DB in WPS Spreadsheet: Fixed Declining Balance and Rate Rounding
Build an independently checked fixed-declining-balance schedule with DB, understand its three-decimal rate and distinguish period depreciation from cumulative depreciation.
Verification status: See the evidence and test scope described in this guide. How formula examples are checked
DB calculates an individual period’s depreciation using a fixed declining-balance rate. The rate stays fixed, while the amount to which it applies falls as depreciation accumulates. This differs from charging the same monetary amount each year.
The WPS lesson specifies a rate derived from cost, salvage and life, rounded to three decimal places. It gives separate first-period and final-partial-period formulas. The original schedule below uses a full twelve-month first year and an exactly 0.5 rate, avoiding ambiguous rounding ties and partial-terminal indexing. Official DB lesson
Syntax and units
=DB(cost, salvage, life, period, [month])
The lesson prints all five names in its syntax line but explicitly says that omitted month means 12. Cost is the original value; salvage is the intended end value; life is the depreciation term; period identifies the period to calculate. Period and life must use consistent units. Month describes months in the first year, not the current period number.
For ordinary full periods, the lesson’s model is:
rate = 1 − (salvage/cost)^(1/life), rounded to 3 decimals
period depreciation = opening book value × rate
opening book value = cost − earlier depreciation
These formulas describe the spreadsheet calculation, not tax or accounting compliance. Choose a method and parameters appropriate to the actual reporting requirements separately.
Worked full-year schedule
Enter these fictional inputs:
| Cell | Meaning | Value |
|---|---|---|
| B2 | Cost | 1600 |
| B3 | Salvage | 100 |
| B4 | Life in years | 4 |
| B5 | First-year months | 12 |
Since 100/1600=1/16 and its fourth root is 1/2, the rate is 1−1/2=0.5 exactly. Enter period numbers 1–4 in A8:A11, and in B8 enter:
=DB($B$2,$B$3,$B$4,A8,$B$5)
Fill down. The independently calculated schedule is:
| Period | Opening value | Depreciation | Closing value |
|---|---|---|---|
| 1 | 1600 | 800 | 800 |
| 2 | 800 | 400 | 400 |
| 3 | 400 | 200 | 200 |
| 4 | 200 | 100 | 100 |
Total depreciation is 1500, and 1600−1500=100 agrees with the chosen salvage. Each DB call returns one period’s amount; it does not return cumulative depreciation or the closing balance.
Independent controls
=DB(1600,100,4,1,12) gives the reference expectation 800; changing period to 2, 3 or 4 gives 400, 200 or 100. Omitting the final argument in =DB(1600,100,4,1) uses the documented twelve-month default and has the same expectation 800.
Scaling both cost and salvage by two leaves their ratio unchanged. Thus =DB(3200,200,4,2,12) has expectation 800, twice the second-period depreciation in the original schedule. This is a useful arithmetic cross-check of the rate-versus-amount distinction.
Why the rounded rate matters
A general asset need not produce an exact three-decimal rate. The lesson’s published asset has cost 1800000, salvage 200000 and life 6. Its rounded rate is 0.307. The displayed first-seven-month calculation is 1800000×0.307×7/12=322350, matching the published walkthrough.
That vendor observation corroborates the first-period scaling rule. It is not an execution of the original schedule above. Using the unrounded root throughout a new schedule would describe a different calculation from the stated rounded-rate method, and a general schedule should not be promised to hit salvage exactly just because this carefully chosen example does.
Partial years and troubleshooting
The lesson specifies first-period depreciation as cost×rate×month/12 and a final partial-period expression involving(12−month)/12. Those are special cases. This guide’s original controls do not certify every fractional-year terminal period or out-of-life request, and the full-year table should not be relabeled as a partial-year schedule.
The reviewed page does not give a comprehensive error table. Use positive cost greater than positive salvage, a positive integer life, and valid integer periods within the intended term for this walkthrough. Zero salvage, negative inputs, fractional periods and exact error tokens need separate product evidence.
SLN uses a straight-line model. SUM can total period amounts, but keep that total distinct from any single DB result.
Availability and evidence scope
The official WPS lesson is dated 2019-06-11 and explicitly applies to WPS Office for Windows Personal. Its numeric build is unspecified. This is a documented-by date, not a function introduction date; the first supported version and last functioning build remain unknown. The lesson does not establish Linux or other-edition parity, nor a retirement or deprecation history.
The complete text and vendor walkthrough were inspected on October 18, 2026. The original examples in this guide are documentation-derived and independently calculated, not executed in WPS or another spreadsheet engine. Vendor walkthrough observations are identified separately and are not native tests of these examples.