What the MIRA input tax statement asks for
Seven columns per invoice, and what MIRA does with each one. Why a missing supplier TIN costs you the claim.
The input tax statement is a list. One line per supplier invoice, seven things about each one. That is the whole document — the difficulty is never the form, it is having the seven things for every invoice in a box of paper that has been accumulating for three months.
Here is what each column is for, and which ones will cost you the claim if you get them wrong.
The columns
- Supplier NameWho you bought from
- As printed on the invoice. If a supplier trades under one name and is registered under another, the registered one is the safer choice.
- Supplier TINTheir tax number
- The field that carries the whole claim. MIRA matches your input against the supplier's declared output, and a TIN that is missing or wrong is a line that cannot be matched.
- Supplier Invoice NumberTheir reference, not yours
- The number the supplier printed. Substituting your own purchase order number breaks the match at the other end.
- Invoice DateWhen it was issued
- The date on the invoice, not the date you paid it or the date you photographed it. This is what decides the period the claim falls in.
- Invoice Total (excluding GST)The amount before tax
- The taxable value. Not the amount you paid, unless the invoice happened to carry no GST at all.
- Invoice Total (including GST)The amount you paid
- Before-tax plus the GST charged. The two totals and the GST column have to agree with each other.
- GST Charged at 8% / 16%The tax itself
- The claim. It goes in the column for the rate the supplier charged — which is theirs, not yours. There are columns for 6% and 12% as well, for periods before January 2023.
One invoice, one line
An invoice for 9,450.00 before tax with 8% GST on it becomes this, and nothing else:
| Supplier TIN | Invoice no. | Date | Excl. GST | Incl. GST | GST at 8% |
|---|---|---|---|---|---|
| 1234567GST123 | 4471 | 06/04/2026 | 9,450.00 | 10,206.00 | 756.00 |
10,206.00 is 9,450.00 plus 756.00, and 756.00 is exactly 8% of 9,450.00. If those three do not reconcile on a line, that line is the one that comes back.
Where claims actually go wrong
- A missing supplier TIN. The single most expensive omission. Without it there is nothing to match your claim against, and small suppliers are the ones most likely to leave it off an invoice. Ask before you file, not after.
- The wrong rate column. The rate is the one the supplier charged, not the one you charge your own customers. A guesthouse buying paint from a hardware shop claims in the 8% column.
- A date read backwards. 04/12/2026 is 4 December or 12 April depending on who wrote it. Get it wrong and the claim lands in the wrong quarter — a claim in the wrong period is not a claim.
- The same invoice entered twice. Easy to do when a supplier sends a statement as well as an invoice, or when a number is mistyped so the duplicate does not look like one.
- Totals that do not add up. Usually a transcription slip. It is also the easiest thing for anyone checking to spot.
Filling it in
By hand, this is a spreadsheet and a stack of paper, and it takes the time it takes. The tedium is not the typing — it is that every line needs a number read off a photograph, and one wrong digit is a correction later.
That is the job Tax Flow does: photograph the invoices and it produces this file, flagging the lines where it was not certain rather than filling them in confidently and wrongly.