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
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 15+ years 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.