Shipping Liquids: Rules to Know for USPS, UPS, and FedEx

By Rob Zaleski
Apr 3, 2019
shipping liquids with USPS FedEx UPS

For the current 2023 USPS rates, visit our USPS 2023 Shipping Rate Changes: Flat Rate, Priority, First Class, w/Tables blog!

Many online sellers, particularly those starting out, may not be fully aware of the rules each carrier has when it comes to shipping liquids. Since shipping rates and guidelines are updated each year, things can become difficult to get right. On top of that, Google seems to think that the only liquid people want to ship is alcohol, so that dominates the search results (by the way, we cover that in this support article). Plus, shipping food with USPS comes with its own set of guidelines that are completely different from liquids.

To help merchants who ship liquids often—vendors like CBD oil, essential oils, makeup and beauty supplies, and more—we did some digging ourselves to help you understand the rules to follow when shipping liquids via USPS, FedEx, and UPS.

Important note around COVID-19

If you are planning to send liquids through the mail like hand sanitizer and disinfectant wipes, please read our full breakdown on how to ship hand sanitizer and other hazardous items via USPS, FedEx, and UPS.

In this article, we break down the regulations for mailing liquids so you can find the best way to ship liquids for your online business. If you are unsure of how to ship liquids, we hope this article serves as your ultimate comparison guide for sending liquids in the mail.

Note: As of October 19, 2022, ShippingEasy now offers the lowest USPSⓇ shipping rates in the industry, and the rates reflected in this blog are prior to this change and may not be accurate. For more information on these new rates, check out our blog!

Rules for FedEx

FedEx does a pretty good job of laying out some of their guidelines for shipping liquids in a step-by-step fashion, with a helpful graphic below. We’ve pulled some of the most important information from the pdf to feature it in one place for you.

Primary watertight inner receptacle

Use watertight containers for liquid specimens with a positive closure such as a screw-on, snap-on, or push-on lid, taped for an additional seal. If you place multiple fragile primary receptacles in a single secondary receptacle, they must be individually wrapped or separated to prevent contact between them.

Absorbent material

Place absorbent material between the primary and secondary receptacles, using enough material to absorb the entire contents of all primary receptacles. Suggested absorbent materials include cellulose wadding, cotton balls, superabsorbent packets, and paper towels.

Secondary watertight inner receptacle

Use a watertight sealed plastic bag, plastic canister, or screw-cap can.

Sturdy outer packaging

Use rigid outer packaging constructed of corrugated fiberboard, wood, metal, plastic, or other equally strong material, including cylinders made of such materials and appropriately sized for the contents. Chipboard or paperboard boxes, paper envelopes, and plastic bags are unacceptable outer packaging. The completed packaging must be of good quality, strong enough to withstand the normal rigors of transportation without loss of contents as a result of vibration, changes in temperature, humidity, or pressure

shipping liquid with FedEx

Note that there are specific labeling and possibly packaging guidelines if you are shipping human/biological specimens using FedEx. FedEx also prohibits containers of liquids with a volume exceeding 8 gallons (32 liters) or 70 lbs. in weight for FedEx Ground and SameDay City.

Good to know :Read about the updated 2021 FedEx shipping rate changes.

Rules for USPS

Nonflammable liquids and nonhazardous liquids can be sent via USPS, if sealed inside a waterproof container. A recently proposed rule change states that mailers must mark the outer container of a mailpiece containing liquid to indicate the nature of the contents, and include orientation arrows. This is regardless of whether the package is deemed “breakable” by the shipper.

If you are shipping liquids in containers greater than 4 oz, you are required to triple pack these containers. This means you need to pad around the original container(s), then surround the original packaging with another sealed, leak-proof container which includes absorbent materials, then have that packing in the rigid packaging noted far above, such as a Priority Mail box, USPS Flat Rate box, or Regional Rate box.

Liquids are also perfect candidates for cubic pricing like ShippingEasy’s Flat Rate Green. This applies to smaller, heavier packages (2 – 20 lbs.). A ShippingEasy customer who sells 6 and 12-packs of vitamin-infused water cut 40% off their shipping budget by switching from FedEx to using Flat Rate Green.

If you ship larger packs of liquid, say, 6 packs or 12 packs, cubic pricing can make your 18 lb. case the same price as a 2 lb. case and save an almost unbelievable amount of money per package.

— Michael Trotzuk, ShippingEasy shipping expert

Remember too, if your package weighs less than 16 oz, you can ship it using First Class Package Service, which allows you to use your own box and is the cheapest method for shipping under 1 lb.

2021 USPS
First Class Pkg
(weight not over)
1 & 2
1 oz$3.01$3.03$3.06$3.12$3.22$3.35$3.49$3.49
2 oz$3.01$3.03$3.06$3.12$3.22$3.35$3.49$3.49
3 oz$3.01$3.03$3.06$3.12$3.22$3.35$3.49$3.49
4 oz$3.01$3.03$3.06$3.12$3.22$3.35$3.49$3.49
5 oz$3.46$3.49$3.51$3.57$3.58$3.69$3.85$3.85
6 oz$3.46$3.49$3.51$3.57$3.58$3.69$3.85$3.85
7 oz$3.46$3.49$3.51$3.57$3.58$3.69$3.85$3.85
8 oz$3.46$3.49$3.51$3.57$3.58$3.69$3.85$3.85
9 oz$4.04$4.09$4.12$4.20$4.38$4.53$4.68$4.68
10 oz$4.04$4.09$4.12$4.20$4.38$4.53$4.68$4.68
11 oz$4.04$4.09$4.12$4.20$4.38$4.53$4.68$4.68
12 oz$4.04$4.09$4.12$4.20$4.38$4.53$4.68$4.68
13 oz$5.19$5.23$5.27$5.42$5.66$5.81$5.98$5.98
14 oz$5.19$5.23$5.27$5.42$5.66$5.81$5.98$5.98
15 oz$5.19$5.23$5.27$5.42$5.66$5.81$5.98$5.98
15.999 oz$5.19$5.23$5.27$5.42$5.66$5.81$5.98$5.98

If you’re shipping liquids in primary containers with less than 4 oz of liquids, you recently dodged a bullet. The USPS was considering enforcing the triple packing rule across the board, meaning companies like essential oils, CBD oils, and beauty supplies would have had to invest in more padding and packaging, driving up the cost of shipping these products. For now, USPS has decided to continue monitoring these items and will not make the rule change at this time.

For more information on shipping speciality items, check out our How to Ship Toiletries blog!

UPS doesn’t do a great job of elucidating their specific rules to shipping liquids. It can be inferred from some short mentions on their website that their rules resemble those of FedEx pretty closely. If there’s any uncertainty, it’s always best to reach out to your UPS rep for clarity and ensure your packages arrive as they should.

Once you know the rules regarding how to ship liquids, you can determine the best way to ship liquids for your business. We can help you automate your shipping processes and have a platform that chooses the right shipping methods automatically for every order.

Looking for the best shipping software for small businesses? Start a 30-day trial of ShippingEasy today!

Links used to help inform this article:

New call-to-action

The following two tabs change content below.

Rob Zaleski

Head of Brand at ShippingEasy
I'm a digital content and social media nerd with a passion for telling stories, helping connect people, and finding joy in the details.

Latest posts by Rob Zaleski (see all)