Construction month-end turns on the WIP schedule. The formula is easy. Applying it the same way every month is the work: strip waste from percentage complete without dropping it from margin, book uninstalled materials at cost, constrain unapproved claims and present each contract as an asset or a liability, never a portfolio net.
This tool does the arithmetic. Install the Python engine, point it at a contract CSV and keep the schedule beside the review pack. Recognition over time versus at a point in time, contract combination, claim enforceability and any onerous-contract provision stay with a person. The subcontractor ledger skills own that workflow: they assemble the file and name this engine rather than inventing the numbers.
What this tool does
- Measures cost-to-cost progress after AASB 15 para B19 exclusions: waste does not accelerate percentage complete; uninstalled materials are recognised at cost with zero margin. Whether uninstalled materials qualify for that treatment depends on the applicable paragraph B19 conditions, so check them against the contract before relying on it; the fixed example below contains none.
- Constrains unapproved variation estimates by the include ratio you supply, flags the excluded slice and never treats an uncertified claim as billing or entitlement.
- Classifies each contract as a contract asset or a contract liability, flags profit fade of 1.00 percentage point or more, and flags a stale estimate to complete after material extra spend.
Worked example: a $50,000 contract asset
This synthetic example comes from the cost-to-cost underbilling test in the-wip-tally v0.1.2. The test uses a reasonably measurable outcome, with no variations, waste or uninstalled materials. All amounts below exclude GST.
- Transaction price: $1,000,000.
- Costs incurred: $400,000. Estimated cost to complete: $400,000.
- Certified billings: $450,000.
Progress is $400,000 ÷ ($400,000 + $400,000) = 50%. Revenue to date is 50% × $1,000,000 = $500,000. Deducting $450,000 of certified billings leaves a $50,000 contract asset and no contract liability.
A person must confirm that the recognition basis, contract terms and estimates support this calculation. The test’s conditional retention does not change this revenue-minus-billings result; retention classification and final sign-off still need review.
Reproduce this exact example
In a fresh folder, with Git and uv installed, run the test at the release used above:
git clone https://github.com/ryanduguid/australian-accounting.git
cd australian-accounting
git checkout the-wip-tally/v0.1.2
cd packages/the-wip-tally
uv run --locked --extra dev --python 3.12 pytest -q tests/test_schedule.py::test_clean_cost_to_cost_underbillingExpected: one passing test and exit 0. The test asserts the figures above. The broader sample under Get it contains different inputs. The test is pinned to the-wip-tally/v0.1.2 so its figures stay reproducible.
Limits
This is an educational tool, not tax, legal or financial advice, and using it creates no professional relationship. Outputs are not an accounting opinion, an audit conclusion or an AASB 15 determination. Confirm the operative compilation at standards.aasb.gov.au before citing a paragraph number, and leave sign-off with a registered practitioner.
Get it
Needs Python 3.11 or later. A command-line tool for whoever runs Python at your firm.
git clone https://github.com/ryanduguid/australian-accounting.git
cd australian-accounting/packages/the-wip-tally && pip install .
wip-tally schedule examples/sample_contracts.csv --as-at 2026-08-31The sample raises review flags by design. Exit code 2 means a person needs to look; it is not a crash. Then:
wip-tally review-pack wip-schedule.csv --source examples/sample_contracts.csv -o practitioner-review.mdSource on GitHub · Use it from the subcontractor workflows
Software issue using fictional data? Open an issue or email with the tool named in the subject. If the email link does not open, the contact page spells the address out.
Common questions
What is a contract asset versus a contract liability?
Revenue to date less certified billings, per contract. Positive is a contract asset. Negative is a contract liability. The engine never offsets one job against another.
Does wasted cost accelerate percentage complete?
No. Para B19(a) amounts are stripped from the progress measure and kept in estimated cost at completion, so they hit margin instead of pulling revenue forward.
Are unapproved variations booked in full?
No. Only the constrained slice (unapproved estimate multiplied by the include ratio) enters transaction price. A bare 25 is refused; use 0.25 or 25%.
Is this an accounting determination?
No. It is a review aid. Recognition over time versus at a point in time, whether a claim is enforceable and any AASB 137 onerous provision stay with the engagement lead.