One Excel workbook holding 137 native LAMBDA functions and 5 named help tables under
the oz. prefix: amortisation, depreciation, ratios, AASB 16 lessee schedules, and
Australian GST and financial-year helpers. The functions need no add-in, macro, VBA or
external dependency, so a copied function travels inside your own file and a reviewer
can read the arithmetic. The file carries a hidden reference to the Advanced Formula
Environment task pane used to author the functions; the functions do not depend on
it. It suits an accountant or analyst modelling in Excel; it is not a
bookkeeping tool and never touches a ledger.
Needs Microsoft 365 or Excel 2024 or later, which support LAMBDA and dynamic
arrays. LibreOffice, Google Sheets and earlier Excel versions cannot evaluate the
functions. MIT licensed.
Current published release: v3.4.2,
published 20 September 2026 from the cut dated 16 September 2026.
Download ozzit.xlsx
(439,097 bytes, SHA-256 0306793a7e473ce70e78149fea1e107fc0f714d61ab50960c16f6fd528878f6f).
Known issues in v3.4.2. One blank cell in a column of GST rates gives every row
10%, zero-rated rows included; one blank opening in oz.Movementλ sets every row's
opening to 0; and negative CFADS raises the balance in oz.DebtSculptFixedλ and
oz.DebtSculptVariableλ. One blank cell likewise gives every row the default in a
column of PeriodsPerYear for oz.PeriodRateλ and oz.AnnualRateλ, of Unit for
oz.DateDifλ and of Repeats for oz.IsOccurrenceDateλ, whose LastOccurrence column
reads no text date once another row holds a date or a blank. In v3.4.2, fill every such
cell and enter last occurrences as dates. All of these are fixed on main for the next
release. Further changes and the DB/DDB compatibility limitations are recorded
under Unreleased in the changelog.
Synthetic example. Review aid, not professional advice; the reviewer decides the GST treatment.
Input: $1,100, assumed wholly taxable and GST-inclusive at 10%.
=oz.GSTExtractλ(1100)
Output: the cell displays $100.00 GST under currency formatting, reproduced in
Excel 16.0 build 20430 against the exact v3.4.2 release on 25 September 2026.
Inputs, raw results and unchanged workbook hash.
The function returns the unrounded binary-float result,
99.999999999999986, so a caller who needs cent-exact totals wraps it in
ROUND(...,2). The hand calculation is $1,100 / 11.
Human decision: Does the evidence establish that the whole supply is taxable?
Browse ten worked formulas, including arguments, expected results and limits for v3.4.2.
Historical v3.2.0 screenshot
Captured in Microsoft 365 using Ozzit v3.2.0, Australian tax!A19:B19; the reviewer still decides whether the supply is taxable.
This earlier image is retained as historical evidence. The current numerical check above used a different workbook file.
You do not need all 137 functions. Most models start with one of these three. The loan and depreciation guides show the spilled result for a synthetic input you can check by hand; the lease guide explains the four lessee functions.
| Task | Formula | Guide |
|---|---|---|
| Loan schedule | =oz.Amortiseλ(Principals, APRs, Terms, StartDates) |
100,000 at 5% over 60 months |
| Depreciation | =oz.DiminishingValueλ(Cost, Life) |
1,000 over 5 years |
| AASB 16 lease | =oz.LeaseScheduleλ(Payments, Rate, [InAdvance]) for the liability, =oz.ROUScheduleλ(Cost, Periods) for the right-of-use asset |
Lessee functions and rate conversion |
Open, copy functions and use modern Excel shows how to copy a function into your own workbook.
Setup, function catalogue, workbook examples and reference
A library of 137 native Excel LAMBDA functions plus 5 named help tables for dynamic-array financial models, with inline help and editable demonstration worksheets under the oz. prefix. LibreOffice and older Excel versions cannot evaluate the functions.
The 6 September 2026 capture used Excel 16.0 build 20326. The released workbook opened without a repair prompt and a full calculation rebuild returned numeric 100 for the displayed formula.
v3.2.0 release asset SHA-256: 13df5eb0e2e7a3d1b17a743a990c30adfd187d409be133996ec154543e78ff28.
The capture record and PowerShell reproduction preserve the Excel command, returned value, crop and image fingerprint.
The screenshot uses a disposable copy with a synthetic label, an explicit argument in B19 and currency formatting. It certifies this example in v3.2.0. The v3.4.2 workbook is a different file; its full native gate results are recorded in its release notes and in CHANGELOG.md. The shipped workbook was not edited.
- Open, copy functions and use modern Excel
- Modules, worksheets and formula walkthroughs
- Australian conventions and lease modelling
- Separate 13-week cash-flow template
- Comparing a modelling schedule with an accounting carrying amount
- Ratio definitions: the arithmetic, periods and balances each ratio expects
- Modelling conventions: where Ozzit follows or departs from the FAST Standard and the ICAEW Financial Modelling Code
- Function index, source views and the whole library as one Advanced Formula Environment module, oz.txt
The current release is v3.4.2, dated 16 September 2026; citation metadata is in CITATION.cff. It was published on 20 September 2026 from the signed tag v3.4.2 on commit 621af0e265306f00a83e17c4d27dca09031c5ccd, after the native gates RELEASING.md requires ran on the exact file it ships. The release page carries ozzit.xlsx, provenance.json and SHA256SUMS, and GitHub reports the release immutable.
v3.4.2 ozzit.xlsx SHA-256: 0306793a7e473ce70e78149fea1e107fc0f714d61ab50960c16f6fd528878f6f (439,097 bytes), the same bytes as the release asset. main is ahead of that tag, so the file you clone is not the file the release ships: the tracked ozzit.xlsx is SHA-256 8c42e2278de61bdacfb090b940e684bb12a7636a256816aa20f81360b71bb760 (452,439 bytes), pinned in release/workbook-base.json and checked by the tool tests. On 29 September 2026, Excel 16.0 build 20430 recalculated 1,129 formulas with 0 in error, ran 1,033 self-test assertions with 0 failures and found 19,446 cached values equal to what their formulas produce. The workbook was byte-identical before and after both native gates.
MIT licensed. See LICENCE. DISCLAIMER.md states that this is not advice and names the bodies the project is not affiliated with.