You’re standing in the aisle at Sephora or staring at a travel-sized sunscreen on Amazon, and you see it: 1.7 oz. It’s an oddly specific number. Not quite two ounces, definitely more than one. You might be wondering if it’s going to last a week or a month, or if the TSA agent is going to toss it into that sad clear bin of confiscated liquids.
Honestly, the "how big is 1.7 oz" question is basically the most common riddle in the beauty and fragrance world. It’s the industry standard for a reason, but that doesn't make it any less confusing when you’re trying to visualize a liquid volume in your head.
Let's get the math out of the way first because precision matters. 1.7 ounces is exactly 50 milliliters (ml).
If you look at the bottom of almost any high-end perfume or a standard jar of "luxe" face cream, you’ll see that 50ml stamp. It is the "Goldilocks" size of the retail world. Why? Because 50ml is exactly half of the 100ml maximum allowed by the TSA for carry-on luggage. It’s a safe bet for travelers, and it’s a profitable volume for brands.
Visualizing 1.7 oz in the Real World
If you don't have a graduated cylinder in your kitchen—and let's be real, most people don't—you need some better reference points.
Think about a standard golf ball. 1.7 ounces of liquid occupies roughly the same amount of space as a golf ball, maybe just a tiny bit more. If you were to pour 1.7 oz into a standard shot glass, it would fill it right to the brim and then some, as most shot glasses are 1.5 ounces. You’d have a messy spill on your hands.
✨ Don't miss: Green Emerald Day Massage: Why Your Body Actually Needs This Specific Therapy
In terms of food, it's about three and a half tablespoons. Imagine three tablespoons of olive oil. It feels like a decent amount for a salad, but it’s a tiny amount if you’re trying to hydrate your skin for three months straight.
The TSA Rule: Is 1.7 oz Travel Safe?
Absolutely. You’ve probably heard of the 3-1-1 rule. The TSA (Transportation Security Administration) and international bodies like the EASA allow containers that are 3.4 ounces (100ml) or less.
Since 1.7 oz is exactly half of that limit, it’s one of the best sizes for flying. You can fit more of these in your quart-sized bag than those bulky 3.4 oz bottles. If you’re a minimalist traveler, 1.7 oz is your best friend. It’s small enough to pass security but large enough that you won't run out of shampoo on day three of a trip to Cabo.
How Long Does 1.7 oz Actually Last?
This is where things get tricky because it depends entirely on what is inside the bottle. A 1.7 oz bottle of perfume is a massive amount of liquid compared to 1.7 oz of body lotion.
Fragrance and Perfume
If you have a 1.7 oz (50ml) bottle of Eau de Parfum, you’re looking at roughly 500 to 700 sprays. If you’re a "two-spray-a-day" kind of person, that bottle is going to last you nearly a year. Even if you’re heavy-handed and do four sprays every morning, you’ve still got five or six months of daily use. This is why 1.7 oz is often the "best value" size for perfume; it’s cheaper than the 3.4 oz bottle but still lasts long enough to justify the $100+ price tag.
🔗 Read more: The Recipe Marble Pound Cake Secrets Professional Bakers Don't Usually Share
Skincare and Face Creams
Now, let’s talk about that expensive night cream. Most standard moisturizers come in—you guessed it—1.7 oz jars. If you use a pea-sized amount (which is what dermatologists like Dr. Shereene Idriss usually recommend), that jar should last you about 60 to 90 days. If you’re slathering it down your neck and chest (which you should be!), you’re probably looking at 45 days.
Sunscreen
Here is the shocker. 1.7 oz of sunscreen is almost nothing. According to the American Academy of Dermatology, you’re supposed to use about an ounce to cover your entire body for one application. That means a 1.7 oz tube of sunscreen provides less than two full-body applications. If you're only using it for your face, it’ll last about a month. But for a beach day? 1.7 oz is basically a single-use item.
[Image showing 1.7 oz of liquid poured into a standard measuring spoon]
Why Do Brands Love 1.7 oz So Much?
It’s all about the "price floor." Brands know that 1 oz (30ml) often feels too small for a primary product, like a daily moisturizer. It feels like a "sample." On the flip side, 3.4 oz (100ml) can make the price jump from $50 to $90, which scares people off.
The 1.7 oz / 50ml size sits right in that psychological sweet spot. It feels substantial in your hand. It has enough "heft" to feel like a premium purchase.
💡 You might also like: Why the Man Black Hair Blue Eyes Combo is So Rare (and the Genetics Behind It)
The Density Trap: Ounces vs. Fluid Ounces
We have to get nerdy for a second. There is a huge difference between weight ounces and fluid ounces.
- Fluid Ounces (fl oz): Measures volume (how much space it takes up).
- Net Weight Ounces (oz): Measures how much it weighs on a scale.
If you have 1.7 fluid ounces of water, it weighs about 1.7 ounces. But if you have 1.7 fluid ounces of a heavy, dense hair wax, it might actually weigh more than 1.7 ounces on a scale. Most beauty products use fluid ounces for liquids and weight ounces for solids or thick pastes. Check the label carefully. If it says "Net Wt. 1.7 oz," that's weight. If it says "1.7 fl oz," that's volume. Usually, for things like face creams, they are close enough that you won't notice, but for airy products like shaving cream or mousse, 1.7 oz of weight is a much larger container than 1.7 oz of volume.
Comparing 1.7 oz to Other Common Sizes
Sometimes you just need to see the lineup.
- 1 oz (30ml): The standard "small" size. Often used for serums or oils. It’s about the size of a large walnut.
- 1.7 oz (50ml): The "medium" or "standard" size. The golf ball.
- 3.4 oz (100ml): The "large" or "max travel" size. Roughly the size of a baseball or a juice box.
- 8 oz (240ml): A standard cup. Think of a small bottle of water or a bottle of drugstore body lotion.
Practical Takeaways for Your Next Purchase
Don't let the packaging fool you. Many brands use "double-walled" jars where the 1.7 oz of cream is hidden inside a much larger-looking plastic container. Always look for the number on the back of the box, not the size of the box itself.
If you’re buying perfume and it's your "signature scent," the 1.7 oz is usually a bad deal compared to the 3.4 oz. However, if you like to rotate scents, 1.7 oz is the way to go because perfume does expire and lose its top notes after about 3-5 years.
For skincare, 1.7 oz is the perfect "trial" period. It takes about 28 days for your skin cells to turn over, meaning you need at least a month to see if a product is actually working. A 1.7 oz jar gives you enough product to get through two full skin cycles, which is exactly how long you should test a product before deciding if it’s a "holy grail" or a "total fail."
Next Steps for Accuracy
- Check your current daily moisturizer; it’s likely 1.7 oz. Mark the date you opened it on the bottom with a Sharpie.
- Note when you hit the bottom of the jar. If it's less than 30 days, you're using too much product. If it's more than 90 days, you're likely not using enough to get the advertised benefits.
- For travel, don't bother decanting 1.7 oz products into smaller bottles; they are already the perfect size for a 10-day trip.