# Centor Score Calculator (Modified McIsaac, Strep Throat)

URL: https://speedycalculator.com/calculators/health/centor/
Last updated: 2026-10-30

> The Centor score calculator estimates the probability of streptococcal pharyngitis (strep throat) from fever, tonsillar exudate, swollen neck glands, absence of cough and age (McIsaac modification), and suggests whether to test or treat.

## Inputs

- Temperature above 38 °C (100.4 °F)
- Tonsillar swelling or exudate
- Tender, swollen anterior cervical lymph nodes
- Absence of cough
- Age

## Results

- Modified Centor score
- Probability of strep and action

## Formula

```
Score = sum of the points for each item
```

## Explanation

The modified Centor (McIsaac) score helps avoid unnecessary antibiotics for sore throats, most of which are viral. Scores of 0–1 need no testing; 2–3 call for a rapid strep test or culture; 4 or more may justify testing and treatment.

### How to use the Centor Score Calculator

- **Temperature above 38 °C (100.4 °F)**
- **Tonsillar swelling or exudate**
- **Tender, swollen anterior cervical lymph nodes**
- **Absence of cough**
- **Age**

Results update as you type, and every field accepts the units shown in its menu.

### How it works

Each answer carries the points shown in the published score. The calculator adds them up and maps the total to the published interpretation.

### Scoring table

ItemAnswers and pointsTemperature above 38 °C (100.4 °F)No = 0; Yes = 1Tonsillar swelling or exudateNo = 0; Yes = 1Tender, swollen anterior cervical lymph nodesNo = 0; Yes = 1Absence of coughNo = 0; Yes = 1Age3–14 years = 1; 15–44 years = 0; 45 years or older = -1

### Inputs explained

FieldWhat to enterTemperature above 38 °C (100.4 °F)Choose one: No, YesTonsillar swelling or exudateChoose one: No, YesTender, swollen anterior cervical lymph nodesChoose one: No, YesAbsence of coughChoose one: No, YesAgeChoose one: 3–14 years, 15–44 years, 45 years or older
*Health note: this calculator is for education and screening only and is not a diagnosis or treatment advice. Discuss your results with a qualified clinician.*

## Worked example

Inputs — Temperature above 38 °C (100.4 °F): Yes; Tonsillar swelling or exudate: Yes; Tender, swollen anterior cervical lymph nodes: No; Absence of cough: Yes; Age: 15–44 years.

Results — **Modified Centor score = 3**; Probability of strep and action = 28–35% – rapid strep test.

## Key terms

- **GAS**: Group A Streptococcus.

## FAQ

**What score needs a strep test?**
2 or more, in most guidelines.

**Why not give antibiotics to everyone?**
Most sore throats are viral; unnecessary antibiotics cause side effects and resistance.

**What is FeverPAIN?**
A UK alternative score using fever, purulence, attend rapidly, inflamed tonsils and no cough.


## Sources

- [McIsaac WJ et al. A clinical score to reduce unnecessary antibiotic use in patients with sore throat. CMAJ, 1998](https://pubmed.ncbi.nlm.nih.gov/9475915/)