The 5-line profit check every trade business should run monthly.

Five numbers, five minutes. Run them at the end of each month and you'll spot a job quietly losing money long before it shows up in your bank balance.

• The exact five lines to pull from Xero, MYOB or QBO — no accounting degree needed.
• The one ratio that tells you if a job actually made money, or just looked busy.
• What "healthy" looks like for a trade business — so you know when to worry.