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How Is Workers’ Compensation Calculated?

How Is Workers’ Compensation Calculated?

For the majority of small businesses, workers’ compensation insurance is simply an unavoidable cost. The exact requirements vary by state, but any company that needs coverage faces a simple scenario – carry workers’ comp insurance or face the consequences.

While workers’ compensation coverage is a must for many small businesses, figuring out how much your business will owe is complicated. The exact rates can change every year and there are a variety of factors that impact how much workers’ compensation will cost your business. Let’s break down what impacts your workers’ compensation rates (and what you can do to save on these costs).

How To Calculate Workers’ Comp Rates For Your Business

The first step toward understanding workers’ compensation rates is to identify what factors directly impact premiums. There are three main elements that insurance companies use to calculate your workers’ compensation rate:

  • Workers’ compensation classification codes
  • Payroll
  • Experience modification number

Workers’ compensation classification codes

Your business’ line of work plays a major role in determining your workers’ compensation rates. Insurance companies use class codes assigned by the National Council on Compensation Insurance (NCCI) to adjust your rates. These three- or four-digit codes represent the overall risk level for different types of work.

Insurance agents and underwriters use this information to adjust your overall costs based on your line of business. As you may expect, class codes that indicate greater risk will typically yield higher workers’ compensation insurance premiums. For example, an electrician will be more expensive to cover than an office worker.

While many states use NCCI codes for their workers’ compensation rate calculations, some locations can complicate these calculations. There are several states that use their own code system, meaning that your rates could vary from the NCCI’s rules and regulations if your business is located in the following states:

  • California
  • Minnesota
  • New York
  • North Carolina
  • Massachusetts
  • Pennsylvania
  • New Jersey
  • Delaware
  • Indiana
  • Michigan

To complicate matters even further, there are four monopolistic states: Ohio, Washington, Wyoming, and North Dakota. These states have special legislation in place where workers’ compensation coverage is only provided through a state program. For example, employers in Ohio must go through the Bureau of Workers’ Compensation (BWC) for workers’ compensation insurance by themselves or with a partner like a Professional Employer Organization. This difference means there is no open market for workers’ compensation insurance and the states may use separate class codes from the NCCI.


While class codes impact your insurance rates based on risk factors, your payroll serves as the basis for your overall costs. Class code rates are assigned a dollar amount for every $100 of payroll, so your overall costs will naturally increase along with your total payroll.

Of course, the rates will make a major difference in just how much you owe. Let’s imagine that you need workers’ compensation coverage for an employee making $50,000 a year. If that employee’s rate was $1.50 per $100, those costs would amount to $750 for that salary. Meanwhile, a higher rate of $15 per $100 will bump those premiums up to $7,500 for that one employee.

Experience modification number

Your business’ past also plays a part in your exact rates. Insurance companies factor in your overall workers’ compensation claims history and workplace safety into their calculations. In short, safer businesses with fewer, less severe claims will end up paying less than a similar business with more past incidents or infractions.

The way insurance companies take your business’ experience and loss history into account is through your experience modification number, also known as a MOD. In general, agents and underwriters will look at your last three years of claims data, such as the type, severity, and frequency of claims to assess your overall risk level. The resulting MOD is then used as a multiplier in the following way.

  • Class code rate x (Annual payroll/$100) x MOD = Your business’ workers’ compensation premium

If a business meets the expected losses for their type of work, they’d receive a MOD of 1.0 that won’t impact the calculation at all. Businesses with more losses than expected will have a MOD greater than 1.0, while businesses with a good claims history will have lower MODs. These MODs can drastically impact your overall costs. For example, a MOD of 0.8 will cut your premiums by 20%, while a MOD of 1.2 will increase them by 20%.

Lower Your Workers’ Comp Costs With GMS

Calculating your company’s workers’ compensation rates is a complex process, but that doesn’t mean lowering them has to be difficult for small business owners. GMS is a PEO that partners with businesses to save them time and money by taking on critical administrative burdens for them. That partnership includes utilizing cost containment and loss prevention strategies to help you lower your workers’ compensation rates.

GMS partners with businesses of all sizes to minimize exposure through workplace safety and expert claims management. Our experts work directly with you to limit the potential for workplace injuries or illnesses through safety training and risk assessments. Meanwhile, we’ll be there to quickly and properly manage claims to control extra costs and protect your business.

Ready to lower your workers’ comp premiums and focus on growing your business? Contact GMS today to workers’ compensation risk under control.

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