Every year the Royal Mint releases unique coins to mark international events, big occasions and anniversaries but how can you tell whether the change in your purse or dropped into a piggy bank is worth something?

From commemorative collections to special editions in circulation, we take a look at how households can try and understand the potential value of a coin they have at home.

Is it a commemorative or circulating coin?

Understanding whether your coin is a commemorative coin or has been in circulation is the first step, says the Royal Mint, in understanding its value.

Commemorative coins are made as collectors items and gifts, which are often individually packaged and tend to remain in excellent condition because they will never find themselves among our regular money.

They also come in a variety of metals - including silver and gold - which can obviously affect a commemorative coin's value alongside whether it has its original packaging and any certificates of authenticity.

Anyone attempting to establish the worth of a commemorative coin is also advised to check if its still for sale through the Royal Mint and therefore what its current recommended retail price might be.

There are also other reasons why a particular commemorative coin may become more valuable over time.

For example, coins released this autumn to celebrate 100 years of the BBC featured the Queen's profile because they had been struck prior to the monarch's death and a decision was taken to proceed with the design to prevent waste. As a result coin experts believe they will come to hold more significance as one of the last commemorative coins to feature Queen's Elizabeth's image.

The coins in your pockets and purses however are circulating coins.

New coins are released to bank and post offices each year and these endure considerable wear and tear as they change hands far more regularly.

Among them can be special edition 50p pieces - the most ideal shape for a one-off design - and £2 coins.

The next new coin expected to be released into circulation in the UK is a new 50 pence - and the first to feature the profile of our new King Charles III. Officials at the Royal Mint have already started manufacturing the coins, which are expected to begin appearing among people's change from mid-December and there is expected to be considerable interest in getting one of the first new to be released.

Know the mintage

The 'mintage' refers to how many of a particular coin were made and can therefore be used to determine exactly how rare your coin might be.

While most coins have a mintage running into millions, the lowest mintage for a circulating coin in recent years was that given to the 2009 50p featuring Kew Gardens at just 210,000 pieces. And when the Royal Mint released into circulation 1.3 million new 50p coins marking the Queen's Platinum Jubilee through Post Office counters in February officials expected a rush for them because of a relatively limited release for such a significant coin.

Mintage numbers for circulating coins are available to view on the Royal Mint website here.

Look at the design

A coin's design can influence how much people are willing to pay for it. For example, explains the Royal Mint's website, a series of special 50 pence pieces made 10 years ago to mark the 2012 Olympics may see a small resurgence in popularity this year as people look back on the event a decade later.

Similarly - special £5 commemorative coins released earlier this year for the Queen's Platinum Jubilee, which included the late monarch's signature 'Elizabeth' are now likely to carry even more significance as a result of her death in September.

The Royal Mint's website also found itself overwhelmed with visitors in mid-November when it put on sale the first Sovereign or 'chief' coin to feature the profile of King Charles.

Any coin that commemorates an anniversary or a key theme can hold special significance that might mean certain collectors are willing to pay more for it.

Other releases by the Royal Mint in recent years include coins to mark the life of Beatrix Potter, The Representation of The People Act, and our exit from the EU.

Mint condition?

Like any item you might be looking to resell - from a second hand car to clothing - condition will also be key. The closer the coin looks to being in 'mint condition' - the condition it was in when it left production lines at the Royal Mint - the higher its value has the potential to be.

Coins can also be referred to in grades as the Royal Mint's own website explains: "The quality of a coin describes the finish of the coin when struck and there are three different standards to describe this: Proof, Brilliant Uncirculated (BU) and Bullion.

"Grading, in comparison, relates to the condition of a coin in terms of its appearance and the amount of wear that it has received, either in the hands of collectors or in circulation. The terms used in the UK are Fine, Very Fine, Extremely Fine and Uncirculated."

Uncirculated, as the term suggests, refers to money that has never been used as change and so is likely to have retained its look and finish - these are often coins collectors have been quick to get their hands on.

Extremely fine coins have minimal scratches or just small signs of having been in circulation, Very Fine have limited signs of wear and tear while Fine coins will have seen considerable use.

You can learn more about obtaining money in 'mint condition' and assessing the condition of your coin here.

Is the coin pre-decimal?

In 1971 decimalisation took place giving us the money we recognise today.

Since then, the pound has been divided into 100 pence but before February 1971, 12 pence made a shilling and 20 shillings made a pound. British coinage also included the sovereign, crown, half crown, sixpence, half penny and farthings.

People who find pre decimal coins, says the Royal Mint, may struggle to pinpoint its mintage and the advice is to consult an expert - or numismatist. The Royal Mint itself offers valuation services and access to staff with a wealth of knowledge.

Prices for an appointment can start, according to its website, from £20.