What the Baggage Allowance Planner does
This planner checks each of your bags against the size and weight limits of your ticket - maximum length, width and height, maximum linear size (length + width + height), weight per bag, number of pieces and total weight - and, when a bag is too heavy, works out how much weight to move into which other bag so everything fits.
You enter the limits from your own booking, because airline allowances differ by airline, route, fare and frequent-flyer status and change often. The only built-in figure is IATA's published cabin-bag size guideline, and it is labelled as a guideline.
How to use it
- Choose centimetres and kilograms or inches and pounds.
- Copy the limits from your booking confirmation or the airline's baggage page into the table: a maximum size for cabin bags and personal items, and usually a linear limit and a weight for checked bags. Leave any box empty if that limit does not apply to you.
- List your bags, one per line: a name, the type (cabin, personal or checked), the three measurements and the weight. Measure with wheels and handles included and weigh with a luggage scale.
- Read the result for each bag, then the suggestions: which bag to move weight out of, how much, and where it can go without breaking another limit.
Reading the results
Size is checked largest side against largest limit, middle against middle and smallest against smallest, because you can turn a bag to fit a sizer. A bag of 56 x 38 x 22 cm fails a 55 x 40 x 23 cm limit on its longest side even though its other sides have room.
Linear size is the sum of the three dimensions. Many checked-bag rules are written this way - 158 cm, or 62 inches, is a very common figure - so a long thin bag and a short fat one can both pass.
Rebalancing moves weight only into bags that still have spare allowance, in steps of 0.1 kg, fullest-headroom first. If weight is left over, no combination of your bags can carry it, and you need to remove items or buy more allowance.
Worked example: a family with one overweight suitcase
The booking allows each passenger one checked bag of up to 23 kg and 158 cm linear, one cabin bag of 55 x 40 x 23 cm up to 10 kg, and one personal item of 40 x 30 x 15 cm. The family has a large suitcase measuring 78 x 52 x 31 cm weighing 26.4 kg, a duffel of 70 x 35 x 30 cm at 16.2 kg, a 56 x 38 x 22 cm wheelie at 8.5 kg and a backpack.
The suitcase fails twice: 78 + 52 + 31 = 161 cm is 3 cm over the linear limit, and it is 3.4 kg too heavy. The duffel has 23 - 16.2 = 6.8 kg of headroom, so the planner suggests moving 3.4 kg into it.
The wheelie is within its weight but its longest side, 56 cm, is 1 cm over the 55 cm limit - a common surprise with bags sold as "cabin size". The size problems cannot be fixed by moving weight; the report says which bag needs changing.
Formulas and scoring rules
- Linear size
linear = length + width + height- Fits the size limit
sort(bag) <= sort(limit), side by sideBoth sorted from largest to smallest.- Headroom
headroom = weight limit - bag weightPositive headroom can take weight from an overweight bag.- Units
1 in = 2.54 cm; 1 lb = 0.45359237 kgConverted exactly; results are rounded to 0.1 for display.
Limitations: what the result does not prove
- No airline rules are built in: they change too often to ship honestly. Check your airline's current page and your booking.
- Rebalancing is about weight only. It cannot tell whether a heavy item physically fits into the other bag, or whether an item is allowed in the cabin or the hold at all.
- Liquids, batteries, sharp objects and dangerous goods have their own rules that no size or weight check covers. Spare lithium batteries and power banks usually must travel in the cabin.
- Airport scales and sizers are what count on the day. Leave a margin of a few hundred grams and a centimetre or two.
Privacy: where your data goes
Everything you paste, type or drop is processed in this browser tab. It is not uploaded, logged, stored or sent to analytics. Session recording and tag-manager scripts are switched off on this page.
Standards and sources
- IATA - Responses to frequently asked questions on the Cabin OK optimum size guideline
- NIST - SI units of length and mass (inch and pound definitions)
Frequently asked questions
What does linear inches or linear centimetres mean for luggage?
It is the total of a bag's length, width and height, including wheels and handles. A limit of 62 linear inches (158 cm) is common for checked bags: a 30 x 20 x 12 inch case is exactly 62 and passes, while 30 x 21 x 12 is 63 and does not.
Is there a standard carry-on size for all airlines?
No. In 2015 IATA proposed a "Cabin OK" optimum size of 55 x 35 x 20 cm, but it is a guideline that airlines are not obliged to adopt, and allowances still vary widely. You can load that guideline as a starting point, then correct it to your airline's figures.
Can I move weight from my checked bag to my carry-on?
Only if your cabin bag has a weight limit with room to spare, or no weight limit at all - some airlines do not weigh cabin bags on some routes. The planner treats a bag without a weight limit as unchecked, so it will not suggest moving weight into it.
Should I measure my bag with the wheels included?
Yes. Airline limits and gate sizers include wheels, handles and side pockets. Manufacturers sometimes quote the size of the body only, which is why a bag sold as cabin size can be a centimetre or two over.
What if my bags are over the total weight allowance?
When the total weight is over, no rebalancing helps: the planner reports how much has nowhere to go. Your options are to remove items, wear the heaviest clothing, or buy extra allowance in advance, which is usually cheaper than paying at the airport.
Last reviewed by the A2Z.Tools team against the sources listed above.
