A Tradie's Guide to Calculating and Managing Project Variations
9 September 2026 · 6 min read · By Heaney Accounting
What counts as a variation?
A variation is any change to the original scope of work after the contract has been signed. Whether it is a client asking for extra power points, or hitting rock during an excavation, these changes cost you time and money.
- Document the request in writing immediately.
- Calculate the extra labour and material costs.
- Add your standard profit margin to the variation cost.
- Get the client to sign off on the variation price before doing the work.
- Update your invoice to show the original contract plus the approved variation.
Pro Tip: Never start work on a variation until you have a signature. A verbal 'go ahead' often leads to disputes when the final invoice arrives.
Avoid 'scope creep'
- Doing 'small favours' without charging.
- Not accounting for the extra time spent travelling back and forth.
- Forgetting to include the cost of rubbish removal for extra waste.
- Not adjusting the final completion date for the extra work.
By treating every change as a formal variation, you protect your cash flow and ensure the business is paid fairly for every minute spent on site.
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