Christmas Cash Gap Calculator

How the calculator works

The dates. Under the Building Industry Fairness (Security of Payment) Act 2017, the BIF Act, a business day is any day except a weekend, a Queensland public holiday or a day from 22 December to 10 January. Unless the contract says otherwise, a progress payment falls due 10 business days after the claim is given, and a claim given on a day that is not a business day counts as given on the next one. The calculator counts each due date that way, adds any business days your clients usually pay late, and takes off the retention they hold.

The money. Each pay run leaves on its pay day, with super either alongside it or 7 business days later. Supplier payments, the BAS and anything else you add leave on their dates. Money in is counted before money out on the same day.

The formula. Your balance at the end of each day equals the balance the day before, plus payments received that day, less payments made that day. Your lowest balance is the smallest of those daily figures. The cash or facility you need is your buffer less that lowest balance, or nothing when the balance never falls below your buffer.

Worked example

Illustrative, built from public rules and typical figures for a builder, and checked in code on 21 October 2026.

A builder starts Monday 14 December 2026 with $150,000 in the bank. Its claims include GST, its clients hold 5 per cent retention, the BIF Act default of 10 business days applies and clients pay on the due date. A $220,000 claim given on Monday 30 November falls due on Monday 14 December, and $209,000 arrives. A $260,000 claim given on Monday 21 December falls due on Friday 22 January 2027, because the break stops the clock, and $247,000 arrives then; its payment schedule is due by Monday 1 February, after the Australia Day holiday. A $280,000 claim given on Friday 29 January falls due on Friday 12 February, bringing $266,000.

Pay runs of $48,000 including super leave every Thursday from 17 December to 25 February, eleven in all, and five of them, $240,000, go out before the 21 December claim is paid. Suppliers take $120,000 on Thursday 31 December and $90,000 on Friday 29 January, and the October to December BAS of $65,000 is paid on Monday 1 March 2027.

The balance first falls below zero on Thursday 14 January, $1,000 overdrawn. The lowest point is $49,000 overdrawn on Thursday 21 January 2027, with a second low of $36,000 overdrawn on Thursday 11 February. The builder needs $49,000 of cash or facility to stay at zero, or $99,000 to keep a $50,000 buffer, and ends the window on 1 March with $69,000.

Why January bites. A claim given on Monday 7 December 2026 still falls due on Monday 21 December on the default terms. One given a day later, on Tuesday 8 December, falls due on Monday 11 January 2027, while wages and super keep going out every week of the break.

How to read your result

Your balance stays above your buffer throughout. On these figures the claims land in time. Try the 7 day late payer to see how much room you have when a client is slow.

Your balance falls below your buffer on a date. You stay in credit but dip into the cushion you set. The cash needed is what it takes to keep the buffer whole.

Your balance goes below zero on a date. Without a facility the account would be overdrawn from that day. The cash needed is the cash or overdraft to have in place before the break.

Questions owners ask

What counts as a business day?

Under the BIF Act, every day except a Saturday, a Sunday, a Queensland public holiday and the days from 22 December to 10 January. Payment claim, payment schedule and adjudication clocks all stop over that break.

What happens to a claim given on 23 December?

It counts as given on the first business day after the break, Monday 11 January 2027 by our count, so on the default terms it falls due 10 business days later, on Monday 25 January 2027.

Does paid leave keep payroll running?

Yes. Staff on accrued paid leave are paid as usual over a shutdown, so wages and super keep leaving your account while claims wait. The award lets you direct staff to take accrued paid leave with two months' written notice, or a shorter period agreed with most of the affected staff. You cannot direct unpaid leave.

Why does the BAS sit in the window?

The October to December BAS is due on 28 February 2027, a Sunday, so lodgment and payment move to Monday 1 March. On the accruals basis it carries the GST on every claim you issued in the quarter, December's included, and it falls due just as the January claims are paid. The window runs to 1 March so the BAS falls inside it.

Rules this tool uses

• 22 December to 10 January. No business days count from 22 December to 10 January under the BIF Act. On the default terms a progress payment is due 10 business days after the claim, so by our count a claim given on Monday 21 December 2026 is due on Friday 22 January 2027, while wages and super keep going out. Source: QBCC, in force from 28 April 2026, checked 20 October 2026.
• Payday Super, from 1 July 2026. Since 1 July 2026, super guarantee contributions must reach each employee's fund within 7 business days after each payday, with some exceptions such as a new employee. The guarantee is 12 per cent of ordinary time earnings. Source: ATO, in force from 1 July 2026, checked 20 October 2026.
• 28 February 2027. The October to December BAS is due on 28 February 2027, a Sunday, so lodgment and payment move to Monday 1 March. On the accruals basis it carries the GST on every claim issued in the quarter, December's included. Source: ATO, checked 20 October 2026.
• Two months before a shutdown. The building, electrical and plumbing awards require two months' written notice of a Christmas shutdown, or a shorter period agreed with most of the affected staff, and allow a written direction to take accrued paid leave during it. You cannot direct unpaid leave. Source: Fair Work Commission award MA000020, clause 31.3, in force from 1 May 2023, checked 20 October 2026.
• Queensland public holidays in the window. Christmas Day on Friday 25 December 2026, Boxing Day on Saturday 26 December with an additional public holiday on Monday 28 December, New Year's Day on Friday 1 January 2027 and Australia Day on Tuesday 26 January 2027. Source: Queensland Government, Public holidays, checked 21 October 2026.

Last reviewed 21 October 2026.