In-house accountant vs outsourced accounting firm
Quick answer
An in-house accountant suits high daily transaction volume and a need for someone on site. A firm suits businesses that want continuity, layered review, and no exposure when a single hire resigns. Compare total cost — salary, social security, software, training, and the risk of a wrong filing — not the monthly wage alone.
Side-by-side facts
| Aspect | In-house accountant | Outsourced accounting firm |
|---|---|---|
| Visible cost | Salary, bonus, benefits | Monthly fee scaled to document volume |
| Hidden cost | Social security, software, training, workspace, and the gap while rehiring | One-off setup and back-work clean-up if the prior records are messy |
| Review layers | Often a single person with no second review | Reviewer and supervisor sign-off before filing |
| Continuity | Resignation stalls work and knowledge walks out | Team-based with documented handover, not dependent on one person |
| Specialist depth | Bounded by one person's experience | Access to tax, audit, and legal specialists in one team |
| Best fit | High daily volume with an existing internal system | SMEs wanting accuracy and continuity without headcount |
Choose In-house accountant when
- Hundreds of daily documents needing same-day entry
- A finance leader is present to supervise and review
- You need someone on site for inventory and stock work
Choose Outsourced accounting firm when
- You want continuity that survives resignations
- You want layered review before every filing
- You want tax and legal advice from the same team
- You are cleaning up back-work or have received a Revenue Department notice
Documents to prepare
- Financial statements and filed tax returns for the past 2–3 years
- Chart of accounts and a backup from the current software
- Fixed-asset register and depreciation schedule
- AR, AP, and inventory balances at handover date
- Employee list and social security base
Step by step
Durations are estimates from typical engagements and vary with documents, authority queues, and the facts of each case.
1. Health check
Review past statements and filings to find gaps or exposure before deciding the team structure.
Typical duration: 3–5 business days
2. Model both total costs
Put every hidden cost in one table and compare monthly and annually.
Typical duration: 1–2 business days
3. Plan the handover
Fix the cut-off date, owners, and the handover list.
Typical duration: 1 week
4. Set up and close month one
Configure the chart of accounts and document cycle, then close month one with a management report.
Typical duration: 30 days
What usually goes wrong
- Comparing wages only, ignoring social security, software, and rehiring gaps.
- Switching mid-year without a clean cut-off, leaving opening balances wrong.
- Not securing a backup from the old software and re-keying an entire year.
- Letting one person record, approve, and pay — the classic fraud gap.
Why an adviser beats a template
We do not just deliver statements. We show why gross margin moved, which documents blocked an input-VAT claim, and which process to fix. With extensive experience serving Thai SMEs and foreign-owned companies, we work as your financial advisor, not a data-entry vendor.
Frequently asked questions
Can I switch firms mid-year?
Yes. Set a clear cut-off and hand over the ledger files, asset register, and filed returns so opening balances reconcile and nothing is filed twice or missed.
Can I have both?
Yes, and it is common: internal staff handle daily documents while the firm handles closing, review, and tax — giving you two review layers.
How is the fee set?
Typically by monthly document volume, payroll headcount, business complexity, and any back-work. We quote a range only after reviewing your actual documents.
Official sources
Not sure which route fits your case?
Call +66-92-017-0000, email contact@tla.co.th, or message us on LINE. Monday to Saturday, 09:00–18:00 Bangkok time, in English or Thai.