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Zojirushi SW-KA40 vs SW-EAE50: Which Food Jar to Buy?

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Short answer: Zojirushi lists both at 147°F after 6 hours, even though the SW-KA40 holds 3 oz less (14 vs 17 oz). The KA40 gets there with its newer Therma Chamber lid, and it also adds a leak-proof one-piece stopper, a pressure-relieving lid, and a wider 2-7/8-inch opening. The SW-EAE50 is the pick if you just want the bigger portion.

How we compare: every spec in this article comes from official manufacturer specifications and manuals (starting with Zojirushi’s official product page), all listed under Sources below. We don’t run hands-on tests, and if a spec isn’t published, we say so. Last updated: October 2026.

Check price: Zojirushi SW-KA40
Check price: Zojirushi SW-EAE50

I live in Japan. Zojirushi calls the SW-KA series the food jar line “with the highest heat retention in Zojirushi history.” Comparing it with the older SW-EAE50 shows what that means in practice.

I haven’t tested these side by side. Everything below comes from the manufacturers’ official product pages, linked at the end. If a spec isn’t published, I say so instead of guessing.

Quick Comparison Table

Spec SW-KA40 SW-EAE50
Capacity 14 oz / 0.40 L 17 oz / 0.5 L
Dimensions (W x D x H) 3-7/8 x 3-7/8 x 5 in 3-5/8 x 3-5/8 x 6 in
Weight 0 lb 12 oz (0.12) 0 lb 11 oz (0.11)
Heat after 6 hours* 147°F 147°F
Cold after 6 hours* 48°F 50°F
Opening 2-7/8 in 2-1/2 in
Lid Therma Chamber lid, one-piece stopper with integrated gasket, pressure-relief Tight-fitted lid with gasket
Leak-proof claim Yes (when used per manual) Minimizes leaks
Colors Ice Gray, Matte Green, Beige 5 colors
Made in Thailand Thailand

*Zojirushi rates heat retention with 203°F (95°C) water in a 68°F (20°C) room, and cold retention with 40°F (4°C) water in the same room.

Key differences at a glance

  • Heat retention: The SW-KA40 matches the larger SW-EAE50 at 147°F after 6 hours despite holding less (14 oz vs 17 oz).
  • Lid: The SW-KA40 has a leak-proof one-piece stopper with pressure relief, while the SW-EAE50’s gasket lid is described as minimizing leaks.
  • Shape: The SW-KA40 is shorter and wider (3-7/8 x 5 in), while the SW-EAE50 is narrower and 1 inch taller.
  • What stays the same: Both use 18/8 stainless with a SlickSteel finish, are made in Thailand, and carry a five-year thermal warranty in the US and Canada.

The 3 Differences That Matter

1. Same heat rating, less volume

Smaller jars normally lose heat faster, yet the KA40 matches the larger EAE50 at 147°F. That’s the Therma Chamber lid, which Zojirushi says uses small internal chambers to cut heat loss.

2. Leak-proof and pressure relief

Zojirushi calls the KA40’s one-piece stopper leak-proof when used per the manual, and says the lid relieves pressure from hot food as it opens. The EAE50’s lid is described as minimizing leaks.

3. Shape

The KA40 is shorter and wider (3-7/8 in wide, 5 in tall). The EAE50 is narrower and 1 inch taller. The KA40’s 2-7/8-inch mouth makes it easier to eat from and clean.

What’s the same

Both use 18/8 stainless with a SlickSteel finish, are made in Thailand, and have Zojirushi’s five-year thermal insulation warranty in the US and Canada.

Who Should Buy Which?

Choose the SW-KA40 if you:

  • Want the leak-proof stopper for a bag
  • Want the widest opening
  • Are fine with 14 oz

Choose the SW-EAE50 if you:

  • Need the extra 3 oz
  • Want a slimmer jar
  • Want more color choices

The SW-KA at Home in Japan

The SW-KA is also sold in Japan, where Zojirushi launched the series in 2022 as a soup jar (スープジャー). On Zojirushi Japan’s site, the 400 mL SW-KA40 comes in ice gray, matte green and beige, has a roughly 7 cm mouth, and is rated at 64 °C or higher after 6 hours. Japanese marketing focuses on the “seamless” lid, where the stopper and gasket are one piece, and on a mouth wide enough to fill with a ladle. Colors and packaging can differ from US listings, so check the US listing.

Japanese reviewers on Rakuten and Kakaku.com often say the SW-KA keeps soup warm until lunch, especially if the jar is preheated with hot water, and like its wide mouth and few parts; one recurring gripe is that the large lid is hard to open one-handed. (Third-party reviews, not our own testing.)

Weighing sizes within one line instead? See SW-KA40 vs SW-KA52 or SW-EAE35 vs SW-EAE50.

SW-KA40 vs SW-EAE50: Frequently Asked Questions

Which is newer?

The SW-KA series, which Zojirushi describes as having its highest food-jar heat retention to date.

Do both keep food at 147°F after 6 hours?

Yes, per Zojirushi’s ratings with 203°F water.

Which is easier to clean?

The SW-KA40 has a wider 2-7/8-inch opening and a one-piece stopper with an integrated gasket.

Is the SW-KA40 leak-proof?

Zojirushi says it is when used according to the instruction manual.

Check current listings

Prices and colors change often, so check the current listing before buying.

Check price: Zojirushi SW-KA40
Check price: Zojirushi SW-EAE50

Sources

Specs checked October 2026. Prices and availability change, so check the current listing before buying.

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