This is a post I’ve been thinking about doing for a little while, but I needed the time (and the brain power of somebody much better at maths than me… thank heavens for my best beloved!) before I could pull it all together.

Some years ago when buying a bottle of perfume (Chanel, I think) and trying to decide which size bottle to buy, I noticed something odd. The available sizes were 30ml, 50ml and 100ml, but the prices didn’t seem to match up. To me it seemed that the 100ml bottle should be roughly three times the price of the 30ml, and about twice the price of the 50ml. This was not, of course, the case. Ultimately I think I bought the 50ml, simply on the basis of what I had in my bank account at the time. But I had put one foot into the murky world of “per-unit pricing”.

The strange thing is, I was already well-acquainted with the *notion *of per-unit pricing in the context of my grocery shopping. I discovered many, many years ago that (if you have the space to store it), it is always better in the long term to buy large bags of things like rice, pasta and sugar (in fact, this seems to apply to the vast majority of things in your average supermarket which come in multiple sizes), because it’s invariably cheaper to buy one big pack than buying multiple smaller packs in two or three consecutive weeks.

It never occurred to me (and I don’t know why it didn’t) until The Perfume Incident that per unit pricing would also apply to the skincare and beauty industry. And not only does it apply, it applies in a *really major* way.

In order to illustrate, I have chosen 5 items from my (well, our!) hair and beauty supplies, mainly chosen because they were things that I own more than one size of. There’s only one item where I don’t, but I do know for a fact that the smaller size exists, and I was able to find all the information I needed on it online.

So we have: one perfume, one skincare item, one cleansing item, one makeup item and one men’s skincare item. I have ordered these from least-worst to worst, leaving the very worst offender until last. I think you’ll be surprised – we certainly were.

**Kiehl’s Smooth Glider Precision Shave Lotion**

Far and away the least worst item here is the men’s skincare item. It comes in two sizes, priced as follows:

150ml at £16.00, or 11p per ml

75ml at £9.50, or 13p per ml

This means that the per-unit price is a mere **18% higher** in the small tube compared to the large one.

*(Note: the small tube in this photo is not the 75ml tube, it’s a tiny one from a gift set just for photo purposes!)*

**BECCA Shimmering Skin Perfector Pressed Highlighter**

Next up is the makeup item. Again, this comes in two sizes, priced as follows.

Standard, which contains 8 grams of product, at £30 or £4.29 per gram

Mini, which contains 2.4 grams of product, at £16 or £6.67 per g

The per-unit price is **55% higher** in the mini compact compared to the standard.

*(This is the one item that I don’t have the smaller version of.)*

**Mon Guerlain Eau de Parfum**

Next, the perfume. This one comes in three sizes, but for these purposes I have compared the smallest and largest sizes.

100ml at £96.00, or 96p per ml

30ml at £48.00, or £1.60 per ml

The per-unit price for the smallest bottle is **66% higher** than for the largest.

**Beautyblender Blendercleanser Solid**

Next, the cleansing item. This is the soap that I use to clean my makeup brushes and Beautyblenders. These two are exactly the same product, the “pro” variant is simply larger, and the bar of soap is black instead of white.

5.3oz (150g) at £40.00 or 27p per gram

1oz (28g) at £15.00, or 54p per gram

*(I converted the pack weights to grams here for consistency.)*

The per unit price is **100% higher** in the small bar when compared to the large one.

**Crabtree & Evelyn Ultra-Moisturising Hand Therapy**

With the very dubious honour of finishing in first (or perhaps last?) place here, the skincare item.

Like the perfume, this comes in multiple sizes, and I have compared the smallest and the largest. *(The photo does not represent the smallest and the largest, just the two I happen to have.)*

250g at £23.00, or 9p per gram

25g at £8.00, or 32p per gram

The per-unit price for the smallest tube is **255% higher** than for the largest. It really is. We worked it out three times. Even my aforementioned best beloved was shocked.

So there you have it.

I have yet to work out whether this is a result of the fact that it is cheaper for manufacturers to produce things in larger quantities (and that, for example, it costs more to produce three small perfume bottles than it does to produce one large one), and the per-unit price then gets reduced accordingly, or whether manufacturers are taking advantage of the fact that a lot of the time consumers simply don’t have the available funds to buy the bigger option. *Or *whether manufacturers are cheekily taking advantage of the fact that for a lot of us it’s simply convenient to have the larger size of a product at home, and the smaller size in our travel bag/car/work desk/wherever. The pragmatist in me thinks the first option, the cynic thinks some combination of the second and third. Putting my practical head on, it is very likely some combination of all three.

The net result of my investigation is this: assuming that you will use all of the contents of the larger size pack of something before it goes off, and assuming that you have the available funds to do so and the space to store it (and assuming that you don’t need the small one for a particular purpose), the chances are that it will make economic sense to choose the larger pack.

But it is *always* worth checking!