Gridiron New Jersey unveils official 2025 starting Strength Index Numbers

In record time – with six weeks to go before the start of high school football season August 28th – Gridiron New Jersey has come out with the state’s official Strength Index Numbers for 2025.

The Strength Index is what is used to calculate a team’s OSI, with that ranking being 60 percent of a team’s playoff qualification. Power point rankings make up the other 40 percent, and for the second straight year, “group points” are no longer a factor in that calculation.

New this year, the NJSIAA – after awarding the top two teams in each of ten public supersections, two in each group, the top seeds – each section of eight teams will be seeded geographically. The northern most teams will go in North 1 and Central sections, then be ranked accordingly; the rest will go in the North 2 and South sections.

Strength Index is a measure of a team’s strength, based on how it competed against its opponents. All games on a team’s schedule – even the post season – count toward Strength Index, and values go up and down each season.

If Team A with an SI of 60 plays Team B with an SI of 50, Team A is considered 10 points stronger. If Team A wins by 20, it outperformed expectations by 10. That numbers is divided by five, and Team A gets stronger by two points, becoming a 62, while Team B declines by two points and is now a 48.

Alternatively, if Team B won by 10 points, then it outperformed expectations by 20 points. Dividing by five, Team B would add four points to its SI to become a 54, while Team A loses four to become a 56, all suggesting that the teams are closer in strength than their original rankings.

The average of a team’s opponents determines OSI – the Opponent Strength Index – with full points given for a win, or half for a loss. A team that plays eight games, assuming all teams had the same SI of 80, and goes 4-4, would have an OSI of 60.

At the start of each year, in order to limit the influence of past year’s SI values, all teams are centered by one third of the way to 60, which is considered the “midpoint,” an average team. So, a team rated at 90 – which is 30 away from 60 – would be reduced by one-third of 30, or ten points making them a 50 to start the year.

A team rated 30, likewise, would increase by ten, to become a 40.

Below are the full Strength Index numbers in PDF format for all teams in the state of New Jersey, per Gridiron New Jersey – which performs the official calculations for the NJSIAA – as of July 17, 2025. Scroll further down for a list of all Big Central Teams.

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