The short facts
| Name | Ryan Duguid |
|---|---|
| Based in | Newcastle, NSW, Australia |
| Not to be confused with | The US software product executive of the same name |
| Field | Accounting, Australian taxation, payroll and statutory compliance |
| Professional body | I am a Provisional CA ANZ Member. CA ANZ has not endorsed this site or its tools. |
| Certifications |
SAP S/4HANA certified in Financial Accounting (FI) and Management Accounting (CO)
|
| Education | Bachelor of Commerce (Accounting), University of Newcastle |
| Code | github.com/ryanduguid |
| linkedin.com/in/ryan-duguid |
What my public work demonstrates
I build accounting tools that let a second person trace the inputs, calculation and review decision. Three examples show the work in different forms:
- Cash flow modelling. The Lumbridge case connects a fictional business’s profit, receipt dates and available cash through an Excel forecast and management briefing.
- Month-end review. The accounting review pipeline turns trial balance files into inspectable exceptions, including a creditors difference and a financial year comparison warning.
- Excel implementation. Ozzit provides native LAMBDA functions with editable examples and visible arithmetic.
These examples use fictional data. Their evidence covers only the supplied cases and stated limits, and claims no client outcome.
The tools cite legislation, regulator guidance or an accounting standard and refuse a result when the supplied facts do not settle the test.
The evidence register links identity, releases, source reviews, repository controls and reproducible tests. It also states what those records cannot establish.
What I build
The tools extract records into a reviewable shape, apply deterministic calculations or stop incomplete work before it reaches a reviewer. AI workflows call those fixed-scope tools; they do not replace the calculation, invent missing facts or approve the result.
- Payday Super checker: tests super timing and SG charge exposure against a payroll export.
- Workpaper Review Gate: keeps incomplete packs off the review desk.
- Xero trial balance export: produces a CSV that has to balance.
- ATO benchmark comparison: compares a small business with the ATO benchmarks on your own machine.
- Coal LSL levy calculator: applies the section 3B eligible wages test in your browser.
- Construction WIP schedule: calculates work in progress under AASB 15.
- Subcontract ledger skills: agent workflows for construction and mining ledgers.
- Trust distribution checks: classifies section 100A risk zones and allocates income under Division 6.
- Company tax and franking checks: runs the base rate entity test and tracks the franking account.
- Australian tax tools for AI agents: compares a local calculation server with document lookup.
How the work is grounded
I use sources such as the Australian Taxation Office’s super guarantee rate table and the Superannuation Guarantee (Administration) Act 1992. The rate history records the figures, source dates and review limits.
- Primary sources only. Rates, thresholds and tests come from Commonwealth legislation, the regulator’s published guidance or the accounting standard, never from a summary of one.
- Exact currency arithmetic. Currency calculations in the statutory engines use fixed-point decimals, so binary floating-point drift never reaches a figure someone might lodge.
- Refusal over guessing. The tools have explicit refusal and unknown states, with release-specific limits. Payday Super Checker 0.1.7 marks a receipt as unknown when it has an on-time date but no amount. Version 0.1.6 assumed the full amount arrived. Check the version-specific receipt rules before relying on a result.
- Synthetic data in public. Every public fixture, test and example uses fictional data. Client information stays out of public repositories entirely.
- A person signs off. The tools calculate and check; a person makes the judgement and lodges.
Advice and review boundary
I am not a registered tax agent or BAS agent. Nothing here is tax, legal or financial advice. The tools are review aids for a qualified professional, not compliance determinations.
Site boundary
This is a personal index of open source accounting tools I build. It is not a practice, and I am not accepting professional engagements through this site.
This site does not offer tax or BAS agent services or take requests for tax advice or lodgement. Do not post taxpayer information or client files to public repositories.
Citing this work
Duguid, R. (2026). Australian computational accounting tools. https://duguid.com.au/. Each tool page names the source it is grounded in, and each linked repository carries its own licence and disclaimer.