'I'm a travel expert - stop making this one mistake at the airport'

A travel guru has issued a warning to about a common mistake that could lead to unexpected baggage charges at the airport.

Jetting off for a break requires careful planning, from ensuring all paperwork is in order to packing your suitcase.

In certain situations, travellers may be required to check their luggage and if the bag exceeds size or weight limits, additional fees may apply.

Travel expert Chelsea Dickenson, also known as the Cheap Holiday Expert, has shared an important message for those heading to the with hand luggage, reports .

In a recent video, Chelsea urged passengers to exercise caution when navigating through the airport.

She warned: "If you come to the airport and your bag is slightly too big, do not go near the baggage sizer, because that is one sure fire way to highlight to the staff that you think it's too big, and they may ask you to put it in the baggage sizer.

"If it was me, I would be not going anywhere near that thing."

To help travellers avoid unnecessary charges, Chelsea offered some

She captioned her video: "The amount of people I see doing this.

"STEP AWAY FROM THE BAGGAGE SIZER PEOPLE. I am a FIRM believer that the baggage sizer is for staff and staff only.

"In my eyes, it simply does not exist - apart from when I'm doing tests for you lot!!!

"However I see people voluntarily checking the size of their bag in the airport ALL THE TIME and it's always in front of the check in desks where the staff can see you.

"Now I get it, you may be feeling a bit anxious about being asked to do it and so here's 3 tips so that you can feel better without having to do this:

"Make sure you know what your airline's luggage allowances are. They're all different and thing can change! So don't just assume that a bag you used before is gonna be okay for your next one.

"Use a bag that has the correct measurements! This is gonna help you so much as you won't be tempted into overpacking. But then just as important is... Measure and weigh your bag at home ONCE ITS PACKED. This is so key as sometimes those bags can give a little!!

"And as for all my fellow sneaky travellers who are knowingly taking a bag that's far too big... Make sure it's in your back and don't you DARE go near that baggage sizer."

You can also check the different baggage sizes for all airlines via their websites.

For , cabin bags must be a maximum size of 45 x 36 x 20 cm (including any handles and wheels) and must be kept under the seat in front of you.

If you'd also like to bring a large cabin bag on board, it has to measure a maximum of 56 x 45 x 25 cm, including any handles and wheels.

On flights, the fare types for passengers include a small personal bag that must fit under the seat in front of you, with maximum dimensions of 40 x 20 x 25 cm. For cabin bags, the maximum size allowed is 55 x 40 x 20 cm.