The leading gross-to-net calculation payroll tax software
Symmetry Tax Engine® (STE) is a powerful gross-to-net tax calculation engine to build, embed, and scale your payroll platform with accuracy and automation. Available for U.S. and Canada.
If there’s a tax, we calculate it
Symmetry Tax Engine® accounts for federal, state, and local taxes — including withholding and employer taxes — for over 7,000 taxing jurisdictions. We provide comprehensive coverage for multi-state reciprocity, U.S. territories, and Canada.
Symmetry Tax Engine® covers payroll tax compliance in all 50 states, U.S. territories including Puerto Rico, and Canada.
- 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
The most powerful payroll tax engine in the industry
- 40% of the U.S. workforcehas paychecks powered by Symmetry
With over 1 billion paychecks calculated to date, we’ve handled almost every complex taxation scenario. No other solution has the same time-honed record of reliability and accuracy.
- 132 million+home and work address pairs processed each year
Covers multi-state calculations with reciprocity and nexus while using cutting-edge geocoding technology to determine accurate payroll taxes.
- 3.32 millisecondsaverage time per payroll tax calculation
When running hundreds or thousands of paychecks, every millisecond counts. The tax engine returns 150,000 gross-to-net calculations in just 7.5 minutes for the On-Prem solution.
- 99.99% uptimewith industry-leading security measures
Symmetry Tax Engine® doesn’t store any personal data. API communications are encrypted in transit. Learn about uptime and security practices.
The ONLY Payroll Tax Engine That Explains Every Decision
Symmetry Tax Engine Premium combines real-time regulatory intelligence with AI-driven explanations—so you can trace, understand, and trust every payroll tax scenario with complete transparency. Double your tax expertise and confidence overnight.
![Symmetry Tax Logic]()
AI Chat: Resolve tax inquiries 98% faster. Leverage Symmetry’s proprietary research to resolve tax inquiries with clear, step-by-step explanations.
![Symmetry Guides]()
Research and Notifications: Access a single source of truth. Eliminate manual research by powering your compliance with comprehensive payroll tax program, rate, and filing information with automated change notifications.
![Symmetry Tax Radar]()
Legislative Tax Radar: Stay ahead of the curve. Protect your platform with proactive monitoring and automated notifications for tax regulation updates across all jurisdictions.
![Symmetry Select]()
Expert Success Team: Scale with total confidence. Gain prioritized implementation and optimization guidance with flexible engagement options tailored to your specific technical workflow.
The Symmetry Suite: your single source for
payroll tax confidence.
Level-up with STE Premium
- 7,000+Jurisdictions supported
- 98%Faster support resolution
- 74%Deflected support tickets
Who will love it?
For large employers, payroll, or HCM software providers, payroll taxes are an incredibly complicated, ever-changing burden to keep up with. Companies can effortlessly ensure employee and employer taxes are accurately calculated by Symmetry’s payroll tax APIs and software tools.
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
"As a Symmetry customer for over 4 years, we have seen a level of partnership, expertise, and organizational excellence enhanced yearly. Engaging and service excellence put them in a class by themselves."
Product Management at a leading information technology company"The biggest challenge we faced as an organization was how do we build and maintain a payroll calc engine that supported federal, state, and local calculations at a price point that was both effective and efficient for our business."
The nuts and bolts
Built by developers for developers, STE offers the flexibility of a Web API or an On-Premise SDK. Both versions provide the same world-class engine, the difference is your deployment preference.
Web APIrecommended
On-Premise Software Development Kit (SDK)
Symmetry Location Service for Local Taxes
The STE uses the Symmetry Location Service to calculate taxes based on an employee’s home and work address. Location codes never change and are based on the Geographic Names Information System (GNIS), the federal standard for geographic nomenclature.
"LocationCodeRequest": {
"locationName": "Symmetry",
"address": {
"streetAddress1": "14350 N 87th St",
"streetAddress2": "Ste 310",
"city": "Scottsdale",
"state": "AZ",
"zipCode": "85260"
}
}Payroll tax tools for every stack
The STE contains nine different interfaces to suit your development preferences. These interfaces allow the STE to integrate with your development language.
| Language | Web API | On-Premise SDK | |||
|---|---|---|---|---|---|
| Language | Web API | Windows 32‑bit | Windows 64‑bit | Linux 64‑bit* | macOS** |
| JSON | Yes | Yes | Yes | Yes | Yes |
| XML | Yes | Yes | Yes | Yes | Yes |
| C/C++ | No | Yes | Yes | Yes | Yes |
| Java | No | Yes | Yes | Yes | Yes |
| .NET | No | Yes | Yes | No | No |
| .NET Core | No | No | Yes | Yes | Yes |
| Delphi | No | Yes | No | No | No |
*The STE supports both AMD64 (x86_64) and ARM64 architectures for Linux.
**The STE universal macOS binary supports both the AMD64 (x86_64) and ARM64 (M1/M2) architectures.
FAQ
Contact us if you don't find your question answered here about Symmetry Tax Engine®.
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Looking for more?
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Calculate gross-to-net payroll taxes to build or enhance a payroll product, embed payroll into an existing application, and increase compliance.
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Determines complicated local withholding tax rates within your product by applying latitude and longitude coordinates of a residential address and a work address against Symmetry’s expansive library tax shapefiles, nexus and reciprocity algorithm.
Symmetry Payroll Forms
Directly integrates and automates the withholding forms process at the federal, state, and local levels with over 130 compliant forms.