Should I charge fixed price or do and charge for an unfamiliar job?

Charge fixed price only if the scope of work is fully defined and exclusions are documented in writing. For highly uncertain tasks, a do-and-charge hourly rate is safer. Alternatively, implement a hybrid quote: fix the price for predictable preparation work, then bill the complex or unfamiliar installation as do-and-charge.

How do I calculate an Australian tradie hourly charge-out rate?

Calculate your charge-out rate by dividing annual overheads, superannuation, vehicle running costs, insurances, and target net profit by billable hours. Most Australian sole traders only achieve 1,200 to 1,500 billable hours per year after deducting travel, administrative quoting, tool maintenance, public holidays, annual leave, and inclement weather downtime.

How much contingency should I add to an unfamiliar trade quote?

Add a 15% to 25% contingency buffer to labour and materials on an unfamiliar trade quote. This margin covers learning curves, unexpected site access restrictions, and minor material shortfalls. Ensure the contract includes explicit variation clauses stating that concealed structural defects, poor ground conditions, or non-compliant pre-existing work will incur additional costs.

How do I estimate material quantities for a job I have not done before?

Measure the site dimensions accurately and apply an industry-standard waste factor of 10% to 15%. Refer directly to manufacturer technical data sheets from Australian suppliers such as Bowens, Bunnings Trade, or Reece to confirm spread rates, fastener spacings, and fixings that comply with the National Construction Code.

What exclusions should I include when quoting an unfamiliar job?

Explicitly exclude council planning approvals, structural engineering certificates, asbestos removal, underground service diversions, and rectification of non-compliant existing services. State in your quote conditions that the pricing assumes continuous site access during standard working hours and that unforeseen sub-surface obstacles or rotten structural timber will be charged as formal variations.

Can I use prime cost or provisional sums for uncertain materials?

Use Provisional Sums for uncertain labour scopes and Prime Cost items for undefined fittings and fixtures. Under Australian domestic building legislation, each allowance must be a realistic, reasonable estimate. Clearly state your builder's margin percentage applied to any expenditure that exceeds the baseline allowance in the final invoice.

How do I quote a job I have never done before?

Learn how to quote a trade job you have never done before. Deconstruct the scope, apply true charge-out rates, factor contingency, and protect your margins.

Quick answer

Quote an unfamiliar trade job by decomposing the scope into sequential work stages, estimating exact material quantities, and applying your true hourly charge-out rate. Include a 15% to 25% contingency margin to absorb unexpected delays, and protect your business by documenting clear written exclusions for unforeseen site defects.

Skill level: All levels
Time: 4 min read
Trade: Carpentry & Joinery
Updated: 14 November 2026

Tools you will need

Bosch Professional GLM 50-27 C - Laser Measure
Stanley FatMax 8m - Heavy Duty Tape Measure
Apple iPad Air running Tradify - Trade Job Management Software
Buildxact - Estimating and Digital Takeoff Software
Pica-Dry 3030 - Longlife Automatic Pen Marker
Milwaukee M18 FUEL 2-Piece Kit - Cordless Drill and Impact Driver

The short answer

The danger with a new type of job is pricing on gut feel and discovering the cost halfway through. The fix is to decompose it: list every stage, estimate the labour hours and materials for each, and price those -- the total emerges from the parts.

Cost your labour at a true charge-out rate, not your take-home wage. It must cover super, insurance, tools, vehicle, admin time, and the hours you cannot bill. Then add a contingency (often 10-20%) for the unknowns that come with unfamiliar work, and a profit margin on top.

What it depends on

How much is genuinely unknown -- the more unfamiliar, the bigger the contingency, or quote the tricky part as do-and-charge.

Fixed price vs do-and-charge -- a written scope with exclusions protects a fixed price; hourly protects you when the scope is unclear.

Your true cost base -- under-costing overheads is the most common reason a busy tradie still makes no money.

Materials volatility -- lock in supplier pricing or add an allowance, and note it in the quote.

Your next step

Put the scope, inclusions, exclusions and payment terms in writing so any change is a paid variation. Knowing your real numbers -- charge-out rate, margin, overhead recovery -- is where an accountant or bookkeeper earns their fee. See money and business, talk to a tradie-focused accountant, or ask a specialist.

Frequently asked questions

Should I charge fixed price or do and charge for an unfamiliar job?: Charge fixed price only if the scope of work is fully defined and exclusions are documented in writing. For highly uncertain tasks, a do-and-charge hourly rate is safer. Alternatively, implement a hybrid quote: fix the price for predictable preparation work, then bill the complex or unfamiliar installation as do-and-charge.
How do I calculate an Australian tradie hourly charge-out rate?: Calculate your charge-out rate by dividing annual overheads, superannuation, vehicle running costs, insurances, and target net profit by billable hours. Most Australian sole traders only achieve 1,200 to 1,500 billable hours per year after deducting travel, administrative quoting, tool maintenance, public holidays, annual leave, and inclement weather downtime.
How much contingency should I add to an unfamiliar trade quote?: Add a 15% to 25% contingency buffer to labour and materials on an unfamiliar trade quote. This margin covers learning curves, unexpected site access restrictions, and minor material shortfalls. Ensure the contract includes explicit variation clauses stating that concealed structural defects, poor ground conditions, or non-compliant pre-existing work will incur additional costs.
How do I estimate material quantities for a job I have not done before?: Measure the site dimensions accurately and apply an industry-standard waste factor of 10% to 15%. Refer directly to manufacturer technical data sheets from Australian suppliers such as Bowens, Bunnings Trade, or Reece to confirm spread rates, fastener spacings, and fixings that comply with the National Construction Code.
What exclusions should I include when quoting an unfamiliar job?: Explicitly exclude council planning approvals, structural engineering certificates, asbestos removal, underground service diversions, and rectification of non-compliant existing services. State in your quote conditions that the pricing assumes continuous site access during standard working hours and that unforeseen sub-surface obstacles or rotten structural timber will be charged as formal variations.
Can I use prime cost or provisional sums for uncertain materials?: Use Provisional Sums for uncertain labour scopes and Prime Cost items for undefined fittings and fixtures. Under Australian domestic building legislation, each allowance must be a realistic, reasonable estimate. Clearly state your builder's margin percentage applied to any expenditure that exceeds the baseline allowance in the final invoice.

Written by Chippy, the Carpentry & Joinery specialist at WA.Tools.