If you run a one-person S-corp and just need to pay yourself a W-2 salary, file the quarterly forms, and not think about payroll again until next quarter, Gusto Simple is the most defensible default in 2026. It has transparent solo-scale pricing, automatically files federal, state, and local payroll taxes — including Form 941 — and syncs with QuickBooks Online and Xero. Justworks and ADP RUN both do real work, but neither is built around the owner-only S-corp the way Gusto is.
Justworks Payroll is a reasonable alternative if you eventually add a real employee, but Justworks PEO is usually the wrong tool for a solo owner: its PEO membership requires at least two individuals in the company to run payroll, even if one is unpaid. ADP RUN's Essential tier covers the same core filings, but its solo pricing isn't public — you'll be quoting a sales rep instead of comparing numbers on a page. Below is the math, not just the feature list.
Why does a solo S-corp even need payroll software?
Once you elect S-corp status, the IRS requires you to pay yourself “reasonable compensation” as a W-2 employee before taking any tax-free distributions. That salary carries real payroll tax obligations — Social Security and Medicare, split between employee and employer — plus quarterly Form 941 filings and annual W-2s. Get the mechanics wrong and you're not just risking a clerical error; you're risking the IRS reclassifying distributions as wages, which comes with back taxes and penalties.
Payroll software doesn't decide your reasonable compensation number — that's a facts-and-circumstances judgment call best made with a CPA or enrolled agent, based on what you'd pay someone else to do your job. What software does is turn that number into compliant paychecks, tax deposits, and filings, automatically, every pay period.
What does payroll software actually cost against your payroll taxes?
Here's the more useful question than “what's the sticker price”: how much is the software costing you relative to the payroll taxes it's managing? A one-owner S-corp on a $60,000 salary owes a different absolute payroll-tax bill than one on $100,000, and a flat software fee shrinks as a share of that bill as compensation rises.
The federal combined payroll tax rate on wages — Social Security plus Medicare, both employee and employer sides — is 15.3% up to the Social Security wage base, which sits at $184,500 for 2026. All three reasonable-compensation scenarios below fall well under that cap, so the math is simple: multiply the salary by 15.3%.
| Reasonable salary | Combined payroll tax (15.3%) |
|---|---|
| $60,000 | ≈ $9,180 |
| $80,000 | ≈ $12,240 |
| $100,000 | ≈ $15,300 |
Now layer in the annual software cost for a one-owner, one-W-2-employee setup — payroll-only pricing, no benefits add-ons:
| Platform | Annual cost (1 owner-employee) | % of tax at $60K salary | % of tax at $80K salary | % of tax at $100K salary |
|---|---|---|---|---|
| Gusto Simple | ≈ $660/yr | 7.2% | 5.4% | 4.3% |
| Gusto Plus | ≈ $1,104/yr | 12.0% | 9.0% | 7.2% |
| Justworks Payroll | ≈ $696/yr | 7.6% | 5.7% | 4.6% |
| Justworks PEO Basic | ≈ $948/yr (not usable solo) | — | — | — |
| ADP RUN Essential | Quote-based, not published | — | — | — |
The takeaway isn't that software creates savings — it doesn't touch your tax rate. The takeaway is that Gusto Simple and Justworks Payroll both sit in a similar, modest single-digit-percent range of the taxes they're administering, while Gusto Plus costs roughly twice as much for features a single-state solo owner usually doesn't need yet. All figures reflect list pricing as of mid-2026 and can change — check the live pricing page before you commit.
Gusto: the transparent default for solo S-corp payroll
Gusto's biggest advantage for a one-person S-corp isn't a feature — it's that you can see the price before you sign up. As of mid-2026, Gusto Simple runs $49 a month plus $6 per person, which works out to about $660 a year for owner-only payroll. Gusto Plus, at $80 a month plus $12 per person (about $1,104 a year), adds multi-state payroll, next-day pay, time tracking, and benefits administration.
Gusto automatically calculates and files federal, state, and local payroll taxes every time you run payroll, including quarterly Form 941 and year-end W-2s — you're not manually calculating withholding or mailing anything. It also syncs with both QuickBooks Online and Xero, which matters if your bookkeeping already lives in one of those tools.
Where Gusto falls short
- Simple is single-state only — if you move or work across state lines, you'll need to upgrade to Plus.
- You still pay the per-person fee for a single owner-employee; it's not a flat “solo” tier.
- Plus roughly doubles your annual cost for features many single-state solos won't use in year one.
Skip Gusto if…
- You specifically want a PEO relationship with co-employment and pooled benefits.
- You need multi-state payroll on day one and don't mind paying the Plus premium.
- You'd rather negotiate a custom quote with a sales team, which points you toward ADP.
Justworks: solid payroll, but PEO isn't built for one person
Justworks sells two different products that solo owners often conflate. Justworks Payroll, at $50 a month plus $8 per employee (about $696 a year for one owner-employee), is a straightforward payroll product: it supports all 50 states, includes time tracking, and files Form 940, Form 941, W-2s, and 1099s at no extra charge. On paper, that's competitive with Gusto Simple.
Justworks PEO is a different animal, and it's the one solo owners need to be careful about. PEO Basic lists at $79 per employee per month — about $948 a year for a single employee — but Justworks requires at least two individuals in the member company to run payroll, even if one of them is an unpaid owner. If you're truly a one-person S-corp with no other worker, PEO isn't just expensive, it may not be usable at all.
Where Justworks falls short
- The PEO minimum-headcount rule makes the flagship Justworks product a non-starter for many single-owner S-corps.
- The payroll product carries a flat base fee on top of the per-employee charge, a slightly different cost shape than Gusto's.
- An official Xero integration wasn't confirmed at the time of writing — verify directly with Justworks if Xero sync is a dealbreaker.
Skip Justworks if…
- You're a genuine one-person S-corp hoping to use the PEO product — check the current headcount rule before signing anything.
- You don't want a monthly base fee stacked on top of your per-employee cost.
- Xero is your bookkeeping system of record and you need integration confirmed before you commit.
ADP RUN: strong compliance, opaque solo pricing
ADP RUN's Essential package covers the fundamentals you'd expect from a payroll giant: direct deposit, reporting, a general ledger interface, new-hire reporting, W-2/1099 preparation, and tax calculation, filing, deposit, and reconciliation. Enhanced adds state unemployment insurance (SUI) management, which sits outside the Essential tier.
The catch for a solo S-corp: ADP doesn't publish a clean, flat monthly price for Essential the way Gusto and Justworks do. Pricing depends on pay frequency, headcount, and how often you change payees, which means you're requesting a quote rather than comparing a number on a page. That's not necessarily a bad deal — ADP's scale and compliance depth are real — but it makes ADP harder to shop against the other two without picking up the phone.
Where ADP RUN falls short
- No public solo-scale price to compare against Gusto or Justworks — budget time for a sales conversation.
- SUI management, a genuinely useful feature for many small employers, lives in the pricier Enhanced tier, not Essential.
- The overall package is built for a wider range of company sizes, so parts of the feature set go unused at owner-only scale.
Skip ADP RUN if…
- You want to compare exact pricing online before talking to anyone.
- You only need owner-only payroll and a simple bookkeeping sync, without the broader small-business feature set.
- You're not willing to spend time on a sales call to get a number.
Which platform fits your S-corp, by scenario?
Two quick scenarios show how this plays out in practice.
The $60,000 consultant, single state, no other employees. This is the classic solo S-corp: reasonable compensation set modestly, one state, one W-2. Gusto Simple's roughly $660 a year and single-state design match this scenario almost exactly, and the QuickBooks or Xero sync keeps your books clean without a bookkeeper on retainer.
The $100,000 consultant working across two states who's considering a part-time contractor. Here, Gusto Plus or Justworks Payroll both make more sense — you need multi-state handling, and the software cost is a smaller share of a bigger payroll-tax bill (about 7.2% for Gusto Plus, 4.6% for Justworks Payroll, per the table above). If you're already leaning toward a PEO for benefits pooling down the road, this is the point where the Justworks two-person minimum starts to matter less, because you may genuinely be adding staff.
Notice what doesn't change across either scenario: the reasonable-compensation number itself. That's not a software decision — it's a facts-and-circumstances determination the IRS expects you to be able to defend, and it's worth setting with a CPA or enrolled agent before you pick a payroll platform, not after. The same caution applies to how the qualified business income deduction interacts with S-corp wages for a given tax year — treat that as an open question for your tax professional rather than a settled number.
When should you skip payroll software entirely?
Not every solo owner needs a dedicated platform on day one.
- You haven't actually elected S-corp status yet — sole proprietors and single-member LLCs taxed as disregarded entities don't run payroll for themselves, so none of this applies until the election is filed.
- Your CPA or bookkeeper already runs a payroll service bureau as part of your engagement — adding a second platform on top just duplicates cost.
- You're mid-year and about to change entity structure or state residency — it's often cheaper to wait for a clean start than to migrate payroll history twice in one year.
Where payroll software fits in your financial OS
Payroll administration sits in the Flow layer of a solo business's financial stack — it's the plumbing that moves money from business revenue to owner compensation to the IRS, on a predictable schedule. It pairs naturally with your bookkeeping system, your business banking, and the S-corp election decision that made payroll necessary in the first place. If you haven't yet worked through whether an S-corp election makes sense at your income level, that's the step to take before comparing payroll platforms — see our guide to setting reasonable compensation for a solo S-corp and our breakdown of how the QBI deduction interacts with S-corp wages.
Once payroll is running, the natural next stack piece is making sure your bookkeeping actually reconciles against it — our QuickBooks Online review for solo businesses covers that integration in more depth, and our freelancer payroll setup checklist walks through the paperwork you'll need before your first pay run, regardless of which platform you choose.
The bottom line
For most one-person S-corps, Gusto Simple is the platform that costs the least, discloses its price upfront, and files the forms the IRS actually cares about — Form 941 and your W-2 — without extra software layered on top. Justworks Payroll is a fair alternative at a similar price point, especially if you're already leaning toward Justworks for other reasons, but its flagship PEO product is built for companies with at least two people on payroll, not a true owner-only S-corp. ADP RUN brings real compliance depth but asks you to request a quote rather than compare a published price, which makes it harder to evaluate at solo scale.
None of these platforms decide your reasonable compensation number, and none of them replace a CPA when you're setting up the S-corp election in the first place. What they do is turn a number you've already defended into a compliant paycheck, quarter after quarter, for a cost that's a small — and shrinking, as your salary rises — slice of the payroll taxes they're managing.