How Long Does It Take to Switch Accounting Firms, and When Should I Start?
Most owners decide to replace their accounting provider right after a rough stretch. The return went on extension. The numbers came late or didn't match the bank. That frustration peaks in the fall, and fall is the right time to act on it.
The switch itself goes faster than most owners expect. The calendar is the problem. Thanksgiving and the December holidays slow everything down. An owner who starts looking in December usually ends up rushing a transition through the busiest weeks of the year, or starting January with the same problems they wanted to leave behind.
What kind of accounting firm are we talking about?
How long a switch takes depends on what the firm does for you. Replacing a simple service is quick. Moving to a team that runs your whole accounting function takes longer, because there is more to build.
A bookkeeper who codes bank transactions. Often cash basis, working from bank statements. Switching is quick. The new bookkeeper gets access and starts categorizing.
A CPA firm that does your taxes. Some also clean up the books at month-end or year-end. Switching is also quick, since it is mostly access and last year’s return.
An outsourced accounting team. This becomes your accounting department: day-to-day bookkeeping, bills, payroll support, invoicing if you want it, a monthly close, reconciliations and reports you can run the business on. Setting that up takes weeks, because the team documents your processes and builds what was never there.
The extra setup time is the point. A processor touches your books a few hours a month. An accounting team becomes part of how you run the business, with the same people closing your books, reviewing the work and telling you what the numbers mean. This post is about that kind of switch.
How long does it take to onboard a full accounting team?
A simple onboarding can take 2 to 3 weeks. A larger or messier one can take 4 to 8 weeks. The two biggest factors are the size of the business and the condition of the books.
| Your situation | Typical time to take over |
|---|---|
| Under $1M in revenue | A couple of weeks |
| Around $3M in revenue, no major cleanup | About 3 weeks |
| Closer to $10M in revenue | 5 to 6 weeks |
| Books need a major cleanup | Longer. The cleanup comes first. |
| Adding sales invoicing to the handoff | Plan for more than a month |
Smaller businesses move faster because there are fewer accounts, fewer systems and fewer people involved. Sales invoicing is the one workflow that changes the math. You don't have to hand it off. If you do, it is one of the harder pieces to move in under a month, because it touches your contracts, your billing terms and your customers directly.
What happens during the switch?
At Basis 365, every onboarding follows three phases. The timing below is for a simple onboarding:
Kick Off (week 1). A short video call on what to expect and what we need from you.
Onboarding (weeks 2 to 3). A deep dive into your accounting while we set up the systems and documentation we need to run it.
Transition (weeks 3 to 4). Your new team takes over the day-to-day work.
You can see the process in our onboarding overview video.
When should I start looking to be ready by January 1?
Now. Here is how the takeover date shifts depending on when you sign, using a business around $3M in revenue as the example.
| If you sign | What to expect |
|---|---|
| Mid-October | If everything goes smoothly, the new team takes over around November 1. More complexity can push that out a week or two. Either way, they are in place before year-end. |
| Early to mid-November | New team takes over around December 1. Thanksgiving slows the onboarding, but the team is in place for year-end. |
| December 1 or later | The worst case. Onboarding runs through the holidays, when your own team is hardest to reach. Expect a rushed December or a takeover that slips into the new year. |
Example: a business around $3M in revenue.
Starting in October also takes the pressure off the decision. You have time to talk to two or three firms and pick the right one. A mid-December start forces you to take whoever can start fastest.
Why do the holidays slow down a transition?
Because the pace is set by your team, not the firms. A new accounting team needs access, documents and answers from you and your staff. Around Thanksgiving and Christmas, the people who can provide them are out, busy or closing their own year.
Most of the delay we see in November and December comes from waiting on the business, not from the work itself. Owners who move fastest name one person on their team to own the handoff and answer questions within a day or two.
Who hands over the accounting system?
You do. Your previous accountant isn't really part of the handoff. You add your new team as users in your accounting system. On the date you agree on, you remove the previous accountant.
That only works if you hold the admin role, so check it now. In QuickBooks Online, an accountant who holds the primary admin role can transfer it back to you. In Xero, the subscriber controls the subscription, so confirm whose name is on it.
Don't count on receiving bank reconciliations, workpapers, schedules or written procedures from the previous accountant. They rarely come. A good new team expects to build all of that during onboarding, which is part of why onboarding takes weeks, not days. It is also why you shouldn't put off a switch while you wait on the old provider.
How does the handoff work between the old and new accountant?
There are two ways it goes: a planned cutover or a fast takeover.
Planned cutover. This is the better option. The previous accountant finishes a month-end close and stops. The new team starts on the 1st of the next month. Everyone knows who owns which month, and nothing falls between the two teams.
Fast takeover. Sometimes there is no planning, and the new team has to jump right in. In that case the new team takes care of what can't break first:
Payroll, so your people get paid on time.
Bill payments, so vendors get paid and nothing goes past due.
Sales invoicing, if the new team is taking it on, so cash keeps coming in.
Reconciliations, reporting and cleanup follow once those are stable. Starting early is how you get a planned cutover instead.
What will the new team need from me?
Most of what a new team needs comes from you, not your old provider. Have these ready and onboarding moves faster:
User invites to your accounting system for your new team, sent by you as the admin. Never share passwords.
Bank and credit card access or statements for every account the business uses.
Payroll access, plus a list of every app connected to your books, such as payments, expense tools and your CRM.
Last year's tax return and your tax accountant's contact information.
Loan, lease and major contract documents.
Vendor W-9s, if you have them. Form 1099-NEC is due to contractors and the IRS by January 31, so a team in place by December can prepare 1099s on time. Our post on the new $2,000 1099 threshold covers what changed for 2026.
One point person on your team who can answer questions quickly.
Is it better to switch before year-end or after?
Before. Switching before year-end means you start the new year fresh, with the new team already running your books. You aren't scrambling to change providers the week you get back from the holidays. You also get a full year of better data, from January on, instead of a year split between two teams.
If you are already into December, don't wait for a "clean" start date. Sign, start onboarding and accept that January will be a transition month. It still beats running another year on books you don't trust. If you are still deciding whether it is time at all, start with our post on the signs it's time for a new accounting team.
Why does team structure matter in a transition?
A transition depends on more than one person. At Basis 365, every customer gets the same four-role team: Bookkeeper, Accountant, Accounting Manager and Controller, with the mix set to the business's needs. The work keeps moving when someone is out, which matters most in November and December. You can see how our outsourced accounting team works on our services page.
Frequently asked questions
How long does it take to switch accountants for a small business?
For a business under $1M in revenue, a couple of weeks is typical. A business around $3M takes about 3 weeks, and one closer to $10M takes 5 to 6 weeks. Major cleanup or a handoff of sales invoicing adds time.
Will my old accountant help with the transition?
Rarely in a meaningful way. You give the new team access to your accounting system, and they build everything else, including reconciliations and procedures. The most useful thing the old accountant can do is agree on a clean stopping point.
Should I tell my current accountant before I sign with a new firm?
Usually no. Sign first and make sure you hold the admin role in your accounting system. Then agree on a stop date with your current accountant, ideally right after a month-end close, and remove their access on that date. Check your engagement letter for a notice period.
Does handing off invoicing slow down the switch?
Yes. Sales invoicing is optional, but it is one of the more time-consuming workflows to transition. If you want it included, plan for more than a month and don't rush it into the holidays.
Do I have to change accounting software when I switch firms?
No. A good firm works in the system you have unless there is a real reason to move. If you are weighing a software change too, our post on switching from QuickBooks to Xero covers when it makes sense.
Want to know what a new team would find in your books? Our free Financial Operations Assessment takes a few minutes and shows where your accounting is solid and where it needs work.
Sources. Basis 365 onboarding process and experience onboarding new customers. IRS, Instructions for Forms 1099-MISC and 1099-NEC. Intuit, Transferring the QuickBooks Online primary admin role from an accountant. Xero, About the Xero subscriber.
This post is education, not tax advice. Talk to your tax accountant about filing deadlines and anything specific to your return.
