Take it from me, because I did it wrong: we went to Mexico with a whole sleeve of diapers when our toddler was 20 months old. By day 5 of the 7-day trip, we ran out. So we bought more, in the smallest denomination of diapers: a pack of 40.

My “diaper math” had been, pack diapers, use them all, and come back with extra space in my suitcase.

Instead, I came back with a 90% full diaper sleeve in my suitcase (because we couldn’t throw out diapers, or just leave them in Mexico!) and saved no space at all. My diaper math had failed.

In this guide, I’ll help you figure out how many diapers to take on YOUR trip, and how to do baby diaper packing math like a pro.

Thank you to Coterie for partnering with me on this “diaper math” guide for parents who travel!

Key takeaways: Travel diaper math for parents

  • I’ll recommend the best travel diaper (Coterie), and why the type of diaper you take traveling matters.
  • See below for my diaper math formula to keep handy.
  • My best pro tip: Take 1 diaper per every 2 hours of travel, on travel days. I learned this standard metric from daycare, where babies are changed every 2 hrs (this number grows to ~3 hrs over age 1).
  • If your trip is under 4 days, you may pack enough diapers for the whole trip to avoid shopping for more diapers.
  • If your trip is 4+ days, I suggest packing diapers for the first 24 hours of travel, and then shop for more diapers. (I’ve done this!)
  • If you’re road tripping to a place where there may not be supermarkets nearby (i.e. camping, forest cabins, small islands), bring enough diapers for the ENTIRE trip, packed with you.
  • If road tripping, you can be much more liberal with diaper packing when compared to flying.

Why diaper math?

It would seem like the silliest thing to explain to a non-parent, but to baby parents, we know: calculating how many diapers we need is a crucial skill on travel days and when packing for trips.

But why? Well, it mostly comes down to space in our luggage, especially if flying. (If you’re road tripping, diaper math matters mostly for having diapers available in the car for mid-ride changing.)

And if you’re flying with a baby, you have to have plenty of diapers at the ready, but also, not too many, or they’ll take up your whole diaper bag.

So where’s the happy medium? Enter “Diaper Math” for parents flying with babies and toddlers. I’m going to outline a few situations for counting your travel day diapers or your number of vacation diapers, as well as the type of diapers I take.

Helpful Tip

I did my fair share of reading across the Internet about so-called diaper math, and I think what a lot of sources fail to comment on is the fact that trips of different lengths allow you to buy diapers when you get there; OR, the trip is so short that you might as well not spend time shopping. Let’s dive deeper, parent friends.

Which type of travel diapers to take traveling

I outlined this in my guide to travel day diapers, and the same logic checks out for calculating how many diapers to take on a vacation.

To me, it’s more worthwhile to take a good quality and highly-absorbent diaper I can count on, rather than countless (or just a high number of) bad quality diapers that are going to rip, tear, lead to blowouts or leaks or feel papery/plasticky on my baby during long hours road tripping or flying.

So we take Coterie diapers. They’re what I take in my travel day diaper bag, what I pack for long car rides, a must-have in my toddler’s diaper bag and definitely the diaper I take on a plane. Coterie diapers, with their super-soft ribbed texture on the outside, are the most absorbent, with 12-hour leak protection, and they’re the real-world performance I’m looking for on high-stakes travel days.

Plus, taking them along for the start of my trip means that I’ve automatically packed nighttime diapers, even if I forget them on my packing list. That’s because Coterie diapers are designed to be a single diaper that performs during both day and night.

I used to get stressed about diaper leaks, but the reliability with Coterie diapers means peace of mind It’s highly likely that I won’t have to use that extra T-shirt I pack for myself in my airplane diaper bag for unexpected blowouts.

Helpful Tip

Try Coterie diapers here and stock up for your next trip. Use the Coterie discount code HALFHALFHOME at checkout for 15% off (new customer subscription purchases) with a min. spend of $40, and read our full Coterie review here.

If you need to pack light with a baby or a toddler, less is more, when it comes to diapers that really work.

Diaper math formula

There’s some quick-hand math you can do to estimate the diaper count for travel days.

  • By now, you probably know your baby’s # of changes per day (newborns are 8-10 changes per day, while toddlers over 15 months might be 4 changes per day. It can vary - Coterie makes a helpful guide to count diapers per day, by age!)
  • (# hours spent in transit / 2) + 3 spares = your travel day diaper number (*This is for babies under 12 months, on average)
  • (# hours spent in transit / 3) + 2 spares = your travel day diaper number (*This is for toddlers above 12 months, on average)
  • This means you’ll have a diaper for every 2-3 hours, plus spares, in case of tummy troubles or losing a diaper somehow.

Now, some quick-hand math to estimate diaper needs for days on the ground during vacation (at your destination). Note: This assumes you’ll shop within a day of landing, so 1 travel day + 1 day on the ground.

  • Take your baby’s travel day diaper count.
  • Now, add their 24-hour diaper needs (# changes per day, plus 3 spares).
  • Add your overnight diaper, x 1.5 (or more) to account for however many times your child wakes up during the night for a change (Then read, How to get your baby to sleep on vacation)
  • This number gets you to how many diapers to pack, before you shop when you get to your destination.

Notes: First, spare diapers should go into the total count. Second, use the travel day formula for flight days or days spent in the car.

This formula should help avoid over-packing!

Diaper packing math: how many diapers to pack for a road trip?

If you’re packing for a road trip with your baby, here are two things to consider.

  1. If there are going to be diapers at your destination
  2. If there are NOT going to be ways to shop for diapers at your destination

Why am I even telling you this? We once took a roadtrip to Upstate New York, and stayed in a woodsy cabin with our baby. Were we crazy? Maybe yes! Did we take diapers for the ENTIRE trip with us? Yes, we did.

Did we drive home with a single diaper left in my diaper bag? Also yes. Let’s say I calculated 99% correctly, as we almost came home with net-zero diapers. And survived! So in short:

  1. Diapers at your destination: pack enough diapers for the car ride (1 diaper for every 2 hours), and diapers for the first 24 hours of your stay. Assume that you will shop or visit a supermarket/pharmacy within 24 hours of arriving, whether that night, or in the morning.
  2. NO diapers at destination: pack enough diapers for the car ride, and back. Then, pack enough diapers for each day of the trip, including an overnight diaper worked in. This varies for babies of different ages, but I will say I’ve had some surprises on trips and have had to change much more frequently than at home. BE LIBERAL in your calculations.
Helpful Tip

My personal tip is to stash even more diapers in the car: put them in a diaper fanny, and leave that on the floor, or make a “backup diaper” Ziplock bag or travel pouch that you leave in a car door. I’ve had to go into these extra stashes, all because unexpected situations came upon us during travel with a baby.

Diaper packing math: how many diapers to take on short vacations (flying)

We’ve done both, the short flying trips, and longer flying trips. As you read above, I calculated ALMOST correctly for the Mexico trip, but instead, got screwed by flying back with as many diapers as I had arrived with. That still makes me chuckle.

If you are taking a SHORT trip (let’s take for example our trip to Halifax, Nova Scotia, for four days, with our 8-month-old baby).

Pack for the plane and your travel day

Count your diapers: 1 diaper for every 2 hours of travel time.

Our flight was only 2 hours, but we had 2 hours in the airport beforehand, and I knew I’d do a change at the gate. It’s also good to have 1 more spare in case of another last-minute #2. Leave 1 more diaper for changing upon arrival, if there is a stinker.

Helpful Tip

If you have not yet seen my guide on How to Change a Diaper on a Plane, bookmark it and keep it handy before flight day if it is your first time diapering while flying.

Pack for each day of the trip (under 4 days of travel)

If less than 4 days of travel, you have the option to really take enough diapers with you, and then come back with that space empty in your luggage. THat’s the most satisfying thing!

Example:

Your baby is 8 months and you’re going to Mexico City for total 4 days, but two bookend days of flying. You have 2 full days to explore the city.

  • Flying days: 1-2 diapers for airport, 3 diapers for flight (5.5-hr flight), 1 diaper for landing. This is liberal, just in case of things you don’t expect. It is better to have more diapers than fewer - can you imagine running out?!
  • Two days on the ground: at 8 months, your baby probably needs 6-8 diapers a day. If you have a preferred overnight diaper, take 2 per night (in case of middle-of-night wake-ups and re-diapering). If you take Coterie diapers, no need to pack overnights!

Diaper packing math: how many diapers to take on long vacations (flying)

Let’s picture that your flight is way longer, and your time for vacation is way longer, too. I’ll say your flight is 12 hours to Tokyo, and you have two weeks there.

  • In this case, I’d pack diapers for the plane with a stretch of 6 or 8 hours as some overnight sleep, with the baby in a bassinet or car seat.
  • Depending on your baby’s age, go with a baseline of 1 diaper for every 2 hours, and then feel free to subtract 3, for that period of night sleep.
Helpful Tip

if you take a highly-absorbent diaper like Coterie, you can eliminate a whole bunch of fuss over feeling “wet,” and really only need to change for dirty diapers, rather than just wet. This is if you want to pack a minimal amount of diapers and do less changing on the plane.

For a long vacation, I would 100% pack diapers for travel day and the first 24 hours on the ground, and then shop for diapers at a local grocery store or supermarket, or pharmacy.

If you are very particular about diapers, you can sling along more from home, in checked luggage, and in some other creative spaces. I’ll talk about this in “Diaper packing tips” below.

For the trip home, there are a few things you can do…

  • Calculate with the method above, the diapers needed for the last 24 hours on the ground plus travel day. Include back-up diapers for time spent in unforeseen delays.
  • If you have extra diapers, you can either take them home with you, or give them away if they don’t fit in your luggage.
  • How would you give diapers away? You can leave them with a hotel concierge, and request that they go to any of the staff who may have babies at home. You could leave them at your Airbnb, and leave the host a note that they can be given to any friends/family of theirs, or kept in some type of ‘backup product’ trove for future guests. (These are just some creative ideas I had!)

The goal is to not come home with a ton of diapers in your luggage, because of course, luggage is somehow more stuffed on the way back than on the way in.

Diaper packing tips that worked for us!

As a bonus, here are some diaper packing tips that have worked for us.

Pack diapers compressed in the sleeve them come in

The best way to compress diapers is to remove the air out of them, because they are fluffy.

You can pack diapers in original packaging. This is the smartest. If you don’t want to overpack on diapers though, you can also…

  • Compress diapers into a Ziplock bag and squeeze out the air.
  • Put them into a packing cube (we recommend a few packing cubes that compress)
  • Use a compression bag (these vacuum storage bags have a cordless pump), and you may like it for other stuff you pack, too

Stash diapers into your car seat

This is one of the favorite hacks I’ve learned - put a sleeve of diapers into your car seat, IF you are checking it as luggage. And we always have, when traveling with a baby or very young toddler.

Here’s a photo of how I put an entire sleeve of diapers into our UPPAbaby Mesa car seat and then sent it off for bag check.

Split up diapers in luggage

In addition to your diaper bag and carry-on, you can also put diapers throughout your checked luggage, wherever they fit into your suitcase. You can also use diapers to pad things like pointy shoes, large jewelry, oddly shaped items or fragile/breakable souvenirs.

Thanks again to Coterie for partnering with us for this travel diaper guide - you can stock up for your trip at the Coterie website with our discount code HALFHALFHOME for 15% off (new customer subscription purchases) with a min. spend of $40.

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