**Net Run Rate (NRR)** is a statistical metric used in cricket tournaments to rank teams that are tied on total points in a league standings table. It measures how fast a team scores runs compared to how fast they concede runs throughout a tournament.
---
How Net Run Rate Is Calculated
NRR is calculated by subtracting a team's **average runs conceded per over** from their **average runs scored per over** across all matches in a tournament.
$$\text{Net Run Rate (NRR)} = \left( \frac{\text{Total Runs Scored}}{\text{Total Overs Faced}} \right) - \left( \frac{\text{Total Runs Conceded}}{\text{Total Overs Bowled}} \right)$$
---
Important Rules Governing NRR
### 1. The All-Out Rule
If a team is **bowled out (all out)** before using their full quota of overs (e.g., bowled out for 120 runs in 15 overs during a 20-over match), the calculation **still uses the full allotted overs** (e.g., 20.0 overs) for that innings.
* **Why?** This heavily penalizes getting bowled out early, as it lowers the team's scoring rate across the full duration of the innings.
### 2. Conversions for Partial Overs
In cricket notation, partial overs are written using dots representing legal balls (e.g., 18.3 overs means 18 overs and 3 balls). For mathematical NRR calculations, the balls are converted into fractions of an over:
* $18.1\text{ overs} = 18 + \frac{1}{6} = 18.167\text{ overs}$
* $18.3\text{ overs} = 18 + \frac{3}{6} = 18.500\text{ overs}$
* $18.5\text{ overs} = 18 + \frac{5}{6} = 18.833\text{ overs}$
### 3. Abandoned & Rain-Affected Matches
* Matches that are completely **abandoned without a ball bowled** do not count toward NRR.
* If a match is decided using the **Duckworth-Lewis-Stern (DLS) method**, the adjusted targets and revised overs are used for the NRR calculations for both teams.
---
Example Calculation
Imagine Team A plays a 20-over T20 match:
1. **Innings 1:** Team A scores **180/5** in **20 overs**.
2. **Innings 2:** Team A bowls out Team B for **120** in **16 overs** (which counts as 20 full overs under the All-Out Rule).
* **Run Rate For:** $\frac{180 \text{ runs}}{20 \text{ overs}} = 9.00$
* **Run Rate Against:** $\frac{120 \text{ runs}}{20 \text{ overs}} = 6.00$
* **Team A's Match NRR:** $9.00 - 6.00 = \mathbf{+3.00}$
---
Reading the Values
* **Positive NRR (+):** The team scores faster overall than it concedes runs (indicates strong tournament performance).
* **Negative NRR (-):** The team concedes runs at a faster rate than it scores them.