iRacing Strength of Field: Where to See SOF, How It Works

Strength of field (SOF) is the number iRacing gives each race session to say how strong the grid is. It comes from the iRatings of the drivers in that split. You see it on the race result for each split, in the Results tab of the series page. And it sets how many championship points every finishing position pays.

What iRacing does not give you is the exact maths. Below is what iRacing states officially, what the community formula looks like, and what SOF really changes for you.

Checked on 15 October 2026 against the iRacing Official Sporting Code v.2026.09.09 (dated 9 September 2026), the iRacing support articles "Championship Points" (modified 15 August 2024) and "How are Series and Race Week Points Calculated?" (modified 21 April 2022), the iRacing 101: Championship Points article (15 August 2024), the 2025 Season 2 release notes and the 2024 Season 3 Patch 2 release notes (28 June 2024). Where iRacing has not published something, I say so.

What strength of field means in iRacing

The Sporting Code glossary defines it in one line. SOF is "a value assigned to a Session based on the total iRatings of the drivers in the event." A high SOF comes from a high average iRating, and that can mean more Championship Points paid out.

So SOF belongs to a session, not to you. Your iRating is yours. The SOF is the field you raced against.

Two things follow from that.

• Every split has its own SOF. When too many drivers register for one race time, iRacing splits them into separate fields that race at the same time. Section 6.5.2 says drivers are placed in a split based primarily on their iRating at the start of the race. So the top split carries the highest SOF and the last split the lowest. If splits are new to you, I go through them in how the iRacing race splits system works.
• Every car class has its own SOF. In multiclass races the June 2024 Data API change added a strength of field and an entry count for each car class in the results. A GTP driver and a GT3 driver in the same session are not measured against the same number.

How to see strength of field in iRacing

iRacing has not written a support article that walks you through every place SOF appears. Here is what its own documents confirm.

On the race result

This is the main place. Since the 2025 Season 2 redesign, each official series page has a Results tab. iRacing's release notes describe it as showing "the results for each split of an official series, separated by timeslot." Open the timeslot you raced, pick your split, and the result for that split carries its SOF.

iRacing's own weekly race recaps quote the SOF of each split they report on, and that number comes from the same result.

On the series page

The same 2025 Season 2 update added a Series Insights tab with "general stats, graphs, and heatmaps" for each series. Press coverage at the time (Overtake) reported that it shows the strength of field of the top split. iRacing's own notes do not list SOF by name, so check the tab yourself rather than take that as official.

In the sim

I could not find any iRacing documentation of an official SOF readout inside the sim, in the black boxes or on the timing screen. The live SOF numbers you see in many streams come from third-party overlays. They read every driver's iRating from the session and run the community formula below. Treat them as estimates. If you want one, I compare the main tools in the best iRacing apps and set one up in the SimHub overlay guide.

Through the Data API

If you build your own tools: the 2024 Season 3 Patch 2 notes (28 June 2024) added strength_of_field and num_entries to each car class in the event results of the Web Data API. That is the official per-class SOF, straight from iRacing.

How SOF is calculated: what iRacing says

Here is every official line I could find, word for word where it matters.

That is it. No formula, no constants, no worked example. The support article says "averaging", but iRacing never says which kind of average, and the glossary talks about the "total" iRatings in the same breath. That gap is where the community formula comes from.

The community SOF formula

This formula is community-derived. iRacing has not published or confirmed it. It has been passed around sim racers for years, and it sits behind community spreadsheets like the "iRacing SOF iRating Calculator" shared in the SIMRacingApps project in 2019. Use it as an estimate, not as iRacing's code.

It works in three steps.

1. Base number. BR = 1600 / ln(2). That is about 2308.3.
2. Each driver's exponential. For every driver, take e to the power of (minus their iRating divided by BR).
3. Field SOF. Add up all those exponentials. Divide the number of drivers by that sum. Take the natural log of the result and multiply by BR.

Written out: SOF = BR × ln( N / Σ e^(−iR / BR) ).

You do not need to love the maths. You need to understand what it does: it weights the field toward its lower ratings. One very fast driver lifts the SOF far less than a plain average would.

I ran a few fields through it to show you.

Look at the last row. One 6000 driver joins a 1500 field. A plain average says the field jumped by 225. The community formula says about 100. That fits the racing: one alien at the front does not make the other 19 drivers any quicker.

How SOF affects championship points

This part is official and clear. Section 5.6.1 of the Sporting Code sets out three rules.

1. SOF sets the value of the race. Races are valued by the strength of field. "The higher the SOF, the more points are available for each finishing position."

2. Field size sets the spacing. "The larger the field, the smaller the difference in Race Event Points awarded for each finishing position." iRacing's own example: with the same SOF, second place in a 20-car field earns more than second place in an 8-car field.

3. Only your best races count. Each race week, iRacing averages the best 25% of your race results, rounded up. Run 9 official races and your best 3 are averaged. Run 4 or fewer and only your best one counts. Then your best 8 race weeks of the normal 12-week season make your season total.

What iRacing does not publish is the points table itself. There is no official figure for "an SOF of X pays Y to win". iRacing's recaps quote what a given winner scored, but that is a result, not a formula.

A few edge cases from the Sporting Code:

• Unofficial races do not count. A ranked race needs enough starters to go official. Section 6.3.1 says the minimum is typically 6 drivers, but that is a guide, not a rule. If it does not go official, iRating does not move and those points are not part of your week.
• Time trials have no SOF. Section 5.6.2.2 says it plainly: time trial points are awarded linearly and "Strength of field is not calculated." The fastest driver gets 100 points.
• You race for points against everyone, but rank against your division. Each ranked series splits non-rookie drivers into 10 divisions by iRating, plus an 11th division for rookies. You collect points against whoever is in your split, then you are ranked inside your division.

What is a good SOF?

Here I have to be straight with you. iRacing does not publish a "good" SOF for any licence class, and I have not found a source I would put my name to.

The reason is simple. SOF comes from iRating, and the Sporting Code says iRating "does not impact a driver's License Class." An A licence driver can sit on 1500 iR and a D licence driver on 3000. Licence class tracks safety and progress. iRating tracks pace and results. Rookies cannot even see their own iRating (section 4.1.5).

So there is no honest SOF number per licence. The useful comparison is within one series and one week:

• Compare against the top split of the same timeslot. That tells you how close you are to the front of that series.
• Compare against your own iRating. If the SOF is well above your number, a mid-pack finish is a good result and the points reflect it. If it is well below, you are expected to win, and iRating will punish anything else.
• Do not compare across series. A popular GT3 series and a small open-wheel series draw very different grids at the same time.

If you want to move up the splits for real, the work is on your iRating and your consistency. I cover that in how to rank up in iRacing and how to raise your safety rating. And if you have been told to drop your iRating to get easier splits, read why tanking iRating is a bad idea first. The Sporting Code bans it (8.1.1.10).

FAQ

Where do I find the strength of field of my iRacing race?

On the race result for your split. Open the series, go to the Results tab, pick the timeslot and then your split. Each split has its own SOF. Developers can also pull it per car class from the Data API.

How does iRacing calculate strength of field?

Officially, iRacing only says SOF is based on the iRatings of the drivers in the field, and its support pages call it an average. The exact formula is not published. The widely used community formula is an exponential average with a base of 1600/ln(2), which weights the field toward its lower ratings.

Does a higher SOF give more championship points?

Yes. The Sporting Code says the higher the SOF, the more points are available for each finishing position. Field size matters too: bigger fields mean smaller gaps between positions.

Is SOF the same as average iRating?

iRacing's support article calls it an average of iRatings but never says which kind. The community formula is an exponential average, which comes out lower than a plain average when the field is spread out. iRacing has not confirmed either.

Can I see SOF during a race in the sim?

I could not find an official in-sim SOF display in iRacing's documentation. Third-party overlays show a live estimate calculated from the iRatings of the drivers in your session.

What is a good SOF for my licence class?

iRacing does not publish one. SOF is built from iRating, and iRating has no effect on licence class. Compare SOF within the same series and week instead, and against your own iRating.