Cost per use: what a skincare routine really costs a day

Price per millilitre, then days per bottle

Start with price divided by volume. A £60 serum in a 30 ml bottle is £2.00 a millilitre. A £35 moisturiser in 50 ml is £0.70. A £20 facial sun cream in 50 ml is £0.40, and an £18 cleanser in 150 ml is £0.12.

Then divide the bottle by what you use. At 0.5 ml a day the 30 ml serum lasts 60 days and costs £1.00 a day. At 1 ml a day the moisturiser lasts 50 days and costs £0.70. The facial sun cream at a quarter teaspoon, which is 1.25 ml, lasts 40 days and costs £0.50. The cleanser at 2 ml lasts 75 days and costs £0.24.

Added up, that routine is about £2.44 a day, or roughly £891 over a year. The dose figures above are the convention this guide uses so that every row is comparable; they are not an official recommendation, and a smaller hand will use less of everything.

The same routine at budget prices

Repeat the arithmetic with cheaper products and the doses unchanged. A £25 serum in 30 ml is £0.83 a millilitre and £0.42 a day. A £12 moisturiser in 50 ml is £0.24 a millilitre and £0.24 a day. An £8 facial sun cream in 50 ml is £0.16 and £0.20 a day. A £6 cleanser in 150 ml is £0.04 and £0.08 a day.

That routine comes to about £0.94 a day, or roughly £343 a year. The gap between the two routines is about £1.50 a day and about £548 a year, which is the number worth having in front of you before any individual purchase.

The serum is the line that moves most in both directions. It accounts for about £1.00 of the £2.44 premium routine and about £0.42 of the £0.94 budget one, which makes it roughly 41% of the premium daily cost and 45% of the budget one. If a routine's cost is the problem, that is the step to examine first.

Sun protection is priced by the teaspoon

Facial sun cream looks cheap at £0.50 a day. Body sun protection does not, because the quantity is far larger. The NHS advises that adults should aim to apply around 6 to 8 teaspoons of sunscreen to cover the whole body, and a teaspoon is 5 ml, so one full-body application is 30 to 40 ml.

At the premium example price of £0.40 a millilitre, that single application is £12 to £16. The NHS also advises reapplying every 2 hours and straight after being in water, so a day at the coast at four applications is 120 to 160 ml and £48 to £64 of product on those figures.

That is why body sun protection is the one category where buying the large size is almost always right, and where a product bought in a 50 ml size for the body will either be rationed or thrown away unopened next summer. The routine-cost calculator on this site takes a separate body figure for exactly this reason.

• 6 to 8 teaspoons is 30 to 40 ml for one whole-body application
• At £0.40 a millilitre that is £12 to £16 each time
• Reapplying every 2 hours across a day is four applications and 120 to 160 ml
• On those figures a full day is £48 to £64 of sun cream at the premium example price
• At the budget example price of £0.16 a millilitre the same day is about £19 to £26

The open-jar figure can cost more than the price did

Period after opening is a cost line, not a safety footnote. A 400 ml body cream used twice a week at 3 ml a time is 6 ml a week, so the tub lasts about 467 days — roughly 100 days past a 12-month period after opening. On that pattern you pay for 400 ml and use about 310 ml of it.

The same arithmetic run the other way is what makes large sizes worth buying. The 150 ml cleanser above at 2 ml a day lasts 75 days, comfortably inside a 12-month figure, so nothing is wasted and the price per millilitre is the whole story.

The test is simple enough to do in a shop: divide the volume by your weekly use, convert to days, and compare against the number in the open-jar symbol. If the bottle outlasts the symbol, the effective price per millilitre is higher than the label arithmetic suggests.

Ordering from abroad adds tax before it arrives

HMRC charges import VAT on goods worth more than £135 sent to the UK, at the standard rate of 20%, calculated on the total value of the parcel including the goods, postage, packaging, insurance and any duty owed. Customs duty can apply on top above the same £135 threshold, at a rate that depends on the commodity code and the origin.

On a £150 order with £12 of shipping, the VAT base is £162 and the import VAT is £32.40, so the parcel lands at about £194.40 before any duty and before the carrier's handling fee. That is a 30% increase on the figure that appeared at checkout, and it changes every price-per-millilitre comparison you made beforehand.

Goods worth £135 or less that you bought yourself already have VAT included in the purchase price, and gifts worth £39 or less are not charged VAT. The landed-cost calculator on this site takes goods, shipping and duty as separate inputs so the three are visible rather than bundled into one surprise.

Before you buy

• Divide every price by the stated volume to get a price per millilitre before comparing anything
• Measure one dose against a teaspoon so your millilitre figures are real
• Divide the bottle size by your daily dose to get days per bottle
• Compare days per bottle against the number in the open-jar symbol
• Budget body sun protection at 30 to 40 ml per whole-body application
• Add 20% import VAT to any order above £135 coming from outside the UK
• Recalculate the daily figure whenever you change the size rather than the product

Questions readers ask

How do I measure a dose in millilitres without a syringe?

Use a teaspoon as the reference, because it is 5 ml. A quarter teaspoon is 1.25 ml, which is the facial sun cream dose used throughout this guide, and a fifth of that is roughly the 0.25 ml most serum droppers hold when half full. Measuring once with a spoon and then matching that amount by eye is enough for the arithmetic to hold.

Is a larger size always better value?

Only if you finish it inside the period after opening. A 400 ml tub used at 6 ml a week lasts about 467 days, which overshoots a 12-month figure by roughly 100 days, so about 90 ml is paid for and not used. Divide volume by weekly use, convert to days, and compare against the open-jar number before deciding.

Which step should I cut if the routine costs too much?

The serum, on these figures. It is about £1.00 of a £2.44 premium day, roughly 41% of the total, and the budget alternative in the second table costs £0.42. Moving that one line takes the premium routine from £2.44 to about £1.86 a day without touching cleansing or sun protection.

Does buying in a sale change the cost per use?

It changes the price per millilitre and nothing else. A third off a £60 serum takes it from £2.00 to about £1.33 a millilitre and from £1.00 to about £0.67 a day. That is a real saving, but it is smaller than the £1.50 a day gap between the two routines in this guide, which comes from product choice rather than from timing.

Why does VAT appear in the sums at all?

Because UK consumer shelf prices already include it at the standard rate of 20%, so the £133 of products in the first table carries about £22.17 of tax. You divide what you paid, so VAT does not change the daily figure. It matters only when comparing a UK price with a tax-free price quoted abroad, where the £135 import threshold then applies.

Sources

1. NHS — Sunscreen and sun safety (6 to 8 teaspoons for the whole body, reapply every 2 hours, the open jar months symbol) — checked 2026-11-03
2. GOV.UK — VAT rates on different goods and services (standard rate 20%) — checked 2026-11-03
3. GOV.UK — Tax and customs for goods sent from abroad: tax and duty (£135 and £39 thresholds) — checked 2026-11-03
4. GOV.UK — Making cosmetic products available to consumers in Great Britain (weight or volume and date requirements on the label) — checked 2026-11-03