How to Charge for Variations and Stop Doing Extra Work for Free

You've finished the job, packed the tools, and the customer says it: "While you're here, could you just have a look at the light in the hallway?"

Most tradies say yes. It's ten minutes, and asking for money feels petty. Then it happens on the next job, and the one after. By Friday you've done half a day of work nobody will pay for, and none of it is written down.

That's how variations leak. Not in big disputes on big builds, but in small extras that never get a price, never get recorded and never reach the invoice.

This guide shows owner-operators and small crews doing residential work how to charge for variations: which extras to price, what to say on site, when your state requires a variation in writing, and how to get every extra onto the final invoice.

What is a variation? The short answer

A variation is any change to the work you quoted: extra work, different materials, or something taken out. To get paid for one, agree on the price with the customer before you do the work, record it with the date, and list it as a separate line item on the invoice. For home-building work above your state's value threshold, any variation usually must be in writing and, in most states, agreed upon before the work starts.

How much do unbilled extras cost a tradie?

Unbilled extras cost tradies more than most think, because each one looks too small to matter.

Nobody has measured this in Australia yet, but the UK has. In a Simply Business survey of 408 UK tradespeople in May and June 2026, 92% said customers had asked them for work beyond the original booking, and 62% said it happens regularly. On average, they spent 1.8 hours per week on unpaid extra work, and over a third said they never get paid for it at all.

1.8 hours a week is 93.6 hours a year. At $100 an hour, that's about $9,400 of work given away, before you count the parts.

To work out your own number:

Here's an example. The numbers are illustrative, so plug in your own.

• You do three small extras a week that never get billed: a power point here, a tap washer there, an hour patching a wall.
• Each one is worth about $90 in time and parts.
• Over 46 working weeks, that's $12,420 a year.

That hurts more than losing a job. An extra you don't bill has already cost you the time and the parts, so every dollar of it comes straight off your profit.

Why do good tradies end up working for free?

The moment. Extras get asked for when you're mid-job or packing up, and stopping to price a ten-minute job feels like more effort than the job.

The awkwardness. Asking for $60 after a friendly chat feels mean, so you say "no worries" and move on.

No system. The extra lives in your head until the invoice gets written, often days later. By then, it's forgotten, or you're not sure what you agreed to.

The UK survey found an upside too: 62% of tradies said helping beyond the job had led to recommendations. Goodwill works. The problem isn't doing favours. It's doing them invisibly, so you get neither the credit nor the record.

Asked, found or offered: which kind of extra is it?

Every extra on a job comes from one of three places. Work out which one you're dealing with, and you'll know what to do next.

Asked: price it before you pick up the drill

The classic "while you're here". The customer asked, so all that's missing is a price. Say it out loud, as a total, before you start. Then confirm it and record it. Mark up variations the same way as the quote, or every extra lowers your margin.

Found: stop, show, then price

Hidden problems are the variations customers are most likely to question later, because they didn't ask for them. So make them visible: stop, show the customer, take a photo, and explain what it costs to fix properly. Get their OK before you carry on. If something is unsafe, make it safe first. Queensland's rules allow for genuinely urgent work, but the written variation still has to follow.

Offered: quote it, don't start it

This is the one most tradies get wrong without knowing it. If you suggest extra work at the customer's home and they agree on the spot, it may be an unsolicited consumer agreement under the Australian Consumer Law. South Australia's Consumer and Business Services uses exactly this example. Over $100, the rules for unsolicited agreements require a written agreement and a 10-business-day cooling-off period, and, with very limited exceptions, you can't do the work or accept payment during that time.

The fix: when the extra is your idea, and it isn't urgent, quote it and let the customer come back to you. CBS says a customer who calls to go ahead after getting your quote isn't an unsolicited sale. It also takes the pressure off, which customers remember.

What do you say when a customer asks for extra work?

Keep it short and friendly, with a number in it. The aim is to make the price a normal part of the conversation, because it is.

Then confirm it in writing the same day. For most small jobs, a text does it:

One text turns "I'm sure we talked about it" into a dated record. For larger jobs covered by your state's building contract rules, a text alone may not be enough. That's the next question.

Do variations need to be in writing?

Variations on home-building work usually need to be in writing once the job exceeds a value threshold, and each state sets its own threshold. Here's how they compare as of October 2026.

Most small jobs sit under these thresholds. That doesn't make a verbal variation safe. If it's disputed, a dated text with the price is what gets you paid.

Extras can push a small job over the line. The QBCC's small building projects contract warns that if variations take the total past $3,300, obligations such as home warranty insurance may apply. Watch the running total, not just the extra.

Over the threshold, a text isn't the whole answer. Rules in Queensland and Victoria set out what the variation document must contain and require the owner's written agreement before the work starts. The QBCC publishes free variation forms with its contracts.

How do you make sure extras end up on the invoice?

Pricing the extra is half the job. The other half is making sure it's still there when you write the invoice.

Log it when it happens. Record each variation on the day: the date, what it was and the agreed price. Anything left in your head until invoice day is at risk.

Give each variation its own line. "Additional work: $940" is the line customers query first. "VAR-0001: 2 x double power point, kitchen: $360" is one they recognise and pay.

Bill the favour at $0. If it took two minutes and no parts, do it, but put it on the invoice anyway: "Replaced two tap washers, laundry: no charge." The customer sees the favour, and you've got a record of what you did. Set your free-favour limit in advance, say under ten minutes and no parts.

Show credits too. A credit line for work you didn't need to do makes every other line easier to trust.

Bill variations as you go on long jobs. If a job runs over a few weeks with progress payments, add agreed variations to the next payment so they don't pile up into one big surprise.

What's the best way to record a variation?

There's no single right way to record a variation. What matters is that it's priced, dated and still there when you write the invoice. Here's how the usual options compare.

How do you stop extras catching you out?

The cleanest variations start with the quote. If it says what's included and what isn't, a variation is obviously a variation.

Add an exclusions line to every quote listing what you haven't allowed for, such as patching and painting after electrical work, rubbish removal, or anything hidden behind walls. Then add one sentence: "Any extra work or changes will be priced and agreed with you before we do them." It sets the expectation before the first "while you're here", so on site you're just doing what you said you'd do. And if quotes are going quiet before you get that far, here's how to follow up a quote.

How does Korda Pro handle variations?

Korda Pro is quoting and invoicing software for Australian trade businesses that turns a voice note into a quote or invoice, then chases the customer until the job is paid. Variations work the same way: by voice, from site.

When the job changes, send a WhatsApp voice note while you're standing there: "Variation for the Smith job, two extra double power points in the kitchen, $180 each." Korda Pro logs it against the job with its own number, such as VAR-0001, and confirms it in the chat.

When you invoice the job, each logged variation is automatically added as its own line item, and the invoice is saved to Xero. Credits come off the total the same way. Ask "What extras have I logged for Smith?" at any time to see the list.

Korda Pro records variations so they get billed. It doesn't collect your customer's signature, so use a signed variation document where your state requires one. And it isn't job management software. It looks after the part of the business that turns work into money.

Setup takes under 20 minutes, with a 14-day free trial and no credit card.

What variation mistakes should you avoid?

• Doing it first and pricing it later. If the invoice is the first time the customer hears the price, you're negotiating after the work is done.
• Lumping extras into one line. "Additional work" with no detail is the line that gets queried.
• Trusting your memory. The extra you'll definitely remember is the one that's gone by Friday.
• Leaving credits off. Customers notice, and it makes the rest of the invoice look less trustworthy.
• Missing the running total. A few small extras can push a job over your state's contract threshold.

Variations FAQs

The bottom line

Extra work isn't the problem. Extra work without a price, a record and its own line on the invoice. Price it before you start, confirm it in writing, and bill it as its own line, even when the line says $0.

Do that on every job and "while you're here" stops being a favour you quietly absorb and becomes work you get paid for.