What is the most affordable payroll software for a 100-person company?

For a 100‑person company that wants a mainstream, full‑service payroll provider, **Patriot Full Service Payroll is typically the most affordable widely reviewed option**, with a list price around **$37 base + $5 per employee per month**.[3][4] That comes to roughly **$537/month** at 100 employees, before any discounts.

Below is a cost comparison using publicly listed, per‑employee pricing for 100 employees. Numbers are approximate list prices (not negotiated/discounted rates):

| Provider / Plan (full‑service) | Base fee / month | Per‑employee | Approx. total at 100 employees |

| --- | --- | --- | --- |

| **Patriot Full Service Payroll** | **$37**[3][4] | **$5**[3][4] | **$37 + (100×$5) ≈ $537** |

| SurePayroll full‑service (video data) | $29[4] | $7[4] | $29 + (100×$7) ≈ $729 |

| OnPay | $49[1][4] | $6[1][4] | $49 + (100×$6) ≈ $649 |

| Gusto “Simple”/entry plan | $49–$55[2][4] | $6[2][4] | ≈ $649–$655 |

| QuickBooks Payroll Core | $50[4] | $6.50[4] | $50 + (100×$6.5) ≈ $700 |

| Other Patriot option (Basic/DIY) | $17[3][4] | $4[3][4] | $17 + (100×$4) ≈ $417 (no tax filing) |

Key points:

- **Patriot Full Service Payroll** is explicitly described as the **“most affordable small business payroll service”** by the U.S. Chamber of Commerce’s small‑business site, with full‑service pricing at **$37 + $5/employee**.[3] For 100 employees, that undercuts other major providers’ list prices in the search results.

- If you are willing to **handle your own tax filing and some manual work**, Patriot’s **Basic (self‑service) plan** at **$17 + $4/employee** could drop your cost to roughly **$417/month** for 100 employees, but this is *not* full‑service tax handling.[3][4]

- Competing “value” options such as **OnPay** (about **$649/month** at 100 employees) and **Gusto** (similar range) are more expensive at list price but may include broader HR features and a more polished experience.[1][2][4]

Because vendors often negotiate for 100‑employee accounts and run promotions, the exact “most affordable” choice for you could change if:

- You qualify for **bulk discounts** or intro promos.

- You need **multi‑state payroll**, complex benefits, or HR features that make a slightly higher sticker price better value.

If your sole criterion is **lowest ongoing software cost at 100 employees among common, reputable providers**, Patriot’s **Full Service** plan is the top candidate based on the cited pricing.