Fixed asset depreciation under Circular 45 on NetSuite: daily proration, adjusted declining balance and useful-life ranges
Written by the S4 Consulting Oracle NetSuite team · Reviewed by Lạc Phạm, Solution Architect, S4 Consulting · Updated 27 Oct 2026
Fixed asset depreciation under Circular 45 on NetSuite depends on three rules that the standard NetSuite Fixed Assets Management SuiteApp (standard FAM) does not cover out of the box: proration by the actual number of days in the month of acquisition or disposal, the adjusted declining balance method with coefficients of 1.5, 2.0 and 2.5, and the minimum and maximum useful lives in Appendix I. Standard FAM offers Pro-rata and Mid-month conventions and lets you build formulas, yet its period logic follows US practice, so odd months rarely match the accountant’s spreadsheet. S4 eSuite FAM for NetSuite brings these Vietnamese rules into NetSuite and previews every charge before posting.
How does fixed asset depreciation under Circular 45 differ from international practice?
The main difference is that Circular 45/2013/TT-BTC prescribes the rules, while international standards leave conventions to management judgment. A Vietnamese accountant cannot pick a convenient period convention or an arbitrary useful life. The key rules are:
- Daily proration: depreciation starts or stops on the day the asset is added or retired, measured against the actual number of days in that month, with no rounding to whole or half months.
- Permitted methods: straight line, adjusted declining balance, and units of production, each with its own eligibility conditions.
- Useful-life ranges: every asset group in Appendix I has a minimum and a maximum life, and the company chooses a value inside that range.
- Limited changes: the depreciation period may be changed only once, and the method must be applied consistently.
- Recognition threshold: a tangible fixed asset needs a cost of at least VND 30 million and a useful life of more than one year; anything below is tracked as tools and supplies.
Accountants coming from local packages such as MISA, FAST or Bravo treat these rules as defaults because those systems were built around them. On a global ERP like Oracle NetSuite, the same defaults become configuration work that has to be tested and reconciled, since one wrong convention multiplies across hundreds of asset cards.
How is depreciation prorated by actual days in the month of acquisition?
The charge for the first month equals the full monthly charge multiplied by the days in use divided by the total days of that month. Illustrative example: a packing machine costs VND 120,000,000 and is depreciated straight line over 5 years, so the full monthly charge is VND 2,000,000. It goes into service on 15 October; October has 31 days, so 17 days count (15 to 31 October).
| Approach | Days counted in October | Formula | October charge (VND) |
|---|---|---|---|
| Actual days (Circular 45) | 17/31 | 2,000,000 x 17 / 31 | 1,096,774 |
| 30-day month convention | 16/30 | 2,000,000 x 16 / 30 | 1,066,667 |
| Mid-month convention | Full month or none, depending on whether the start date falls in the first or second half | No daily proration | 2,000,000 or 0 |
The gap between Circular 45 and a 30-day convention is VND 30,107 for one asset in its first month. It does not disappear: total depreciation still equals cost, so the difference rolls into the final month and the system schedule drifts away from the schedule the accountant keeps. Disposal months work the same way, with depreciation stopping from the day the asset leaves the books.
Circular 45 depreciation, right inside NetSuite
Preview actual-day charges, adjusted declining balance and the tax-deductible portion before you post.
What does standard NetSuite FAM do with partial months, and why do gaps remain?
Standard FAM is a capable product. According to Oracle NetSuite Help, each asset type carries Acquisition, Disposal, Pro-rata and Mid-month depreciation rules; depreciation methods can be defined by formula; Revision Rules (Current Period or Remaining Life) handle value changes; usage-based depreciation is available; and Alternate Methods support a separate tax depreciation book.
The gap is in the conventions. FAM Pro-rata assumes a 30-day month and Mid-month uses a half-month cut-off, whereas Circular 45 counts the real 28, 29, 30 or 31 days. The adjusted declining balance method with Circular 45 coefficients and its switch to straight line must be built as a custom formula and tested. Standard FAM also has no Appendix I asset groups to validate useful lives, and no counter for how many times a period has changed. This is a design choice rather than a defect: FAM was written for US practice, where companies set their own conventions.
How does adjusted declining balance work with coefficients 1.5, 2.0 and 2.5?
The annual charge equals the opening net book value multiplied by an accelerated rate, which is the straight-line rate times a coefficient: 1.5 for lives up to 4 years, 2.0 for more than 4 and up to 6 years, and 2.5 for more than 6 years. Once that charge is equal to or lower than the remaining value divided by the remaining years, the company switches to equal amounts for the rest of the life.
Illustrative example: new measuring equipment costs VND 600,000,000 with a 5-year life, a straight-line rate of 20% and a coefficient of 2.0, giving an accelerated rate of 40%.
| Year | Opening net book value | Calculation | Annual charge | Monthly |
|---|---|---|---|---|
| 1 | 600,000,000 | 600,000,000 x 40% | 240,000,000 | 20,000,000 |
| 2 | 360,000,000 | 360,000,000 x 40% | 144,000,000 | 12,000,000 |
| 3 | 216,000,000 | 216,000,000 x 40% | 86,400,000 | 7,200,000 |
| 4 | 129,600,000 | 129,600,000 / 2 years | 64,800,000 | 5,400,000 |
| 5 | 64,800,000 | 129,600,000 / 2 years | 64,800,000 | 5,400,000 |
In year 3 the declining balance figure (86.4 million) is still above 216 million divided by 3 years (72 million). In year 4 it falls to 51.84 million, below 64.8 million, so the switch happens. The five years add up to exactly VND 600 million. The method is only available for certain new assets that meet the conditions in Circular 45.
How should Appendix I ranges and the one-time change rule be controlled?
The safest control sits at card creation, not at audit time. Each asset card should belong to an Appendix I group, and the system should block or warn when the chosen life falls outside the group range, because depreciation above the permitted rate is not deductible for corporate income tax.
The one-time change rule also needs a trail on each card: whether the period has changed, when, and on what basis. The Ministry of Finance is consulting on a draft circular to replace Circular 45 that points toward post-audit control; see what to prepare for the replacement of Circular 45. Whatever the final text says, a change history on the card remains essential evidence.
How does S4 eSuite FAM handle Circular 45 depreciation on NetSuite?
S4 eSuite FAM makes the Circular 45 rules the default behavior of the module, posting to the NetSuite general ledger. The features accountants use every month include:
- Full preview before posting: days counted, charge, the tax-deductible portion and the allocation by VAS account appear before any journal is created.
- Three methods: straight line, adjusted declining balance (1.5, 2.0, 2.5 with automatic switch to straight line) and units of production entered monthly.
- Range checks and change counter: Appendix I groups carry minimum and maximum lives; changes to life or method are validated and the card records how many times it has changed.
- Real-world events: suspend depreciation for idle assets or long repairs, catch up when an addition is booked late, and reverse a run to redo it.
- Multi-department allocation: one asset split across accounts 627, 641 and 642 by effective-dated ratios; assets funded by the welfare fund reduce the fund instead of hitting expense.
- Daily schedule: days counted, charge, posted amount, deductible portion, accumulated depreciation and net book value per month, exportable to Excel, plus the 06-TSCĐ depreciation allocation table.
The module shares master data and ledger with the S4 NetSuite financial localization for Vietnam. Retail and restaurant groups may also read about daily depreciation for restaurant and central kitchen equipment, and contractors about construction equipment depreciation and transfers. Full functional details are on the S4 eSuite FAM product page.
What should accountants check before the first depreciation run on NetSuite?
Before the first period, reconcile converted data against the old books with a fixed checklist rather than spot checks:
- Opening balances: cost, accumulated depreciation and net book value by account 211x and 214x match the ledger at the cut-over date.
- Remaining life: every card carries the correct remaining period, inside its Appendix I range.
- Start dates: assets added mid-month carry the in-service date from the source document so day counts are right.
- Allocation accounts: department ratios and expense accounts are complete and add up to one.
- Trial month: compare the preview with the current spreadsheet and explain every difference.
If you would like a review of your asset data before cut-over, contact the S4 Consulting team.
Video
See S4 eSuite FAM running on Oracle NetSuite
Circular 45 depreciation by days in use, Circular 99 registers and notes, QR counts and asset-to-GL reconciliation. Learn about S4 eSuite FAM
Frequently asked questions
How does Circular 45 prorate depreciation in the month of acquisition?
The monthly charge is multiplied by the days in use divided by the total days of that month. An asset added on 15 October is charged for 17/31 of a month.
Does standard NetSuite FAM depreciate by day?
Standard FAM has a Pro-rata rule based on 30-day months and a Mid-month rule, so partial-month charges can differ from the actual-day method required by Circular 45.
What coefficients apply to adjusted declining balance in Vietnam?
The coefficient is 1.5 for lives up to 4 years, 2.0 for more than 4 and up to 6 years, and 2.5 for more than 6 years.
How many times can the depreciation period be changed under Circular 45?
Only once. S4 eSuite FAM records the number of changes on each asset card.
Does S4 eSuite FAM replace the NetSuite general ledger?
No. S4 eSuite FAM runs inside NetSuite and posts journals to the NetSuite ledger using the Vietnamese chart of accounts.
