A CPI-linked price rise is the easiest increase to justify and the most tedious one to apply. The rate is not yours to argue about — a statistics agency published it — but Xero still makes you open every repeating invoice template and retype every line.
This guide covers both halves: getting the number right, and applying it across the whole book in one pass.
What a CPI increase actually is
CPI — the Consumer Price Index — measures how much a representative basket of goods and services has risen in price. When a contract says fees increase “in line with CPI”, it means the annual percentage change in that index, published by the national statistics agency:
| Country | Agency | Series to use |
|---|---|---|
| New Zealand | Stats NZ | CPI, annual % change, latest quarter |
| Australia | ABS | CPI, annual % change (All groups, eight capital cities) |
| United Kingdom | ONS | CPIH or CPI, 12-month rate |
| United States | BLS | CPI-U, 12-month percentage change |
Two details catch people out every year.
Use the annual change, not the index level. The index itself is a number like 1,285. The figure you want is the percentage change over twelve months — usually a single digit.
Use the quarter your contract names. CPI is published quarterly in New Zealand and Australia, monthly in the UK and US. A contract that says “the CPI figure published for the year to 30 June” means that specific release, not whichever one is newest when you get round to invoicing. Applying a later, higher figure because it happened to be out is the kind of error a client will find.
Turning CPI into a rate you can defend
Read the contract before you read the index. The wording decides the rate.
- “Fees will increase in line with CPI” — the CPI figure, unmodified. If it is 2.7%, your rate is 2.7%.
- “CPI plus 2%” — additive, so 4.7% on a 2.7% CPI. Common where costs rise faster than the general basket.
- “The greater of CPI or 3%” — a floor. In a low-inflation year the floor applies.
- “CPI, capped at 5%” — a ceiling, usually negotiated by a larger client.
- Silence on CPI entirely — then it is not a CPI rise, it is a price rise, and it needs the notice period your contract specifies for one.
Write the resulting rate down with the release it came from before you touch anything. When a client queries the invoice in four months, “Stats NZ CPI, year to June 2026, 2.7%” ends the conversation. “About three percent” does not.
Why applying it in Xero is the hard part
Xero has no bulk edit for repeating invoices. There is no multi-select, no find and replace, and no CSV round-trip for templates. The accounting API has no update call for a repeating invoice either — only create and delete — so the limitation is structural rather than a missing button.
That leaves the manual route: open a template, edit each line’s unit price, save, go back, open the next one. On a book of 120 templates averaging three lines each, that is 360 individually retyped prices.
The cost is not only the hours. A CPI rise applied by hand goes wrong in specific ways:
- Arithmetic drift. 2.7% on $1,450 is $1,489.15. Typed at speed, across hundreds of lines, some of those will be wrong — and each wrong one bills incorrectly every cycle until somebody notices.
- Missed templates. Nothing in Xero marks a template as done. Interrupt the job halfway and the only record of where you stopped is your memory.
- No before-and-after. Once a template is saved, the previous prices are gone. If a client disputes the rise, you cannot show what it was.
- Inconsistent rounding. Some lines get rounded to the dollar, others keep the cents, depending on who did that row and when.
Decide the rounding rule first
A raw CPI calculation produces prices like $1,489.15. That is defensible — it is exactly the rate — but most books read better rounded, and rounding is a decision worth making once rather than per line.
- To the dollar suits most service books. $1,489.15 becomes $1,489.
- To $5 or $10 suits larger contract values, where cents are noise.
- Not at all is the right answer when the contract ties the fee precisely to CPI and a client is likely to check the arithmetic.
Rounding should never reverse the increase. If 2.7% on $10.20 rounds down to $10.00 at a $5 step, the original price should stand instead — a “rise” that lowers the price is a mistake in any book.
Set a minimum increase for your small lines
A percentage produces trivially small changes at the bottom of a book. Applied to a $12 monthly line, 2.7% is 32 cents — it costs more in client confusion than it earns.
A minimum-increase floor fixes this: “2.7%, or at least $2, whichever is larger”. It lifts the small lines to something meaningful while leaving the large ones exactly on the CPI rate. The order matters — the rate sets the target, the minimum lifts anything that came out too small, and rounding is applied last.
Applying it across the whole book in one pass
Invoice X does this specific job. It connects to your Xero organisation through Xero’s standard OAuth flow, loads every repeating sales invoice, and applies one rule across the templates and lines you select.
- Load the book. Every repeating sales invoice, with its lines, current prices and next run date. Bills are counted and skipped — a CPI rise on your revenue should never touch what you owe.
- Set the rule. The CPI rate as a percentage, plus the minimum increase and rounding step you decided above, and the date the new prices start.
- Read the preview. Every line’s old price and new price, and the total movement per billing cycle. This is the point to check the arithmetic — before anything is written, not after.
- Push. Each changed template is rebuilt and verified field by field against what was intended, and the original is only retired once the replacement is confirmed. If verification fails, the original keeps running.
The preview cannot disagree with the result, because Apply runs the same calculation that produced the preview. See how it works for the full walkthrough, or the feature detail for the rounding and minimum-increase rules.
Choosing the start date
New prices should begin on a clean billing boundary — the first invoice of the new financial year, or the anniversary of the contract, not the middle of a period a client has already been billed for.
A start date cannot be usefully moved backwards. A template whose next run has already passed the date you set will simply run at the new price on its next cycle; it will not re-bill periods it has already invoiced.
Tell clients before the invoice arrives
A CPI rise is the easiest increase to explain, and still the one most often mishandled — because the first a client hears of it is a larger invoice.
Send the notice before the first uplifted invoice runs, with the notice period your contract requires. Name the index, the release and the figure, state the new price, and give the date it starts. A CPI rise announced properly is almost never disputed; the same rise discovered on an invoice frequently is. For wording, start from these price increase letter templates for recurring clients — the first one is written for a CPI rise.
Check the result is worth what you expected
After the push, the point of the exercise is the revenue difference. The repeating-revenue forecast projects your authorised templates forward month by month, so you can compare the book before and after the rise and confirm the increase landed where you thought.
Common questions
Can I apply different CPI rates to different clients?
Yes, and often you have to — contracts signed in different years reference different releases, and some carry a floor or a cap. Run the book in groups: select the templates on one rule, apply and push, then move to the next group. Each pass is previewed separately.
What if a client’s contract caps the increase?
Apply the uncapped rate to everything else, then handle the capped templates as their own pass at the capped rate. Trying to hold the exceptions in your head while working through a single large selection is how the wrong client gets the wrong rise.
Does changing a product’s price in Products and services update my repeating invoices?
No. Xero’s repeating invoice templates store their own unit prices, copied at the time the template was created. Changing the item afterwards affects new documents, not existing templates. This is the single most common assumption behind a price rise that silently did not happen — it has its own guide, including how to check whether it has already cost you.
Does this work on multi-currency books?
Yes, scoped per currency, so you never work against a total summed across currencies. A CPI figure belongs to one economy; applying a New Zealand CPI rate to your USD contracts is rarely what the contract says.
What does it cost?
One plan at $29 USD a month for up to five users, with no per-invoice fees. A single annual price rise usually pays for the year.