How to Choose a Halloween Costume in St. Louis
Revised October 29, 2026
How to know what size Halloween costume to get?
Ignore the S/M/L letter and read the measurement chart printed on the bag. Measure chest, waist, and height with a soft tape, then match those numbers to the chart for that specific costume. When you land between two sizes, go up. You can pin, belt, or hem a costume down, but you can’t make it bigger.
Keep reading ↓The bag says medium. Your kid is a medium. Then the thing goes on and the sleeves quit at his elbows while the pant legs puddle over his shoes. It’s the night before Halloween in St. Peters, the aisle is down to one clown and a pair of lonely bananas, and you’re holding a roll of tape wondering how this happened. Again.
It happens to almost everyone. Packaged costumes get sized by people who’ve never met your child, cut from fabric thinner than the bag it ships in, and photographed on a model who had a stylist and a fan blowing her hair. The letter on the front is a suggestion, not a promise. Adults get burned the same way, just with more money on the line and fewer excuses.
So here’s the adjuster’s version of costume shopping. What to measure before you buy. When to rent instead. Why the costume never looks like the photo, and the cheap fixes that close most of that gap. What survives a St. Louis October, which runs warm at 4pm and cold by 8. And which questions to ask a costume shop before you drive across the metro to visit it.
How to know what size Halloween costume to get?
Ignore the S/M/L letter and read the measurement chart printed on the bag. Measure chest, waist, and height with a soft tape, then match those numbers to the chart for that specific costume. When you land between two sizes, go up. You can pin, belt, or hem a costume down, but you can’t make it bigger.
There’s no industry standard behind those letters. One manufacturer’s medium fits like another’s small, and kids’ costumes are often labeled by age range, which tells you nothing about a tall seven-year-old or a small ten-year-old. The chart on the back of the bag, or on the product page, is the only number that came from the actual pattern. Trust that. Ignore the rest.
Measuring takes two minutes. Chest: wrap a soft tape around the fullest part, over a t-shirt, not squeezing. Waist: the natural line, roughly where a belt sits. Height: barefoot, back against a wall, book flat on the head. Write the three numbers in your phone. You’ll need them again next year, and probably next week when the kid switches from pirate to astronaut.
Then compare, and be honest about it. If the chest number sits at the top edge of the medium range, buy the large. A costume that’s a little roomy gets a belt and a couple of safety pins. A costume that’s too tight gets a split seam halfway down the block and a very short night. If the shop lets you try it on, do that instead of guessing. It beats every chart.
Should you buy, rent, or build it?
Buy for kids and for anything you’ll wear more than once. Rent when it’s a single night and you want the piece to look real: a period gown, a full-body character suit, anything with structure. Build when you have time, a base garment already in the closet, and a look that’s more about the idea than the fabric.
When renting makes sense
Rental costumes come from a different world than bagged ones. They’re made to be worn many times, so the seams hold, the fabric has weight, and the fit gets adjusted by someone who does this all day. For an adult party where you actually want to look like the character, a rental usually lands closer to the photo in your head than anything in a plastic bag. The trade-off is you can’t spill on it, and you have to bring it back.
When buying is the smarter call
Kids wear costumes hard. They eat in them, run in them, and wear them to school, to the grocery store, and to bed if you let them. A rental can’t survive that, and a rental shop won’t want it to. Buy the kid costume. Same rule for anything you’ll pull out again: a decent cape, a good hat, a lab coat. Repeat use turns a purchase into a bargain.
When building wins
Building doesn’t mean sewing from a pattern. It means starting from clothes you own and adding the parts that sell the idea. Black jeans, a striped shirt, and a knit cap is a burglar. A trench coat and a fedora is a detective. Most homemade costumes that work are one base garment, one strong accessory, and a little makeup. They also fit, because they’re your clothes.
One honest caveat from experience: building takes longer than you think, every single time. If it’s the 28th and you have a full week of work ahead, buy the bag and spend your free evening fixing it instead.
Why does the costume never look like the bag photo?
Because the photo was staged. The model was picked to fit the sample, a stylist pinned the back, the plastic sword was swapped for a real prop, and a lighting rig hid every wrinkle. What’s in the bag is the garment, the cheapest version of the accessories, and nothing else. The gap isn’t your fault. It’s the business model.
The good news is that most of the gap closes with a few moves that cost less than a second costume. Here’s what actually moves the needle, in rough order of impact.
- Fix the fit first. Belt it, pin it, or hem it with iron-on tape. Most of what reads as “this looks cheap” is really “this doesn’t fit.”
- Wear real shoes. The photo model wore boots; the bag gave you nothing. Your own boots, sneakers, or dress shoes beat any shoe cover ever made.
- Swap the plastic accessories. The included hat, belt, and weapon are the weakest parts. A thrift-store belt or a real hat changes the whole read.
- Add makeup. Even simple face paint, a drawn scar, or dark eyes makes a cheap costume look intentional.
- Weather it. For pirates, zombies, scarecrows, and anything “old,” soak the fabric in strong cooled tea for a dingy tint, then rough the edges with sandpaper. Test a hidden spot first.
Weathering deserves a warning. Tea stains are permanent, and sandpaper doesn’t un-fray. Do it on a costume you own, never on a rental, and never on the night of. Give it a full day to dry so nobody ends up with brown streaks on a couch in Creve Coeur.
What makes a costume actually work in a St. Louis October?
Layers, real shoes, and something reflective. A St. Louis Halloween can start warm enough for shorts at the school parade and drop into jacket weather by the time the porch lights go out, so the costume needs to work over a base layer and under a coat without falling apart. If it only works at one temperature, it only works for an hour.
Dress for the 8pm version of the night
Plan the costume around the cold hour, not the warm one. A thin base layer underneath, thermal or long-sleeve, disappears under almost anything. For small kids, size the costume to fit over a hoodie so nobody has to choose between warm and in character. Adults heading to a party can stash a jacket in the car, but a kid on a sidewalk in Granite City can’t. Build the warmth in.
Shoes you can walk a mile in
Trick-or-treating is a mile or two of walking, plus stairs, plus one fall on a wet leaf. Costume shoe covers slide, tear, and come off in the first block. Put the kid in sneakers and let the costume be the costume. Adults, same story. If your character needs heels, bring flats for the walk from the car.
Visibility for kids
Dark costumes on dark streets are the real safety issue, not the fake blood. A strip of reflective tape on the back, a glow stick on a lanyard, or a small clip light on the candy bag fixes most of it. Masks that block side vision are a problem on stairs and at curbs. Face paint sees better than a mask every time, and it doesn’t get ditched in someone’s yard by the fourth house.
Lots of families make a whole night of it, with a trunk-or-treat or a haunted walk before the neighborhood loop. If you’re planning that, the St. Louis Halloween events guide covers what’s worth the drive. Just remember that an outdoor event at 6pm and a sidewalk at 8pm need the same jacket.
How do you pick a costume for a kid who changes their mind weekly?
Set a decision date and buy pieces that convert. A kid who’s been a dinosaur, a firefighter, and a ghost in the same month isn’t fickle, they’re five. Don’t buy on the first ask. Wait until the pick survives two weekends, then shop, and lean toward costumes where the base works for more than one idea.
Convertible pieces save you. A black sweatsuit is a cat, a ninja, a spider, or a bat depending on what you clip to it. A brown one is a bear, a dog, a monkey, or a gingerbread man. Buy the accessories, not the whole outfit, and the mid-October pivot costs you a pair of ears instead of a second costume.
Do the comfort test at home. Put the whole thing on, shoes and all, and have the kid wear it for twenty minutes while doing normal kid stuff. Scratchy neck? Mask fogging? Cape catching under feet? You want to find that out on a Tuesday, not at the first porch. What they say they want and what they’ll actually keep on are two different costumes.
Give them ownership somewhere. Let them pick the accessory or the face paint color, and the costume becomes theirs, which is the strongest defense against a meltdown on the 31st. And if the plan includes dinner out first, the guide to eating out with kids in St. Louis has the pre-trick-or-treat strategy covered.
What should you skip entirely?
Skip anything that treats another group’s culture as a costume, anything built on a real tragedy or a recent crime, and anything you physically can’t see or walk in while herding kids. Those are the three hard lines. Everything else is taste, and taste is negotiable.
The overdone list changes a little each year but the shape stays the same: whatever the biggest movie was, whatever the biggest show was, a witch, a vampire, a cat, and a generic zombie. There’s nothing wrong with any of them. You’ll just see six more at the party. If you want to wear one anyway, twist it. A vampire who’s clearly a dentist. A witch on her way to a job interview. A zombie in a full tuxedo, tea-stained. The twist is what people remember, and it usually costs one accessory.
Then there’s the practical list. Full-face masks with kids in tow. Long capes on stairs. Anything with a trailing hem you’ll drag through wet leaves. Inflatable suits, which are hilarious for ten minutes and a sauna after that. And anything that reads as a real uniform from a distance, because at night, on a doorstep, that confusion isn’t funny to the person opening the door.
How do you choose a costume shop worth the drive?
Shortlist two or three shops, call each one, and tell them exactly what you want and expect. Then compare that against what they’re actually set up to deliver. The gap between the two is the signal. A shop that’s honest about a gap is worth more than one that says yes to everything.
Here’s what to ask, in plain words:
- Can we try it on before we buy? Where, and is there a mirror?
- What’s the return or exchange window, and does it close before Halloween?
- If we rent, does the price include cleaning, and what happens if it comes back with a stain?
- What sizes do you actually have in the back, not just on the rack?
- Can you adjust the fit, or point us to someone who can?
Listen for specifics. “Sure, we have all sizes” means nothing. “We’ve got that one in medium and large, the small sold out last week” means they looked. A shop that knows its stock will save you a drive from St. Clair for a costume that isn’t there. The same interview frame works for a lot of one-night purchases; our post on what to ask before booking party rentals in St. Louis uses it for tables and tents.
Early for selection, late for clearance
Timing is the other half of choosing a shop. Early October has the full range of sizes, and the staff has time to help. The last week has clearance pricing, empty racks, and a line. If you know what you want and it’s a common size, shopping late can pay off. If your kid sits at the edge of a size range or wants something specific, go early and pay for the selection.
Pop-up seasonal stores and year-round costume shops play different games. The pop-up has volume and price. The year-round shop has rentals, fitting help, and someone who’s seen your exact problem before. In our experience the year-round shop earns its keep on adult costumes and anything that has to look right up close, while the pop-up wins on kids’ costumes you’ll retire in November.
Hungry after the last porch light goes dark? Here’s what makes a burger worth it.
Ready to find the right fit? Browse costume shops and rentals across the St. Louis metro on St Louis Near Me Directory, then call two of them with your measurements before you drive anywhere.
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Frequently asked questions
Should you size up in costumes?
Yes, when you’re between sizes or at the top of a range. Packaged costumes run inconsistent and often small, and a roomy costume is easy to belt, pin, or hem. A tight one splits. The one exception is a very young child in a long costume, where sizing up creates a tripping hem. Hem it, or pick the smaller size and skip the base layer.
What to do if your Halloween costume is too big?
Take it in where nobody looks. Safety pins at the back seam, a belt at the waist, and iron-on hem tape at the cuffs and hem fix most of it in fifteen minutes. Layer a hoodie or thermal underneath to fill out the chest. For a kid, roll the sleeves and pin them from the inside so the pins never touch skin.
How to save money on Halloween costumes?
Build from clothes you already own and spend on one strong accessory. Buy convertible basics like a plain sweatsuit that works for several characters. Shop clearance in the last week if your size is common. Borrow or swap with other families, since kids outgrow costumes after one wear. Skip the shoe covers and use real shoes you already have.
How to make a Halloween costume look better?
Fix the fit first, since most of what reads as cheap is really a bad fit. Wear real shoes instead of covers. Replace the included plastic belt, hat, or weapon with a thrifted real one. Add face paint or a drawn scar. For pirates, zombies, and scarecrows, tea-stain the fabric and rough the edges with sandpaper.
What is the most overused Halloween costume?
Whatever the biggest movie or show of the year was, followed by the evergreens: witch, vampire, cat, and generic zombie. You’ll see all of them at any party. If you love one anyway, twist it with a job, a mood, or an era. A vampire dentist or a witch at a job interview gets remembered. A plain vampire doesn’t.
What not to dress up as for Halloween?
Anything that turns another group’s culture into a costume, anything based on a real tragedy or a recent crime, and anything that reads as a real uniform on a dark doorstep. Practically, skip full-face masks and long capes if you’re walking kids, and skip anything you can’t see, walk, or climb stairs in.
Why are Halloween costumes so expensive now?
A few things stack up. Licensed characters carry a licensing fee before the fabric is even cut. Costumes are seasonal, so a retailer has a few weeks to sell what it had to ship and store for months. Materials and shipping have gotten pricier across the board. And a packaged costume sells once, with no repeat-customer discount built in. Rentals and homemade builds sidestep most of that.
When is the best time to buy a Halloween costume?
Early October if you need a specific size, a specific character, or help with fit, because that’s when the shelves and the staff are both full. The last week before Halloween if your size is common and you want clearance pricing. Reserve rentals early either way, since the good pieces go first.
Written by a dedicated team of St. Louis locals who live, work, and play right here in the St. Louis metro. Founder Lane Forman and team are committed to building the region’s most trusted directory by verifying listings and connecting local businesses with loyal customers across Missouri and Illinois.