US Taxes and other Contributions
- Sigrid Kviteberg
- Helen Ustych
- Valentyna Herasymova
This article describes how to set up the rates for calculating US taxes, Social Security, Medicare,etc.
- 1 Introduction
- 2 Social Security, Medicare Taxes and 401(k) Contribution Rates
- 2.1 2025
- 2.2 2024
- 2.3 2023
- 2.4 2022
- 2.5 2021
- 2.5.1 Social Security Tax Rate
- 2.6 2020
- 2.6.1 Social Security Tax Rate
- 2.6.2 Medicare Tax Rate
- 3 Federal Income Tax
- 4 Import Tax def files
Introduction
For the latest information about developments related to Pub. 15-T, such as legislation enacted after it was published, go to About Publication 15-T, Federal Income Tax Withholding Methods | Internal Revenue Service
Prior year forms and instructions | Internal Revenue Service - forms for previous years.
Social Security, Medicare Taxes and 401(k) Contribution Rates
Tax rates and the social security wage base limit. Social Security and Medicare taxes have different rates and only the social security tax has a wage base limit. The wage base limit is the maximum wage subject to the tax for the year.
Rates: (reference: 2020 Publication 15 (irs.gov), Publications 15T, Recent 15T)
2025
Social Security Tax Rate
Social Security tax rate is the same as in 2021/22 - 6.2% (amount withheld) each for the employer and employee (12.4% total)
Social Security wage base limit has increased to $176,100 (from $168,600 in 2024)
Medicare Tax Rate
Medicare and Additional Medicare tax rates and limits (Additional Medicare) stay the same as in years 2020/ 2021/2022:
1.45% (amount withheld) each for the employee and employer (2.9% total)
There is no wage base limit for Medicare Tax; all covered wages are subject to Medicare Tax
Additional Medicare Tax withholding
0.9% Additional Medicare Tax in excess of $200,000 in a calendar year
No employer share for Additional Medicare Tax ( go to this site for other information about additional Medicare Tax http://IRS.gov/ADMT )
401k Pension Plan Contribution Rate
401k Contribution limits have increased to $ 23 500 (from $ 23 000 in 2024)
401k Catch-up limit remains the same - $ 7 500
2024
Social Security Tax Rate
Social Security tax rate is the same as in 2021/22 - 6.2% (amount withheld) each for the employer and employee (12.4% total)
Social Security wage base limit has increased to $168,600 (from $160,200 in 2023)
Medicare Tax Rate
Medicare and Additional Medicare tax rates and limits (Additional Medicare) stay the same as in years 2020/ 2021/2022
401k Pension Plan Contribution Rate
401k Contribution limits have increased to $ 23 000 (from $ 22 500 in 2023)
401k Catch-up limit remains the same - $ 7 500
2023
Social Security Tax Rate
Social Security tax rate is the same as in 2021/22 - 6.2% (amount withheld) each for the employer and employee (12.4% total)
2. Social Security wage base limit has increased to $160,200
Medicare Tax Rate
Medicare and Additional Medicare tax rates and limits (Additional Medicare) stay the same as in years 2020/ 2021/2022
401k Pension Plan Contribution Rate
401k Contribution limits have increased to $ 22 500 (from $ 20 500 in 2022)
401k Catch-up limit has increased to $ 7 500 (from $ 6 500 in 2022)
2022
Social Security Tax Rate
Social Security tax rate is the same as in 2021 - 6.2% (amount withheld) each for the employer and employee (12.4% total)
Social Security wage base limit is $ 147 000
Medicare Tax Rate
Medicare and Additional Medicare tax rates and limits (Additional Medicare) stay the same as in years 2020/ 2021
401k Pension Plan Contribution Rate
401k Contribution limit has increased to $ 20 500 (from $ 19 500 in 2020)
401k Catch-up limit remains the same - $ 6 500
2021
Social Security Tax Rate
Social Security tax rate is the same as in 2020 - 6.2% (amount withheld) each for the employer and employee (12.4% total)
Social Security wage base limit is $ 142 800
2020
Social Security Tax Rate
Social Security tax rate is 6.2% (amount withheld) each for the employer and employee (12.4% total)
Social security wage base limit is $137,700
Medicare Tax Rate
1.45% (amount withheld) each for the employee and employer (2.9% total)
There is no wage base limit for Medicare Tax; all covered wages are subject to Medicare Tax
Additional Medicare Tax withholding
0.9% Additional Medicare Tax in excess of $200,000 in a calendar year
No employer share for Additional Medicare Tax ( go to this site for other information about additional Medicare Tax IRS.gov/ADMT)
Top organization unit > Rates: define Global Rates used for calculation of US taxes and contributions:
Federal Income Tax
Tax Tables on Regular Wage
There are two rate options to follow for automated payroll.
STANDARD Withholding Rate Schedules (Use these if the Form W-4 is from 2019 or earlier, or if the Form W-4 is from 2020 or later and the box in Step 2 of Form W-4 is NOT checked)
Form W-4, Step 2, Checkbox , Withholding Rate Schedules (Use these if the Form W-4 is from 2020 or later and the box in Step 2 of Form W-4 IS checked)
Tax Rate on Supplemental Wage
Supplemental wages combined with regular wages
If you pay supplemental wages with regular wages but don't specify the amount of each, withhold federal income tax as if the total were a single payment for a regular payroll period.
Supplemental wages are identified separately from regular wages
If you pay supplemental wages separately (or combine them in a single payment and specify the amount of each), the federal income tax withholding method depends partly on whether you withhold income tax from your employee's regular wages.
If you withheld income tax from an employee's regular wages in the current or immediately preceding calendar year, you can use one of the following methods for the supplemental wages:
Withhold a flat 22% (no other percentage allowed).
If the supplemental wages are paid concurrently with regular wages, add the supplemental wages to the concurrently paid regular wages and withhold federal income tax as if the total were a single payment for a regular payroll period.
Note: the flat Tax Rate on Supplemental Wages is hardcoded in the Tax Defition file and can be updated by Adonis support if the Rate changes, though it has stayed the same for many years now.
Every year the US tax rates are updated, to maintain the correct calculations in Adonis, when a new payroll year is opened, a new Tax Definition file must be imported to the system. Though the new rates are never published before the year starts, and normally are either published in January or even later, to keep the calculations running in Adonis the Tax Definition file still has to be updated and imported to the system.
After the new rates are published, Adonis will create a new file for import. Please see files below by year.
2025 .Def Tax file
2024 .Def Tax file
2023 .Def Tax file
2020 .Def Tax file
2021 .Def Tax file
2022 .Def Tax file
Import Tax def files
The Tax file should be imported to all the installations - Office and Vessels as it does not replicate.
To import the tax definition file you have to do the following steps:
Download the file for the correct year from this article and store it somewhere you can access it
Go to Payroll | Tax Def Files | Import
Find the file and click Open