Last updated: March 2026

Pay as you go workers comp: how it works and who should use it

Pay as you go workers comp eliminates the largest cash flow problem in workers compensation insurance. Instead of paying an estimated annual premium upfront based on payroll you think you will run, you pay monthly based on payroll you actually ran. The premium adjusts automatically every pay period. If you hire five people in July, your premium goes up in July. If you lay off three in November, your premium drops in November. No surprise audit bills. No lump sum deposits. No guessing.

For businesses with fluctuating payroll, this is the single smartest change you can make to your workers comp policy.

How traditional workers comp billing creates the audit problem

Under a traditional workers compensation insurance policy, the carrier asks you to estimate your annual payroll at the start of the policy year. They multiply that estimate by the rate for your workers comp class code, apply your experience modification rate, and calculate your annual workers comp premium. You pay that premium upfront or in monthly installments based on the estimate.

At the end of the policy year, the carrier runs a workers comp audit. They compare your actual payroll to your estimate. If your payroll came in higher, you owe additional premium retroactively. If it came in lower, you get a credit. The audit bill arrives months after the policy year ends, which means the cash hit lands when you are not expecting it and cannot budget for it.

I have seen audit bills range from $2,000 for a small office that added a few employees to $25,000 for a construction company that landed a large project midyear and doubled their payroll without updating the carrier. The traditional billing model punishes growth. The more your business expands during the policy year, the larger the audit surprise waiting for you at the end.

When this is wrong: the advice to "just estimate high to avoid audit bills." Overestimating your payroll means you are lending the carrier money interest-free for 12 months. A $5,000 overestimate sitting with the carrier all year is $5,000 you could have used in your business. You get it back as a credit after the audit, but the refund takes 30 to 90 days to process.

How pay as you go changes the math

A pay as you go workers comp policy connects directly to your payroll provider. Every time you run payroll, the system reports your actual wages by workers comp class code to the carrier. The carrier calculates premium on the real numbers and charges you that amount, either as a line item on your payroll invoice or as a separate monthly billing.

The premium tracks reality in near real time. A seasonal business that runs $200,000 in payroll during summer months and $50,000 during winter months pays summer-level premium in summer and winter-level premium in winter. Under traditional billing, that same business would estimate annual payroll at $125,000, pay a level premium all year, and then face an audit adjustment because the actual total was $250,000.

The year-end audit still happens on pay as you go policies. The carrier still reconciles actual payroll against what was reported through the payroll integration. But because the system has been reporting real numbers all year, the gap between reported and actual is typically small. Audit adjustments on pay as you go policies are usually under $500 compared to the $2,000 to $25,000 range on traditional policies.

The tradeoff is that your workers comp cost fluctuates monthly. If you prefer predictable fixed expenses, the variability of pay as you go can complicate budgeting. A construction company that hires 10 laborers for a three-month project sees their workers comp bill jump significantly during those months. The total annual cost is the same as traditional billing, but the cash flow pattern is different.

Who benefits most from pay as you go

Seasonal businesses. Landscapers, restaurants, construction companies, agricultural operations, resorts, and any business where headcount swings 30% or more between peak and off-season. Traditional billing charges you the same premium in January when you have 5 employees as in July when you have 20. Pay as you go charges you for 5 in January and 20 in July.

Seasonal employers overpay workers comp every single off-season month under traditional billing.

Growing businesses. A company that starts the year with 10 employees and ends with 25 gets punished under traditional billing. The estimate was based on 10 employees. The audit catches the additional 15. Pay as you go absorbs the growth incrementally so there is no year-end shock.

Businesses with high turnover. Restaurants, staffing agencies, retail, and hospitality operations where employees cycle in and out frequently. Traditional billing estimates are nearly impossible to get right when your headcount changes every month. Pay as you go tracks the actual number of people on payroll each period.

Startups and new businesses. A new business has no payroll history to base an estimate on. Carriers either require a large deposit or estimate conservatively, which means the new business either overpays upfront or faces a large audit bill at year end. Pay as you go starts from actual payroll on day one.

Sole proprietors and small contractors transitioning from a ghost policy to an active policy. If you have been running a ghost policy with zero payroll and you hire your first employee, pay as you go adjusts immediately. A traditional policy would require a midterm endorsement, recalculated premium, and often a catch-up payment that surprises new employers.

Who should stick with traditional billing

Businesses with stable, predictable payroll. An accounting firm with 15 salaried employees and zero seasonal variation has no reason to switch. Their estimate will be accurate. Their audit adjustment will be minimal. The traditional model works when the estimate matches reality.

Businesses that prefer fixed monthly expenses. Some owners want to know exactly what their workers comp cost per employee will be every month. Pay as you go introduces variability that, while accurate, requires tracking. If your bookkeeping cannot handle a fluctuating workers comp line item, traditional billing with a good estimate is simpler.

When this is wrong: insurance agents who push pay as you go on every client because it is easier to sell. A stable 20 person office pays the same total premium under either model. The only difference is cash flow timing. If the agent is earning a higher commission on the pay as you go product, ask why they are recommending it for a business with no payroll variability.

How to set up pay as you go through your payroll provider

Pay as you go requires your workers comp carrier and your payroll provider to integrate. The payroll system reports wages by class code to the carrier after each payroll run, using the same gross pay figures calculated under IRS Publication 15 withholding rules. Not every carrier works with every payroll provider, so the first step is confirming compatibility.

Gusto offers built-in pay as you go workers comp through partner carriers. The setup happens inside Gusto's platform. You select workers comp during onboarding, enter your business details and class codes, and Gusto connects you with a carrier. Premium is calculated each pay period and added to your payroll invoice. This is the simplest implementation on the market for businesses under 50 employees.

ADP offers pay as you go through their insurance services division. The integration works with ADP's payroll platform and supports a wider range of carriers than Gusto, including large national carriers and state funds. Setup requires coordination between your ADP rep and the carrier, which can take two to four weeks.

Paychex offers a similar integration through their workers comp administration product. The payroll data flows to the carrier automatically, and premium is billed monthly based on actual wages. Paychex also offers a workers comp pay as you go option bundled with their PEO product for businesses that want insurance and payroll under one umbrella.

If your current payroll provider does not support pay as you go integration, you can still get a pay as you go policy by working directly with a carrier or broker. The process is manual: you report your payroll monthly to the carrier (usually through an online portal), and the carrier invoices you based on the reported wages. This adds 15 to 30 minutes of administrative work per month but still eliminates the annual audit surprise.

The workers comp class code issue that pay as you go does not fix

Pay as you go solves the payroll estimation problem. It does not solve the classification problem. If your employees are assigned to the wrong workers comp class code, you are paying the wrong rate on every payroll run regardless of whether the billing is traditional or pay as you go.

Wrong class codes produce wrong premiums on every single payroll run, not just once a year at audit.

A construction company that classifies a project superintendent as clerical (class code 8810, roughly $0.30 per $100 of payroll) when the superintendent spends half their time on job sites (class code 5606, roughly $8 per $100) is underreporting premium by approximately $7.70 per $100 of that employee's payroll. On a $90,000 salary, that is $6,930 per year in underreported premium. The year-end audit catches the misclassification and bills you retroactively regardless of your billing method.

Before switching to pay as you go, review every employee's class code assignment against their actual job duties. Read the full class code descriptions in your state's workers comp manual, not the abbreviated labels on your policy. If your workers comp for contractors includes employees who split time between field work and office work, confirm which code governs. In most states, the employee gets one code based on their primary duties, and the higher rated code usually wins.

What to do this week

Ask your current carrier and payroll provider whether they support pay as you go workers comp integration. If both support it, request a switchover at your next policy renewal. Most carriers allow midterm conversion, but renewal is cleaner because it resets the audit baseline.

If your carrier does not support pay as you go, ask your insurance broker for quotes from carriers that do. The workers comp premium rate will be similar or identical across carriers for the same class code in the same state because rates are regulated. The difference is the billing method and the carrier's audit practices. Your payroll provider also caps Social Security withholding at the SSA annual wage base, but workers comp premium has no such cap and applies to every dollar of payroll.

Pull your last workers comp certificate and check the estimated annual payroll listed on the policy. Compare it to your actual payroll over the last 12 months. If the gap is more than 15%, you are either overpaying every month (estimate too high) or building an audit bill (estimate too low). Either way, pay as you go fixes the problem.

When this recommendation changes: employers with fully remote teams in low-risk class codes and stable headcount. The audit adjustment on a 10-person remote company under class code 8810 is typically under $200, which means pay as you go saves you almost nothing while adding integration complexity.

Written by a Certified Payroll Professional with 30 years of experience.

This is not legal or financial advice. Consult a qualified professional for your specific situation.