Accuracy Percentage Calculator

Accuracy is a crucial metric in fields such as data science, statistics, machine learning, research, and practical measurements. Whether you are evaluating a model, confirming test outcomes, or measuring precision, accurately calculating the accuracy percentage is vital.  

Our Accuracy Percentage Calculator enables you to compute accuracy utilizing three commonly used methods:

1. Standard Accuracy (Confusion Matrix)
2. Prevalence Method
3. Percent Error Accuracy (Observed vs True Value)

What Is Accuracy Percentage?

Accuracy Percentage measures how close your predictions, results, or measurements are to the true or expected values. It is expressed as a percentage from 0% to 100%, where:

• 100% Accuracy = perfect prediction or measurement
• 0% Accuracy = completely incorrect prediction or measurement

Standard Method (Confusion Matrix)

This method utilizes a confusion matrix, which displays the accuracy of predictions, indicating how many were correct and how many were incorrect.

Confusion Matrix Terms

1. True Positive (TP): Correctly predicted positive
2. True Negative (TN): Correctly predicted negative
3. False Positive (FP): Incorrectly predicted positive
4. False Negative (FN): Incorrectly predicted negative

Formula:

$$\text{Accuracy Percentage}=\frac{\mathrm{TP}+\mathrm{TN}}{\mathrm{TP}+\mathrm{TN}+\mathrm{FP}+\mathrm{FN}}\times 100$$

This calculates the proportion of correct predictions out of total predictions.

Prevalence Method

The prevalence method relies on the natural distribution of positives and negatives. This method is common in:

• Medical testing
• Imbalanced datasets
• Binary classification problems
• Epidemiological studies

Formula:

$$\text{Accuracy}=(\text{Sensitivity}\times \text{Prevalence})+(\text{Specificity}\times (1-\text{Prevalence}\left)\right)$$

where,

$$\text{Sensitivity}=\frac{\mathrm{TP}}{\mathrm{TP}+\mathrm{FN}}$$

$$\text{Specificity}=\frac{\mathrm{TN}}{\mathrm{FP}+\mathrm{TN}}$$

Prevalence = The number of people in the population that has the disease at a specific time.

Percent Error Method

Percent Error measures how much an observed value differs from the true or accepted value. Accuracy is derived from the inverse of this error.

Formula: 

$$\text{Percent Error}=\left(\frac{\left|\text{Observed Value}-\text{True Value}\right|}{\text{True Value}}\right)\times 100$$

The greater the error, the lower the accuracy.

$$\text{Accuracy Percentage}=100-\text{Percent Error}$$

How to Use Our Accuracy Percentage Calculator

1. Select the method you want to choose: Standard, Prevalence, or Percent Error.
2. Enter the values of TP, TN, FP, and FN under the Standard Method.

or

Enter the TP, TN, FP, FN, sensitivity, and specificity values under the Prevalence Method.

or

Enter the Observed and True values under the Percent Error Method.

3. Click “Calculate” and the calculator instantly calculates the Accuracy.