Advent calendars used to mean a bit of chocolate behind a cardboard flap. Today you can get calendars filled with beauty products, tea, spices, beer, socks, tools or collectible figures, and some of them cost as much as a weekend's grocery shop. If you want to buy an advent calendar, by October you are facing a wall of offers, and almost every one of them advertises a value far above its price.

Whether a calendar actually adds up can be answered fairly well with a bit of mental arithmetic. You need three things: the price, the number of doors and an honest list of what is inside. The rest is simple maths and a little self-knowledge.

Price per door: the number that matters most

Divide the purchase price by the number of doors. That sounds obvious, but it changes how you look at the offer. Not every calendar has 24 doors. Some have 12, some 25 or more, and behind some doors there is only a card with a saying on it or a discount code rather than an actual product. Only count the doors hiding something you would really use.

Then compare the price per door with what you would pay in a shop for a single product of that kind. A tea bag is not worth several euros, and neither is a sample tube of hand cream. For food, the unit price helps: how much does the chocolate in the calendar cost per 100 grams compared with a normal bar? There is more on this in the article on shrinkflation and unit prices.

The advertised advent calendar value

Many calendars advertise "contents worth" a figure that is well above the price. This value is usually calculated like this: the samples are valued in proportion to the price of the full-size pack and then added together. A mini tube holding a tenth of the contents is therefore counted at a tenth of the shop price, or sometimes more generously.

That is not wrong as a calculation, but it tells you very little about what the calendar is actually worth to you. You would never buy most of these products in full size. Much like a recommended retail price, the stated value is mainly a reference figure chosen by the seller itself.

Worked example: 89 euros for 24 doors

Say a beauty calendar costs 89 euros and has 24 doors. That comes to 89 divided by 24, or about 3.71 euros per door. The seller states a value of 250 euros. Behind that are 6 full-size products at 15 euros each, 90 euros in total, and 18 samples each valued at 8.90 euros, 160.20 euros in total. That makes 250.20 euros.

Now for the honest list. Of the 24 products, you would genuinely use 12. That means you are paying 89 divided by 12, or about 7.42 euros, per useful door. If those 12 include the 6 full-size products you would otherwise have bought anyway for 90 euros, the calendar was worth it. If they are mostly samples, probably not.

Advent calendars for adults: what to look out for

Calendars for adults are often more expensive and more narrowly themed. With beer, wine or spirits, the bottles are small and the price per litre is usually well above what you would pay buying normally. With beauty products, it is worth checking the ingredients, especially if you have sensitive skin. If certain ingredients do not agree with you, check beforehand whether the list of products has been published. You will find tips on shelf life and batch numbers in the article on cosmetics: batch numbers, shelf life and skin tolerance.

Another point: many calendars contain products that repeat or that you already own. Some sellers reveal the full contents in advance, while others keep them secret. A calendar with an open list is much easier to judge.

Calendars for children

With children's calendars containing figures or building bricks, the question is a different one. Here it is less about value and more about the fun of opening the doors, and about safety. Check the age recommendation on the packaging. Small parts are a problem for younger siblings, even if the calendar is really meant for the older child. What these labels point to is explained in the article on toys: age labels and safety standards.

With chocolate calendars, it is worth looking at the weight. Two calendars in the same size box can contain very different amounts, and the best-before date should run well past December.

Fill it yourself or buy it ready-made

The alternative is an empty calendar that you fill yourself. Say you put something costing 3 euros on average behind each of the 24 doors: that comes to 72 euros, plus the calendar itself. That is not necessarily cheaper, but every door holds something that suits the person. If you buy the individual items in bulk, it is still worth checking whether the multipack is really cheaper than buying them separately.

Timing, delivery and returns

The best choice is available in the autumn. Popular calendars often sell out as early as November. After the first of December, on the other hand, prices drop, sometimes considerably, because hardly anyone wants to start a calendar on day five. If you look closely at price reductions, shops in the EU have to show the lowest price of the previous 30 days. That lets you see whether a discount is genuine. Other countries have their own rules on this.

If you order online, allow enough time for delivery. A calendar that arrives on the third of December loses much of its point. Within the EU, online purchases come with a 14-day right of withdrawal, but as soon as you open doors and use the products, returning it is practically no longer an option. Outside the EU, for example in the UK, the USA, Canada or Switzerland, different rules apply. There is more on timing in the run-up to Christmas in the article on Christmas shopping: delivery times during Advent.

Frequently asked questions

How do I work out the price per door?

Divide the purchase price by the number of doors that actually hide a product. It is even more telling to count only the products you would really use.

Is the advertised value of an advent calendar accurate?

It is usually an extrapolation: samples are valued in proportion to the price of the full-size pack. That says little about what the contents are actually worth to you.

When are advent calendars cheapest?

Prices often fall after the first of December. By then, though, the choice is smaller and the first few days have already gone. For your own use it can still be worth it.

Can I return an advent calendar once it has been opened?

Once doors have been opened and products used, usually not. For unopened calendars bought online in the EU, the right of withdrawal generally applies; outside the EU, for example in Switzerland, the UK or North America, different rules apply.