multiplied by height in centimeters.
What is vital capacity and how is percent of predicted calculated?
Vital capacity is the maximum volume of air a person can exhale after a full inhalation, measured by spirometry. Percent of predicted is your measured vital capacity divided by the age-, sex-, and height-based predicted value, multiplied by 100. It lets you compare a spirometry reading against what is typical for someone with the same profile.
What do the percent-of-predicted bands mean?
As a general guide, 80 percent of predicted or higher is usually considered within the normal range, 65 to 79 percent suggests mild reduction, 50 to 64 percent suggests moderate reduction, and below 50 percent suggests severe reduction. These bands are a simplified guide, not a diagnosis, and a clinician should interpret any spirometry result alongside the full test and clinical picture.

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