Where the Supermarket Gap Between NZ Chains Actually Is

Every week I read the price of the same 20 lunchbox staples from Woolworths' and Pak'nSave's own online shops and publish the table. The figures below are from the round read on 18 October 2026 (Woolworths) and 18 October 2026 (Pak'nSave). They update when the tracking does, so the numbers you are reading are the current round, not a frozen snapshot of when this was written.

Every Pak'nSave row in this round was read within a week of the Woolworths one.

The headline is unremarkable: on the 19 items priced at both stores, Woolworths comes to $97.80 and Pak'nSave to $87.64. A difference of $10.16, or about 10.4%.

That number is lower than most people expect, and on its own it is not very useful. The useful part is where the difference sits.

Four items carry most of it

Those 4 lines account for about 63% of the entire gap. The other 15 rows share the rest, and they do not all lean the same way.

This is the practical finding, and it is not the one the "Pak'nSave is cheaper" shorthand gives you. If you do one shop a week at one store, you are not losing money across the board by picking the wrong one. You are losing most of it on apples, sliced chicken, cheese block and wholegrain bread. A household that buys those four things somewhere cheap and everything else wherever is convenient captures most of the available saving without driving anywhere twice.

And it is not one-way

Woolworths is cheaper on cherry tomatoes (180g), lettuce (iceberg) and sliced ham (200g).

One of those is worth pausing on. Lettuce (iceberg) is $0.79 cheaper at Woolworths — smaller than any of the rows above, but running the other way. Fresh produce moves week to week and is the least reliable part of any "which supermarket is cheaper" claim, including mine.

The winner changed on three items

The index keeps every reading, and comparing two of them — the first full round, 16 May 2026, and the latest, 18 October 2026 — lets me ask something a single round cannot. Not who is cheaper, but whether who is cheaper stays put.

Of the 14 items priced at both chains in both rounds, Pak'nSave was cheaper on every one of them back in May and is cheaper on 11 now. Three rows changed hands, every one of them from Pak'nSave to Woolworths.

Of the three, one changed hands because the losing chain went up and one because the winning chain came down.

That distinction is the whole value of comparing two rounds. Take the widest of them, lettuce. "Woolworths got cheaper" would be a reason to shop there. "Pak'nSave put it up" is a reason to look at the price of that one item wherever you shop — and it is the one the data actually supports.

Two rounds five months apart, with the readings in between set aside, is the weakest possible version of this test. Four of the 19 rows could not take part at all — wraps 6-pack, cherry tomatoes, hummus and peanut butter had no comparable pair of figures in 16 May 2026, mostly because those are the rows whose spec I had to change. Three rows do not prove anything; this is a first look.

What is not in the table, and why

and eggs — every one of them because the Pak'nSave price that week was a special, and a special is not a shelf price.

A special price is not a shelf price. If you let specials into an index, the index starts reporting deflation every time something goes on promotion, which is the opposite of what a price index is for. Those rows keep their last regular figure and sit out the comparison rather than being estimated. An estimated number in a price index is worse than a missing one.

Three rows changed definition along the way. They had been stuck for months because the spec I had written down did not exist at both chains: an 8-pack of wraps Woolworths does not sell, loose Royal Gala apples my Pak'nSave does not stock, and a 200g hummus tub that turns out to be 220g at both. Each is now pinned to a product both stores actually carry. That makes those rows useful from here on and useless for looking backwards — an older figure for them measured something else.

What I would not claim

The 16 May 2026 round was checked in store at both chains; every later round comes from the chains' online Click & Collect prices, and online and shelf prices can differ — so part of any May-to-now change could be that switch rather than the shelf. Pak'nSave prices by store, and mine is Ormiston, so this is one store's answer rather than the country's. And the index only started pinning each row to a specific product code on 30 July 2026 — figures from before that were collected against the same written specs but without the brand recorded, so an individual percentage from the older rounds is worth less than the pattern it sits in.

New World is now in the index too, and the three-chain comparison — which chain wins which row, and which aisle the gap actually comes out of — is in Three NZ Supermarkets.

A basket total is also not a lunchbox. The same tracked prices, divided by how much of each pack one lunchbox actually uses, are in The shelf price is not the lunchbox price — where the cheap-looking items turn out to be the expensive ones.

The full table, with every row's date and the reason for each exclusion, is on the NZ Lunchbox Price Index page. Every figure above is also in price-index.csv — one row per chain per item, with the pinned product name, its SKU, the pack size and the date that price was read — so the totals and the gap can be rebuilt from the raw rows rather than taken on trust. Published under CC BY.

What I will be watching

How much of this is even movement is a fair question, and I have started answering it separately: what actually moved across every reading so far counts how many of these items changed price at all.

Whether the four-item concentration holds. The May round gives a first partial answer. On the 14 rows priced at both chains in both rounds, the four widest gaps made up 44% of the Woolworths–Pak'nSave difference in 16 May 2026 and 90% in 18 October 2026, and two of those four rows are the same in both rounds. If the gap stays in the same few rows month after month, that is a genuinely actionable finding for anyone packing lunches, and it is more useful than a single percentage that changes every week. If it moves around, that is worth knowing too, and it would mean the tidy advice above was an artefact of a single round.

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