PFT Calculator

Estimate lung volume prediction indices (FVC, FEV1, FEV1/FVC) based on demographics.

PFT Calculator Options
Result Details
Enter parameters and click Calculate to view.
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Clinical Tool

PFT Calculator

Evaluate Pulmonary Function Test references.

100% Free & Local
STEP 01

Demographics Info

Enter the patient's biological gender, age in years, and height in centimeters.

STEP 02

Select Ethnicity

Choose the ethnic background reference group (GLI-2012 standards) to scale parameters.

STEP 03

Linear Estimations

The system runs Knudson / ERS spirometry regression equations to find ideal capacity limits.

STEP 04

Evaluate Lung Stats

Review the calculated predicted FVC, FEV1, and their ratio representing respiratory health limits.

Your Privacy Matters

All calculations run locally in your browser.

No Server Uploads

No variables or results are sent to our servers.

Auto-Cleared

Your session data is erased upon closing the tab.

Capabilities

Key Capabilities

Complete Features

Knudson Reference Norms

Integrates standard spirometry regression models to predict lung capability baselines.

FEV1/FVC Calculations

Determines key obstructive or restrictive index thresholds (FEV1 divided by FVC).

GLI Ethnic Adjustments

Applies statistical adjustments reflecting chest cavity variations between ethnic categories.

Anatomical Sex Weights

Factors in different lung capacity sizes between male and female chest builds.

Private Clinical Doses

Patient height, age, and respiratory metrics process solely client-side in the browser.

Help

Common Questions Answered

Support
Q1 What is FVC in spirometry?
Forced Vital Capacity (FVC) is the maximum total volume of air a person can forcefully exhale after taking the deepest breath possible.
Q2 What is FEV1 in spirometry?
Forced Expiratory Volume in 1 second (FEV1) measures the volume of air exhaled during the first second of the forced FVC maneuver.
Q3 What does a low FEV1/FVC ratio indicate?
A ratio below 70% (or below the Lower Limit of Normal) typically points to obstructive lung patterns, common in asthma or COPD.
Q4 Why does height play a major role in lung volume predictions?
Taller individuals naturally have larger ribcages and larger thoracic cavities, which correlates with greater baseline lung volumes.
Q5 Is this calculator a substitute for diagnostic spirometry tests?
No. This tool provides predicted reference values. It must be compared with actual patient test curves to establish diagnoses.