Symmetry Software
Symmetry Tax Engine®
The gold standard in gross‑to‑net calculations.
The Symmetry Tax Engine (STE) is a powerful payroll processing and tax calculator perfect for building or enhancing a payroll platform, increasing compliance and accuracy, and eliminating manual processes.
If there’s a tax, we calculate it.
The STE accounts for federal, state, and local taxes— both withholding and latent employer taxes — for over 7,400 taxing jurisdictions and the U.S. territories. Employer taxes and multi-state processing are accounted for as well.
The Symmetry Tax Engine covers all 50 states, Puerto Rico, and U.S. territories.
- Federal withholding
- FICA (Social Security & Medicare)
- Paid family & medical leave
- SDI/VDI/Employee SUI
- Courtesy withholding
- FUTA & SUTA
- Benefits and pre-tax benefit rules, down to the local tax
- Various other employer taxes
- City
- County
- School district
- Municipality
- Earned income taxes
- Privilege taxes
- Local services taxes
- JEDDs/JEDZ
New! Now available in a Canadian STE version.
The most powerful payroll tax engine on the market.
Runs at an average of 3.32 milliseconds per calculation with over 7,400 taxes, each with its own unique tax ID. Performs over 150,000 gross-to-net-calculations in 7.5 minutes on a Xeon Server.
"wages": [{
"locationCode": "34-017-877450",
"wageType": "Regular",
"calcMethodRegularWages": "Annualized",
"calcMethodSupplementalWages": "None",
"hours": 40,
"grossWages": 1000,
"mtdWages": 0,
"qtdWages": 0,
"ytdWages": 0
}],Innovative payroll tax technology.
Covers multi-state calculations while also using cutting-edge geocoding technology to determine accurate payroll taxes for work and home addresses to rooftop precision. Normalizes addresses while reciprocity and nexus settings are applied.
We put security first.
The Symmetry Tax Engine does not store any personal data or personally identifiable information. All input data is validated as a protective measure. API communications are also encrypted in-transit and an API Key is utilized for authorization.
Who will love it?
For large employers, payroll, or other software providers, payroll taxes are an incredibly complicated, ever-changing burden to keep up with. By licensing Symmetry’s payroll tax software tools, companies can ensure employee and employer taxes are properly calculated and managed.
Who you are
- Entrepreneur
- Software Developer
- Payroll or HR Service Provider
- Large Employer
- Payroll Manager
- Payment Company
What you do
- Building a payroll system from scratch
- Processing payroll in-house
- Adding payroll to your existing offering
- Expanding to new geographic markets
- Building a next-generation payroll system
- Supplementing calculations that don’t deliver all applicable payroll taxes
I got a ton of assistance from the team researching some issues with Kentucky locals. The team is very responsive, thoughtful, and helpful. Great job!Shelly A. Abril, Payroll Tax Compliance
Millions of paychecks are written every week using the Symmetry Tax Engine. Take Symmetry Software for a test drive.
The nuts and bolts.
The Symmetry Tax Engine introduces more flexibility for implementation as well as additional features, including options for a web API or on-premise SDK. With either version you get the same great engine, the difference is where it’s installed and who does the testing and updating.
Web APIrecommended
On-Premise Software Development Kit (SDK)
Location Code Service
The STE uses location codes to calculate taxes based on an employee’s home and work address. They consist of three parts: state number, county number, and feature ID (city, municipality, township, etc.).
Location codes never change and are based on the Geographic Names Information System (GNIS), the federal standard for geographic nomenclature. Learn more about the STE’s geocoding process.
Interfaces
The STE contains nine different interfaces to suit your development preferences. These interfaces allow the STE to integrate with your development language.
Get in touch with us. We are here to help.
On-Premise SDK | ||||
|---|---|---|---|---|
| Web API | Windows 32‑bit | Windows 64‑bit | Linux 64‑bit | |
| JSON | Yes | Yes | Yes | Yes |
| XML | Yes | Yes | Yes | Yes |
| C/C++ | Yes | Yes | Yes | |
| Java | Yes | Yes | Yes | |
| .NET | Yes | Yes | ||
| .NET Core | Yes | Yes | ||
| Delphi | Yes | |||
Tax Notification
Track payroll tax rate changes.
All STE customers also receive the Symmetry Tax Notification Service, which includes real‑time updates when a payroll tax changes, supporting documentation from primary sources, tax‑effective dates, and the version of the STE in which the new or updated tax is available.
Take Symmetry Software for a test drive when you start your FREE 30-day trial. No obligation. No reason not to.
STE common questions.
Try our contact form if you don't find your question answered here.
What is a tax engine?
A tax engine is a calculator that accounts for federal witholding, FICA, state withholdings for all 50 states, Puerto Rico, and U.S. territories. A tax engine also accounts for local taxes, employer taxes, multi-state processing, and various other payroll-related witholdings. The Symmetry Tax Engine is the gold standard in payroll tax withholding software, and essential to your gross-to-net calculation needs.
Who needs a tax engine?
Anyone building a payroll solution from scratch or looking to improve their existing payroll or HCM platform can benefit from the Symmetry Tax Engine. This includes software developers, payroll service providers, large enterprises managing their own payroll, and anyone else looking for a gross-to-net calculation.
Does the Symmetry Tax Engine store any personal data?
No, the STE does not store any personal data or personally identifiable information. When address and wage information is passed into the STE, the STE performs its calculations and then returns all applicable payroll taxes back without storing any of the employee data. No employee data is ever stored with Symmetry Software.
Can I replace my existing tax engine with the Symmetry Tax Engine?
Yes! Every year, we have clients replace their existing payroll tax software with the Symmetry Tax Engine. Contact us today to learn how we can help you make the transition.
How often is the STE updated?
Our team of taxation experts and software engineers will support you with timely and accurate updates to the tax engine. We understand that taxes change frequently and compliance is imperative. The STE on-premise SDK is released monthly, with interim releases during parts of the year when taxes change more frequently. The STE Web API is released more frequently. STE Web API customers have access to a staging server to see updates in advance of them moving to production.
Get started.
Looking for more?
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Automate the withholding forms process at the federal, state, and local level with over 125 compliant forms.
Eh?
Canadian Tax Engine
Calculate Canadian withholding for federal and all provinces while accounting for pension plans, employer taxes, multi-province processing, and more.