How to read your paystub and understand how the various types of deductions do (or do not) reduce your taxable income (and what taxable income really means)!

Not all dollars are taxed equally

In case you’ve ever been curious about all that information on your paystub (because maybe you couldn’t sleep one night and needed something to think about), here’s a quick intro guide on what many of those data points are showing! 

In this blog post I specifically want to highlight how your dollars are taxed. They’re not all taxed equally, and that is often surprising for people to learn. I know it was for me! At least being somewhat familiar with the concepts here can be helpful during our financial planning conversations. And who knows, you might be able to help a friend, co-worker or family member unravel their paystub after reading this 🙂 

How are the ways in which dollars are (generally) taxed/not taxed (this is written assuming you have a W-2 job). State taxes have been excluded from this post.

Terms to know: 

Deductions: Amounts that reduce your gross pay. They can be pre- or post-tax.

FICA Tax: Federal Insurance Contribution Act. It’s the combination of Social Security and Medicare. The Social Security portion of FICA is 12.4% of your pay. As the employee, you pay 6.2% of that and your employer pays the other 6.2%. The Medicare portion of FICA is 2.9% of your pay with half of that (1.45%) being paid by you as the employee and the other 1.45% paid by the employer. Self-employed individuals pay both employee and employer portions. There is an additional Medicare tax for some higher income earners.

Federal Income Tax: The amount of income tax you owe at the federal level, based on our progressive tax system.

Gross Pay: Your gross pay (sometimes referred to as before taxes) is what you earn BEFORE any taxes or deductions are taken out. This is often the number you’re quoted upon being hired or getting a raise. It’s easy to forget about this number because we are more familiar with our net pay (sometimes referred to as after taxes), which is the amount that lands in our bank account every time we get paid. 

Net pay: Gross Pay – pre-tax deductions – post-tax deductions – taxes = net pay

Taxable Income: This can refer to the income that is taxable for the purposes of FICA and/or Federal and State Income Tax. It’s this definition that we’re attempting to clarify here in this article.

Let’s talk about the deductions that take place BEFORE FICA is calculated (pre-tax deductions):

Most employer-sponsored health insurance premiums that employees pay through  payroll are pre-tax. This means they are deducted BEFORE any taxes are calculated, to include FICA.

So if you have $5,000 of gross earnings this month, and your health insurance premium is $200, your earnings for purposes of figuring FICA taxes, federal and state taxes have now been reduced to $4,800. Reference the charts  below for examples (on an annualized basis).

HSA, FSA, and medical/dental plan premiums are also pre-FICA deductions. Not only are these examples not subject to FICA they are also NOT subject to federal income taxes.

Then there are some deductions that are NOT subject to federal income tax, but ARE subject to FICA:

If you have a workplace retirement account such as a traditional 401k, and you contribute to it, the dollars you contribute are not taxed for federal income tax purposes. These contributions ARE subject to FICA Taxes. In fact, when you review your W-2 at tax time you’ll notice the amount listed in box 1 (Wages, Tips, Compensation) is your gross wages minus whatever amount you contributed to your traditional 401k (and other contributions, for example to an HSA if you have one); but in boxes 3 and 5 (Social Security and Medicare Wages) you’ll see a different number – this number reflects contributions to a 401k since those contributions are subject to FICA.

 These deductions are generally considered “pre-tax” and are excluded from the following taxes:
PRE-TAX DEDUCTIONS:FICAFederal
Employee paid health insurance premiumsYesYes
HSAYesYes
FSAYesYes
Vision/DentalYesYes
Traditional 401k ContributionsNoYes*
Roth 401k ContributionsNoNo**

*Traditional 401k contributions are tax-deferred. This means you do not pay taxes on the contributions in the year in which you make the contributions, and those dollars continue to grow tax free until you begin to make qualified withdrawals from the account. It’s at the time of making a qualified withdrawal that you will pay federal income tax.

** Roth 401k contributions are considered after-tax dollars because you pay taxes in the year in which you make the contributions. Because you’ve already paid federal income tax on these contributions, you will not have to pay federal income tax on those dollars upon withdrawal.

Finally, there are deductions that are made AFTER all taxes have been calculated. These are your post-tax deductions.

POST-TAX DEDUCTIONS
These deductions are considered “post-tax” deductions. Meaning FICA and Federal Income Taxes are calculated BEFORE these deductions are made.
Supplemental life insurance
Disability Insurance
Group Legal Plan
Roth 401k Contributions

Here are some examples of how that all works:

PRE-FICA:

Gross Pay$100,000.00
Deductions taken before FICA tax is calculated 
Employee portion of Health Insurance Premium$2,000.00
HSA or FSA Contribution$1,200.00
Vision/Dental Plan Premium$600.00
Total amount not subject to FICA$3,800.00
Wages subject to FICA (often reflected in boxes 3 & 5 of your W2)$96,200.00
The employee portion of Social Security tax at 6.2% and Medicare tax at 1.45% are calculated off of $96,200 and not $100,000 in this example.
*All numbers are annual

PRE-FEDERAL

Gross Pay

 

$100,000.00

Deductions taken before federal income tax is calculated 
Traditional 401k Contribution$10,000.00
All pre-Fica deductions listed in table above$3,800.00
Total amount not subject to federal income tax$13,800.00
Wages subject to federal income tax (W2 Box 1 Wages)$86,200.00
Federal Income Tax is calculated off of $86,200 and not $100,000
*All numbers are annual
  

AFTER-TAX DEDUCTIONS

Gross Pay

 

$100,000.00

Less pre-tax deductions$86,200.00
Deductions taken after taxes have been calculated 
Roth 401k Contribution$10,000.00
Supplemental Life Insurance Premiums$100.00
Disability Insurance Premiums$400.00
Taxes withheld (FICA, Federal, State) … an arbitrary number is used here just to illustrate the process – it is not reflective of the calculations above$2,000.00
Total amount of after-tax deductions and taxes$12,500.00
Net Pay that lands in your bank account$73,700.00
  

*All numbers are annual

Hopefully you found that to be a helpful explanation of how dollars are taxed differently (assuming a W2 paying job). There are so many different benefits at your job from health insurance, to saving on taxes that it can be helpful to reflect from time to time on just what it is exactly you’re getting from all that hard work!

 

Form 5498 and your Roth IRA Contribution

Form 5498 and your Roth IRA Contribution – don’t let this form confuse you!

If you’re new to your FI journey you are likely just getting familiar with the paperwork needed to stay organized (and lots of other things, too! Don’t worry – I’ve got you!). As an advice-only financial planner I help my hybrid-DIYers stay organized on the path to FI. So here’s some quick info on the role the 5498 will play in your organizational system.

It’s that time of year when Form 5498s are sent out by custodians. Because they are sent out after tax season is over, their arrival in your custodian’s dashboard, your in-box or real mailbox can cause confusion about what to do with it.

IRS Form 5498 is titled “IRA Contribution Information”. It can communicate a lot of IRA-contribution-related things. 

Today I want to highlight Form 5498 as it pertains to contributions to your Roth IRA only. I’ll touch on other uses later.

Key points about Roth IRA contributions that will help you understand the purpose of your 5498 for that particular account:

  • You can make a current year contribution to your Roth IRA up until tax day of the following year. For example, for a contribution to count as a 2025 contribution you can do so anytime between January 1, 2025 and April 15, 2026. 
  • When you make a contribution to a Roth IRA that contribution is NOT tax deductible in the current tax year. That’s because the dollars you contributed to your Roth IRA have already been taxed. So having your 5498 prior to tax time is not generally necessary.
  • Box 10 of Form 5498 will show how much you contributed to your Roth IRA for that year.
  • Not all dollars in a Roth IRA are treated the same. They live in 1 of 3 buckets depending on how they got into your Roth IRA:
  1. Contributions
  2. Conversions
  3. Growth

**Keeping your form 5498s is a great way to prove how much of the money in your Roth IRA is considered a CONTRIBUTION so that if you need to withdraw those dollars they are not treated like conversions or growth and possibly taxed/penalized **

This can matter for those on the path to FI who want access to funds in their Roth IRA prior to age 59 ½ (age 59 ½ is the most common qualifier for withdrawing growth from your account tax and penalty free). Whether or not you choose to take money from your Roth IRA is a decision to be carefully considered with the help of your planner. But knowing it’s an option to be explored is a great piece of information for you hybrid-DIYers!

Contributions are yours to take out at any time, for any reason, tax and penalty free. That’s because you’ve already paid taxes on these dollars. So if you and your planner have decided that it makes sense to pull some funds from a Roth IRA prior to age 59 ½ you’ll want to be able to prove to the custodian, should they ask, that the amount you’re asking for is from contribution dollars only (not conversions or growth).

A record of Form 5498s will show this.

Most custodians will keep electronic records available on your dashboard for quite a few years. For example, Schwab keeps them for 10 years.

Keeping your own records as a backup to your custodian is always a good idea!

Resources: IRS Form 5498