Considered Compensation from W2

401k/profit sharing plan.  Owner's 2025 W2 showing $96,143 in Box 1 and  $99,999.90 in Box 3 & Box 5.  Their pre-tax deferral amount in box 12 is $20,150.  In addition, their 2% S-corp shareholder employee health insurance premium of $16,293.32 is in Box 14 (other).  To get to their considered compensation for their safe harbor/profit sharing contributions do I add $96,143.22 + $20,150 + $16,293.32?  For some reason this one is confusing me.  TYIA! 

As always, much turns on the plan’s definition of benefit compensation. Does the plan’s definition include the employer’s payment for health insurance?

If so, is compensation $116,293.22 [$99,999.90 + $16,293.32]?

The difference between the $20,150 § 401(k) non-Roth elective deferral and a $16,293.32 income recognition for the employer’s payment for health insurance seems to be the $3,856.68 difference between box 3&5 wages [$99,999.90] and box 1 Federal income tax wages [$96,143.22].

2% Shareholder premiums are generally already included in the box 1 figure.

This is one reason why it is good to cross check comp on payroll reports against the actual W-2. Payroll reports through out the year do not usually include the 2% shareholder premium, it is tacked onto the final income reporting at year end and reflected on the W-2. An aggregated payroll report for the year may not include it, which it often is needed information to correctly determine Plan Compensation. 

The amount in box 14 is for informational purposes, not tax reporting purposes. 

So if the plan definition of compensation is gross W2 with no exclusions, usually you would take Box1 + pre-tax amounts in box 12. If there are pre-tax amounts NOT reported anywhere on the W-2, such as §125 or employee HSA contributions, those get added as well, because absent the employee's election to put money into those buckets they would have appeared on the W-2. 

Box 3 - I pretty much only use it for HPI determinations unless your plan doc has some interesting definition of compensation. 

Box 5 - this almost always means nothing for plan purposes unless the plan doc has an interesting definition of compensation

Box 1, taxable wages, includes the 2% S-corp shareholder employee health insurance premium of $16,293.32 since it is taxable to the employee, but does not include the pre-tax deferral amount of $20,150 since it is not taxable. On the other hand, Box 3 and 5 do not include the 2% S-corp shareholder employee health insurance premium of $16,293.32 since it is not subject to FICA tax, but includes the pre-tax deferral amount of $20,150 since it is subject to FICA tax. Statutory comp would include both of these items, so if you make the applicable adjustment to each box, you get to the same number (rounding to the integer) - Box 1: $96,143 + $20,150 = $116,293 and Box 3/5: $99,999.90 + $16,293.32 = $116,293. Note Peter's point about checking the document, though. It might exclude the 2% S-corp shareholder employee health insurance premium (e.g., exclusion of taxable fringe benefits) for plan/allocation comp purposes, in which case you would use $99,999.90 for computing your employer allocations.