Free template
Write the variation like the invoice depends on it. It does.
Most unpaid extras aren't refused — they're just never written down, so there's nothing to point at when the invoice lands. A variation letter is the written-down version: one page, seven things in it, signed before the work starts. Copy the template below straight off the page.
Copy-ready template Seven things it must contain Works for any trade
01 — When a letter is the right tool
Three moments that need paper, not a promise.
Write one when the customer asks for something that wasn't in the quote — the classic “while you're here”. Write one when you find something that changes the job: the board's worse than the photos suggested, the wall's hiding galv, the span needs more steel. And write one before you start any work whose price wasn't in the original number — not during, not at invoice time.
A letter suits the jobs that run on paper: builders emailing a owner mid-reno, subcontractors answering a site instruction, anyone whose customer is at a desk. If you're on site with the customer standing next to you, paper is the slow version — that's the moment a phone signature exists for, and the end of this page covers it.
02 — What it has to contain
Seven things. Miss one and it's a note, not a variation.
1. What it varies
Name the original quote or contract and its date. A variation floats free of nothing — it has to point at the thing it's changing.
2. The change, in plain words
What work is being added, swapped or dropped. Two sentences a homeowner can read, not a spec clause.
3. Why
One line. “You asked for it” and “we found it when we opened the wall” are both fine reasons — the point is the customer can't later say it came from nowhere.
4. The price, all the way to GST
Ex-GST, the GST, and the total including it. “About $400” is how the argument starts — the number they sign is the number that's hard to un-remember.
5. The time impact
Days added, even if it's zero. The delay conversation at the end usually traces back to a variation that never mentioned time.
6. Photos, if they explain it
Attach or reference them. A photo of what you found is worth a paragraph of persuasion, and it dates itself.
7. Both signatures and the date on each
Their approval and your commitment, with a date on each. One signature is a memo; two is an agreement.
03 — The template
Copy this. Fill the brackets. Send it before you start.
VARIATION TO QUOTE / CONTRACT #[number] From: [your business name and ABN] To: [customer name] Site: [job address] Date: [today's date] Original scope: [the quote or contract this changes, and its date] Change requested by: [you / the customer] What changes: [plain description of the extra or different work] Why: [one line — "found X when we opened Y", or "you asked for Z"] Price for this variation: $[amount] + GST = $[total] including GST Time impact: adds [X] working day(s). New completion estimate: [date] No other part of the original scope or price changes. Approval to proceed: I, [customer name], approve this variation at the price above. Customer signature: ____________________ Date: __________ Contractor signature: __________________ Date: __________
Send it by email so the whole thread lives in one place, and make the ask explicit in the covering line: “Reply APPROVED and I'll book it in.” If they sign and return it, file the thread with the quote. If you'd rather skip the printing and scanning entirely, the section below is the faster version of the same habit.
04 — What makes it stick
In a dispute, the wording is the whole game.
Electronic signatures are recognised in Australia under the Electronic Transactions Act and its state equivalents — a typed name and the date can carry the same weight as wet ink. But what usually decides an argument isn't the signature on its own. It's whether you can show what was agreed, when it was agreed, and that both sides were looking at the same words. The template above is built around exactly those three things.
For residential building work, written variations aren't just good practice in some states — NSW home building contracts over $5,000 carry a written-variations term, and the industry contracts from HIA and Master Builders have their own clauses. This isn't legal advice. If you're in a live dispute, or the contract is large or unusual, talk to someone qualified.
Straight answers
Questions people actually ask.
Is a variation letter legally binding?
A signed variation is a change to your agreement, and electronic signatures are recognised under the Electronic Transactions Act and its state equivalents. What usually decides a dispute is whether you can show what was agreed, when, and that both sides saw the same words — which is why the letter carries the scope, the price, the time impact and both signatures. This isn't legal advice; for large or high-risk contracts, have your terms reviewed by a lawyer.
Can I send a variation by text or email instead?
Yes — the format matters less than the content and the record. An email thread with the seven things in it and a clear approval beats a formal PDF nobody signed. A photo-and-price text message shows you sent a number; it doesn't show they read it, agreed to it, or knew what it covered. Whichever format you use, get an unmistakable yes against the full wording.
What if the customer doesn't reply?
Don't start the varied work. An unsigned variation is the hardest money in the trade to collect, because the argument happens after the work is done and everyone's memory has improved. Chase it once, in writing. If it's urgent — a safety issue — make safe, document what you did and why, and price the rest before continuing.
Does the price have to be exact?
Where it can be, yes. Where it genuinely can't be — you don't know what's behind the wall — price the mechanism instead: the hourly rate, the day rate, or the unit rates the final figure will be worked out from, with a cap if they'll agree to one. What you can't leave blank is how the number gets decided. That's the bit disputes are made of.
The next one's coming
The next “can you just” is already on its way.
Price it on your phone, they sign on theirs, you both keep the PDF. Under A$500 it costs you nothing, ever.
No card, no trial clock. Your customer doesn't need an account.