My bag is 51 pounds. Will they charge me?

On most airlines, yes, if the agent weighs it. The standard limit is 50 pounds on most US airlines and 40 pounds on Frontier. American charges $30 for over 50 to 53 pounds, while Delta charges $100 from 51 to 70 pounds. Moving a pound or two into your carry-on is usually the cheapest fix.

Can I move stuff into my carry-on at the counter?

Yes, as long as your carry-on or personal item still fits the cabin size limit. Step to the side, move the heaviest items, and weigh the bag again.

What happens if my carry-on is too big at the gate?

On fares that include a carry-on, it is often checked, but rules vary by airline. On strict fares you pay. United Basic Economy charges $75 at the gate, compared with $50 in the lobby.

If they gate check my bag because the bins are full, do I pay?

American says it valets larger carry-ons on regional planes at no charge. Other airlines do not publish one rule, so ask the gate agent, and remember strict fares charge for bags that fail the sizer.

Can I prepay an overweight fee online?

Not on United. United says oversized and overweight bags must be paid at the airport. Other airlines do not publish an online prepay option for overweight fees.

What if my bag is both too heavy and too big?

It depends on the airline. American charges only the higher fee plus the bag fee. Southwest charges $200 plus the standard fee. Avelo adds $200. Delta can charge separate weight and size fees.

How can I weigh my suitcase without a luggage scale?

Use a bathroom scale. Weigh yourself, then weigh yourself holding the bag, and subtract the first number from the second. Aim for a pound or two under the limit.

Overweight or Oversized Bag? What Happens Next

The scale at the counter says 52. Or the gate agent points at the sizer and your carry-on will not go in. Your stomach drops. Take a breath: in most cases you have a choice, and the cost is published. This guide walks through what happens in each situation and exactly what each airline charges.

The quick answer

You can usually repack on the spot. If you cannot get the bag under the limit, you pay an extra fee on top of the normal bag fee. Some bags are too heavy or too big to be accepted at all. The fees below are one way, per bag.

Scenario 1: checked bag a few pounds over at the counter

Most US airlines set the standard checked bag limit at 50 pounds and 62 linear inches. Frontier is lower at 40 pounds. Allegiant allows 80 linear inches. Go one pound over and the overweight tier starts.

What the agent will offer

Usually two choices: pay the overweight fee, or step aside and move things out of the bag. On most airlines the first overweight tier is a big jump. Delta charges $100 from 51 to 70 pounds (Delta excess and overweight). Southwest charges $100 plus the standard fee for the same range (Southwest optional charges). American is gentler for a small overage: $30 for over 50 to 53 pounds (American oversize and overweight). United does not publish its overweight fee, and says oversized and overweight bags must be paid at the airport and cannot be prepaid (United prepay page).

How to repack fast

Ask the agent if you can step to the side so the line keeps moving.
Pull the densest things first: shoes, books, toiletries, chargers.
Move them into your personal item or carry-on, if it still fits the cabin limit.
Wear your heaviest jacket and shoes.
Put the bag back on the scale.

Two pounds is often a pair of shoes.

Scenario 2: carry-on fails the sizer at the gate

Basic economy compared with standard fares

On a standard fare that includes a carry-on, a bag that fails the sizer is often checked rather than charged as an extra carry-on, but rules vary, so check your airline's page. On strict fares, it becomes a paid bag. United Basic Economy is the clearest example: a bag that will not fit under the seat costs $75 at the gate (United Basic Economy). On United, larger carry-ons are not offered on most Basic Economy routes at all (United carry-on bags).

Gate check fees that are published

United Basic Economy: $75 at the gate, compared with $50 checked in the lobby. United lists a $25 Basic Economy gate handling charge (United optional charges).
Breeze: $75 per bag if added by airport staff (Breeze bag pricing).
Frontier, Allegiant, Sun Country: gate prices are Not published. Check each airline's page for your flight before you go.

Scenario 3: the bins are full and your bag gets checked

Free gate check and planeside valet

When overhead bins fill up on fares that include a carry-on, agents may check bags at the gate. American says it valets carry-ons larger than the personal item limit on regional planes at no charge, with the bag returned on the jet bridge (American carry-on bags). Other airlines do not publish a single rule, so ask the gate agent. Take out medicine, keys, electronics and anything valuable before you hand the bag over. Our regional jet carry-on guide covers small planes in more detail.

Overweight and oversize fees by airline

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Airline	Standard limit	Overweight fee	Oversize fee	Not accepted	Source
Frontier	40 lb, 62 linear in	41 to 50 lb $75. 51 to 99.99 lb $129 if booked on or after April 4, 2026, $100 if booked before	63 to 110 linear in $75	100 lb or more, over 110 linear in	Frontier bag options
Allegiant	50 lb, 80 linear in	51 to 70 lb add $50. 71 to 100 lb add $75	Over 80 linear in add $75	Over 99 lb	Allegiant fees
Avelo	50 lb, 62 linear in	Over 50 to 70 lb add $100	63 to 80 linear in add $100. Both at once add $200	Over 70 lb, over 80 linear in	Avelo optional services, Avelo checked bags
Breeze	50 lb, 62 linear in	$75 on top of the bag price	$75 on top of the bag price	Over 99 lb, over 80 linear in	Breeze bag pricing
Sun Country	50 lb, 62 linear in	Not published	Not published	Not published	Sun Country booking guide
United	50 lb, 62 linear in	Not published, paid at the airport	Not published, paid at the airport	Not published	United checked bags
American	50 lb, 62 linear in	Over 50 to 53 lb $30. Over 53 to 70 lb $100. Over 70 to 100 lb $200	Over 62 to 65 in $30. Over 65 to 115 in $200	Over 100 lb, over 115 in	American oversize and overweight
Delta	50 lb, 62 linear in	51 to 70 lb $100. 71 to under 100 lb $200	63 to 80 in $200	100 lb or more, over 80 in	Delta excess and overweight
Southwest	50 lb, 62 linear in	51 to 70 lb $100 plus standard fee. 71 to 100 lb $200 plus standard fee	63 to 80 in $200 plus standard fee	Not published	Southwest optional charges
JetBlue	50 lb, 62 linear in	51 to 70 lb $150. 71 to 99 lb $150	63 to 80 in $150	Over 99 lb, over 80 in	JetBlue fees
Alaska	50 lb, 62 linear in	51 to 100 lb $100	63 to 80 in $150. 80 to 115 in $150	Not published	Alaska fees page

Rules for when a bag is over on both, from the airline pages:

American: when a bag is both oversize and overweight, the higher of the two fees applies, plus the checked bag fee.
Delta: a bag can owe three separate fees: one for being an extra bag, one for weight and one for size.
Southwest: a bag that is both oversize and overweight pays $200 plus the standard fee.
Avelo: a bag that is both pays an extra $200.
Alaska: more than one fee may apply to a bag.

Worked examples

A 55 pound first checked bag, one way:

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Airline	Bag fee	Overweight fee	Total
Delta	$45	$100	$145
American, at the airport	$50	$100 (over 53 to 70 lb)	$150
Southwest	$45	$100	$145
Alaska	$35	$100	$135
JetBlue off peak, added early	$45	$150	$195
Avelo, low end	$47	$100	$147
Avelo, high end	$75	$100	$175

A 52 pound bag on American: $50 plus $30 is $80. Moving 2 pounds into a personal item takes it to 50 pounds and saves $30.

Frontier, booked on or after April 4, 2026: a 52 pound bag owes the bag price plus $129. Getting it to 45 pounds drops the overweight fee to $75, so $129 minus $75 saves $54. Getting it to 40 pounds removes the overweight fee and saves the full $129.

A bag 70 inches and 60 pounds on American: the oversize fee is $200 and the overweight fee is $100. American charges only the higher one, so $200 plus the $50 bag fee is $250.

United Basic Economy carry-on that won't fit under the seat: $75 at the gate, compared with $50 checked in the lobby. $75 minus $50 is a $25 penalty for waiting until the gate.

When a bag is over on weight and size at once

This is where costs climb fastest. On American you pay the higher fee once. On Southwest, a bag over on both pays $200 plus the standard fee, so $200 plus $45 is $245 for a first bag. On Delta, weight and size can each add a fee. On Avelo, a bag over on both adds $200. Sports gear often lands here, see our sports equipment fees guide.

Weigh at home: three methods

Luggage scale. Hook it to the handle, lift, and read the number. The easiest and most accurate way.
Bathroom scale, two step. Weigh yourself. Then weigh yourself holding the bag. Subtract the first number from the second.
Bathroom scale, bag alone. Stand a small bag upright on the scale if it does not cover the display.

Aim for a pound or two under the limit, since home scales vary. For carry-on size, use our gate sizer home test. See airline detail on United carry-on size and American carry-on size, and fees on Allegiant, Breeze and United bag fee pages.

FAQ

My bag is 51 pounds. Will they charge me?: On most airlines, yes, if the agent weighs it. The standard limit is 50 pounds on most US airlines and 40 pounds on Frontier. American charges $30 for over 50 to 53 pounds, while Delta charges $100 from 51 to 70 pounds. Moving a pound or two into your carry-on is usually the cheapest fix.
Can I move stuff into my carry-on at the counter?: Yes, as long as your carry-on or personal item still fits the cabin size limit. Step to the side, move the heaviest items, and weigh the bag again.
What happens if my carry-on is too big at the gate?: On fares that include a carry-on, it is often checked, but rules vary by airline. On strict fares you pay. United Basic Economy charges $75 at the gate, compared with $50 in the lobby.
If they gate check my bag because the bins are full, do I pay?: American says it valets larger carry-ons on regional planes at no charge. Other airlines do not publish one rule, so ask the gate agent, and remember strict fares charge for bags that fail the sizer.
Can I prepay an overweight fee online?: Not on United. United says oversized and overweight bags must be paid at the airport. Other airlines do not publish an online prepay option for overweight fees.
What if my bag is both too heavy and too big?: It depends on the airline. American charges only the higher fee plus the bag fee. Southwest charges $200 plus the standard fee. Avelo adds $200. Delta can charge separate weight and size fees.
How can I weigh my suitcase without a luggage scale?: Use a bathroom scale. Weigh yourself, then weigh yourself holding the bag, and subtract the first number from the second. Aim for a pound or two under the limit.

Sources

Disclaimer

Bag rules change. Confirm size, fee, and fare rules on the airline site before you travel. BagRule is a publisher site and does not sell tickets or bags.