> ## Documentation Index
> Fetch the complete documentation index at: https://docs-test.symmetry.com/llms.txt
> Use this file to discover all available pages before exploring further.

# What is Calculators by Symmetry (CBS)?

> An introduction to Calculators by Symmetry (CBS) and the paycheck calculators you can embed in your site or application.

Calculators by Symmetry (CBS) lets you add accurate, compliant paycheck calculators to your website or application. Using Symmetry's tax data, CBS calculates federal, state, and local withholding so your users can estimate take-home pay, gross-up amounts, bonuses, retirement contributions, and more.

CBS keeps its calculations current with the [Symmetry Tax Engine](/ste/overview/what-is-the-ste), so results reflect the latest federal, state, and local tax rules without you maintaining tax logic yourself.

## What you can do with CBS

* Estimate net ("take-home") pay from salary or hourly wages
* Reverse-engineer the gross pay needed to hit a target net (gross-up)
* Model bonuses using flat or aggregate supplemental methods
* Show the paycheck impact of 401(k) and 403(b) contributions
* Calculate final pay, stock option, tuition, and tax tip scenarios

See [Available calculators](/cbs/overview/available-calculators) for the full list.

## The two integration paths

CBS offers two integration paths. Use either on its own, or combine them.

<CardGroup cols={2}>
  <Card title="Widgets" icon="window">
    Symmetry-managed calculators you embed with a single script tag. The fastest way to launch. Configure defaults, theme, and help text inline, by URL, or through the admin console.
  </Card>

  <Card title="API" icon="code">
    Send calculator inputs from your own interface and receive results to display, store, or report on. Use it when you need a custom UI or server-side calculations.
  </Card>
</CardGroup>

Not sure which fits your use case? See [Widgets vs. API](/cbs/overview/choose-path).

## CBS and the Symmetry Tax Engine

CBS provides ready-to-use paycheck calculators for *estimating* take-home pay, gross-up, bonuses, and more. It's powered by the [Symmetry Tax Engine](/ste/overview/what-is-the-ste) (STE), the calculation engine that determines federal, state, and local withholding.

| Use case                                                          | Reach for                |
| ----------------------------------------------------------------- | ------------------------ |
| Show a paycheck estimate on a site, portal, or app                | **CBS** (widgets or API) |
| Run exact payroll withholding as a system of record               | **STE**                  |
| Full payroll tax compliance, reciprocity, and edge cases at scale | **STE**                  |

You don't license STE separately to use CBS; the engine is built in. See [How calculators work](/cbs/core-concepts/how-calculators-work).

## Where to go next

<CardGroup cols={2}>
  <Card title="Widgets quickstart" icon="rocket" href="/cbs/getting-started/embed-a-widget">
    Embed your first calculator widget.
  </Card>

  <Card title="Calculation methods by calculator" icon="calculator" href="/cbs/core-concepts/calculation-methods-by-calculator">
    Understand how each calculator computes withholding.
  </Card>
</CardGroup>