Updated on 10.04.11

Saving Pennies or Dollars? Reusing Ziploc Bags

Trent Hamm

saving pennies or dollarsSaving Pennies or Dollars is a new semi-regular series on The Simple Dollar, inspired by a great discussion on The Simple Dollar’s Facebook page concerning frugal tactics that might not really save that much money. I’m going to take some of the scenarios described by the readers there and try to break down the numbers to see if the savings is really worth the time invested.

Calista writes in: Does reusing plastic (Ziploc) bags save pennies or dollars?

Clearly, any time you reuse something, you’re going to be saving money. The question is how much money and whether that time invested is really worth the money you saved.

Right off the bat, I would probably argue that the biggest reason for reusing sandwich and freezer bags is the environmental impact they have. These bags really aren’t biodegradable and when you toss them in the trash, they go into a landfill somewhere and sit there for a very long time. Think hundreds of years. That’s not something I like to do if I can avoid it.

Another “right off the bat” point: I should point out that in an earlier post, I ran the numbers on rewashing and reusing Ziploc sandwich bags. I found that, for all of the effort of rewashing them using the dishwasher and reusing them, you only saved $1.42 per hour washing sandwich baggies. For me, this falls clearly into the “not worth it” camp from a purely financial standpoint.

Here’s the thing, though: we do wash some of the Ziplocs that come through our house. Which ones? The quart and gallon-sized freezer bags.

The numbers At my local warehouse club, I can get a box containing four sets of 38 gallon freezer Ziploc bags for $10.74. This results in a price of $0.07 per bag.

I can also get a box containing four sets of 54 quart freezer Ziploc bags for $9.53. This results in a price of $0.05 per bag.

I can rewash and reuse a freezer Ziploc bag about sixteen times until the seams around the edge begin to give. This includes relatively short stints in the freezer.

According to my calculations, the cost to run a full load is 15.6 cents worth of detergent and water. A typical dishwasher load also uses 1.5 kilowatts of energy, adding an additional 17 cents to a load, bringing the total cost to approximately 32 cents per load.

I can fit twelve quart Ziploc bags (turned inside out and spread as widely as possible across the tines) and eight gallon Ziploc bags into a single dishwasher load. This inversion and insertion takes me about fifteen seconds per bag, which means I could in theory do 240 bags per hour.

This means that the cost of cleaning a quart freezer Ziploc bag is about 2.7 cents, and the cost of cleaning a gallon freezer Ziploc bag is about 4 cents.

Running the numbers You could either buy 256 gallon Ziploc freezer bags at a total cost of $18.09, or you could buy sixteen bags at a cost of $1.13 and wash them fifteen times each (which would require an investment of an hour of time) at a cost of $9.60, giving you a total cost of $10.73. Your savings for an hour spent washing the gallon Ziploc freezer bags in a dishwasher is $7.36.

What about the quart ones? You could either buy 256 quart Ziploc freezer bags at a total cost of $12.80, or you could buy sixteen bags at a cost of $0.80 and wash them fifteen times each (which would require an investment of an hour of time) at a cost of $6.48, giving you a total cost of $7.28. Your savings for an hour spent washing the quart Ziploc freezer bags in a dishwasher is $5.52.

Now, that’s not a terrible savings, but it’s not a home run, either. For a lot of people, the reason for rewashing such Ziploc bags isn’t the financial savings, but the environmental benefit. However, it’s good to know that you do save some money by rewashing them, and the faster you are at running them through the dishwasher (and I’ll be the first to admit that my fifteen seconds per bag isn’t particularly dextrous), the better your savings rate is.

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  1. Tizzle says:

    I don’t have a dishwasher. I reuse some ziplocs, but not if they’ve held cheese (or meat, but I don’t eat that). Basically, if all I put in them last time was some lettuce, I’ll rinse the bag, and put more lettuce in. I rent, and don’t pay for my own water. For me, it’s a savings. Also, I’ve moved to using tupperware for as much as possible, and plastic grocery bags instead of ziplocs where possible (not in the freezer).

    I like this series, and I liked the original article, but this one especially has a ton of variables unique probably to each reader.

  2. Finance Nerd says:

    It also depends what you are using the bags for. For dry foods, like Cheerios, a quick rinse may be more than enough.

  3. Kat says:

    For us, the value of re-using ziplocks – as much as practical anyway – is in keeping at least that much plastic out of the landfills. I feel increasingly ‘guilty’ about anything that gets thrown away and try to find a secondary use for as much as possible.

  4. Jennifer H. says:

    I only bother about reusing if the bag hasn’t held anything particularly messy. Also, if I don’t feel like washing it at all, I just shake the crumbs out and make sure it’s dry, and then stash it in a pile that I have. That’s the place I go to if I have to dispose of something particularly messy but don’t want to use a new bag for it. Many ziploc bags get a second usage that way, and others get used more than that, if I’m using them to store homemade bread, in which case I don’t typically bother washing, just shaking crumbs out. Since I don’t have to bother with washing, it’s negligible time or effort on my part. That’s a good enough return on investment for me.

  5. Johanna says:

    Agree with the comments that reusing doesn’t necessarily mean washing.

    Also, don’t lose sight of the fact that you can’t save more money than you were spending on bags to begin with. You can calculate your hourly rate as $7/hour or $20/hour or whatever, but if you’re only spending, say, $5 a year on ziploc bags, there’s no way you’re going to save more than that.

  6. Norman says:

    I try to use ziplock bags as little as possible, but when I do use them, I don’t wash them to re-use, I just throw them away. I figure if I can keep from using them in the first place, I’m doing my part.

  7. josh says:

    They make 38 gallon bags?

  8. Other Jonathan says:

    Not only 38 gallon bags, but 256 gallon as well! And 256 quart! (though I’m not sure why they don’t just call those 64 gallon!)

  9. kc says:

    Careless writing + no editing = 38 gallon bags.

  10. jackie.n says:

    i don’t bother with washing freezer bags. when i separate bulk meat or chicken i wrap the item in plastic cling wrap, label and date with a sharpie, then place in a large freezer bag. when the bags empty i fold them in quarters and leave them in a designated section of the freezer. that way i know those are the “raw food” bags.

    when i bake a batch of cookies and then freeze them i reuse the freezer bags that i left in the tin foil/baggie/plastic wrap drawer. i know those freezer bags are the non “raw food” bags. i SIMPLY shake out any left over crumbs from the batch before and reuse. i don’t see any need to wash either bag between these types of uses.

  11. lurker carl says:

    I can’t imagine how anyone uses a dishwasher to wash baggies. My experience shows lightweight plastic bowls and lids easily fly about, I can’t see flimsy baggies staying put.

    This, along with many other unrealistic ideas over the years, makes me wonder if Trent REALLY does half of what he claims.

  12. valleycat1 says:

    Who ends up with 8-12 or even 20 bags at once that need to be washed? From Trent’s comment that he figures he can wash 240 baggies in an hour’s time, he must just be running them through a rinse cycle (20 bags/load = 240 bags/hour means 5 minutes/load including loading time). (I’m with lurker carl #11 & would like to see a photo of the dishwasher at the end of the wash operation.) Why not just rinse them out by hand?

  13. Gretchen says:

    You really are running low on ideas- washing baggies (which no one really does!) again?

  14. TLS says:


    I keep designated ‘raw’ bags in my freezer too. How funny to read that someone else does this. I figured I was just being lazy (it’s easier to just leave them in my freezer and reuse them, than to pull out a new one each time).

  15. Ash says:

    I wash my ziplock bags in the dishwasher and it works just fine. I turn them inside out. Thanks Trent for a fabulous article and keep up the good work.

  16. Larabara says:

    I have a dishwasher but don’t use it for plastic items. I found my plastic food storage containers tend to flip over and fill with water in the dishwasher. So I wash all the plastic, including the baggies, by hand. For me, a sink of hot, soapy water cleans plastic a lot better than my dishwasher and I can turn the greasy baggies inside out to give them an extra scrubbing.

    My problem is finding a good way to air-dry them…the glass holders on my dish drainer don’t do a very good job.

  17. jackie.n says:

    @#14 TLS. yet another example of great minds thinking alike.

  18. Rebecca says:

    I reuse heavier Ziploc brand bags as well as the thinner sandwich zip bags. I use the little thin store brand sandwich bags for veggies, sandwiches, grapes, and similar items for my work lunches. I only wash them with soapy water if something spills, otherwise, a good rinse will do.

    I don’t usually throw them out until they develop a hole or the zip part rips. Washing is easy – I toss them in the soapy dishwater when I’m washing other dishes, and dry them stuck upside down on big spoons or other longer utensils in the dish drainer.

    If I have a Ziploc freezer bag used for meat, I reuse it for meat but not for other lunch things.

    I feel it’s wasteful to use them once and throw them away.

  19. Lindsey says:

    @ #16 Larabara- I always handwash my baggies, and turn them inside out to dry. Otherwise, I find that I can’t keep them open enough & they get gross inside.

  20. Johanna says:

    @Grammar police: Actually, Trent is correct here, and it’s not even ambiguous. “38 gallon bags” means 38 bags that each hold a gallon. Bags that hold 38 gallons each would be “38-gallon bags.”

  21. Bill says:

    @#20 Johanna,

    Maybe my High school English teacher was justified in failing me.

  22. kc says:

    Johanna, “Four sets of 38 gallon bags” is confusing.

    “38 one gallon bags,” or if you like, “38 1-gallon bags” would be much clearer.

  23. Shelley says:

    Well, I remember when Amy Dacycyn floated this idea in her newsletter and I took to it right away. She didn’t re-use hers if they had stored meat. She also wrote about the economics of dishwashers and concluded that they were only the frugal option if you used the time saved to do other frugal things. Because I didn’t grow up with a dishwasher and my first experience was with an older one that didn’t do a great job, I’ve never got the habit of having an automatic dishwasher. But I do have the habit of using ziploc bags (I buy boxes in the US when visiting, as I’ve not found them here in the UK). Like Amy, I feel they save me space in the freezer. I’m sure it’s best not to re-use them if they’ve held meat or poultry and that’s what I would recommend others to do. However, I will admit that I re-use mine – whatever they’ve held – for as long as I’m happy with the outcome of my hot soapy water cleaning of them along with the rest of the dishes. I hang them to dry inside out on the inside of my pantry drawer and don’t put them away wet. I have ziplocks that are maybe 5-6 years old or even older. I don’t agree with Trent’s cost per hour savings altogether because I’m retired (at age 51) and I know that whatever else I do with my time, no one is going to pay me for the activity. My metric is simply not spending money on things I don’t have to so I’ll have more money to spend on things I want. I’m no frugal expert, nor an English major, I just thought I’d throw a positive comment in with the rest of this contrary lot.

  24. Annie says:

    I use the large freezer bags for my meats and fish and just wash it afterwards by hand. I can’t see using a dishwasher with ziploc bags, it takes 30 seconds to wash it by hand. I am trying to be eco friendly and am just starting out but why not wrap your sandwiches in tin foil and then put in the ziploc bags, that is how my parents used to pack my luches and i still do it now. I end up throwing away the foil and bring the plastic home to reuse tomorrow.

  25. Debbie M says:

    I don’t use these bags anymore. I use the re-usable sealable containers. They stack well in the cabinet and if you do it right, all the lids are the same size and can be in one stack. I get the square ones to be more efficient. The only negative is they don’t squish down to nothing when you’re done.

  26. Johanna says:

    @kc: You find it confusing? You seriously thought that there is such a thing as a 38-gallon ziploc bag, and that that’s what Trent was talking about? I kind of don’t believe that.

  27. Tom says:

    “Four sets of 38 gallon bags” is confusing.

    No it’s not. By contextually reading the article, when he prefaced his phrase by saying he washes quart size and gallon size bags, and buys them in bulk at the warehouse store, the syntax is not that confusing. I believe it would require hyphenation (38-gallon) to specify that those adjectives belong together. Perhaps it could have been more clearly written, gallon-sized bags would remove all doubt, but common sense prevails in this situation. I believe it is commonly understood by reading the entire article.

  28. Baley says:

    @KC “38 1-gallon bags” is wrong because one shouldn’t put 2 numbers together in a sentence without spelling one of them out, and “38 one gallon bags” would be incorrect, as well (should be one-gallon). So, maybe you should hand over your grammar police badge. :) As Johanna and Tom have pointed out, the phrase as Trent wrote it is not confusing.

  29. Jane says:

    I do the same as Jackie. I will often use the cheap sandwich bags to put home-made tomato sauce or marinated meat. Then I stick those in a larger freezer bag. Then I of course dispose of the cheap sandwich bag and reuse the freezer bags. Eventually those get icky too, and then they become bags for stinky diapers, cat littler, or whatever needs to be disposed. I find we only go through one small box of larger freezers bag at most annually. I also accrue them from other people who give me something in them. I reuse those too. So, all in all, my yearly budget for bags is probably $5. But we use glass pyrex for almost everything. I also tend to freeze my broth in pyrex, since it’s still hot when I put it in. Pyrex is the best!

  30. Jamie says:

    I turn all my Ziplocs inside out and go over them with a soapy sponge, then throw them into the dishwasher in the part of the silverware holder that has a lid that flips over the top to hold small items in place and run them through a cycle with the rest of the dishes. I then rinse them with clear water from the tap, spread the opening apart and place them upside down on the counter. Next day, turn them right-side out, place them upside down on the counter again. Next day, put them away. I do this until they don’t close anymore or get a leak and then use them one more time for scraps I’m saving for the dog. I don’t care what was in them. I clean them well enough that it doesn’t matter. I stocked up when Ziplocs were selling for $.50/box and coupons made them free about a year ago. I haven’t tried to run the numbers, but it feels good to know I’m not spending money on plastic bags all the time like I used to and keeping a little plastic out of the landfill.

  31. Cheryl says:

    RE: drying the bags. Put them over the top of a wine bottle. That holds them open. I usually dry with a towel first, then finish them up over the bottle to be sure they are completely dry.

  32. Tom says:

    because I’m a nerd, I found this example of ambiguous phrasing:

    Three hundred-year-old trees are in this forest.
    Three-hundred-year-old trees are in this forest.
    Three hundred year-old trees are in this forest.

  33. graytham says:

    You’d like the book “Eats, Shoots & Leaves: The Zero Tolerance Approach to Punctuation” – great read.

  34. Money Beagle says:

    We don’t re-use them to the point of washing them out, but if we have one that was used but is still ‘clean’ we stash them aside and will use them for non-food type things, such as keeping batteries, small parts for household repairs, and the like. It’s a small savings but I hate any waste of plastic since it’s going to be around long after we are.

  35. Finance Nerd says:

    @#32 —

    Let’s eat grandma.
    Let’s eat, grandma.

    Punctuation saves lives!

  36. kc says:


    My issue isn’t grammar, it’s clarity. I believe the statement is carelessly written.

    His description could have been clearer, and it would have taken only a moment to make it so.

  37. sandy says:

    Someone said nobody actually washes out bags. Well, I do and I have done so for over 20 years. My system is SUPER EASY. I turn the used bag inside out and send it down the laundry shoot. The bags are then washed in my washer with my kitchen towels that I bleach to disinfect. Since I would be running this load anyway and since I do it weekly so I never have a huge amount that requires me to do another load, my additional cost for washing them this way is $0. I then hang them upside down to dry (about 4/clip) and let time do the rest. Very fast and easy and it saves the environment, my conscience and some money.

  38. Jennifer says:

    I use ziploc bags in my daughter’s lunch almost daily, and she knows to bring the bags home. I shake out the crumbs and refill for the next day. Meat and any wet items go into a separate container. For example, this week she is having chicken soft tacos. I roll up a slightly warm tortilla shell and put it in a baggie. Put a 1/4 cup of grated cheese in another baggie. A small tupperware container holds diced chicken and another holds diced tomato. I wash those two containers out each night and refill. But the baggies need no washing, imo. Ditto for things like baby carrots, snap peas, etc. Those bags are perfectly clean enough to be refilled without washing.

    I cannot imagine throwing those bags out every day and using new! And her lunch box is too small to hold the number of tupperware containers necessary if I were to go that route.

  39. Johanna says:

    @kc: In what way is the statement unclear? If you found it unclear, that means you thought it might have meant something other than “38 one-gallon bags.” What did you think it might mean?

  40. MARY S says:

    Re;#32,33,35 good point! Eats,Shoots, and Leaves is one of my favorite books!

  41. Kerry D. says:

    I also reuse cereal bags (my teenage son eats nearly a box of Cheerios a day) as wax paper– shake out crumbs and store. Useful as either a wax bag, or open seams as a sheet of wax paper…super easy, kinder to the environment, and saves me a bit of money I used to spend on wax paper. Which helps buy more Cheerios (often generic, whatever is most economical)!!!

  42. Evita says:

    I was also confused by the 38 gallon bags……. but I am not an English speaker (and not an American, the word “gallon” does not have a clear meaning for me, but somehow it seems like huge bags).

    Anyway, I cannot imagine hoarding unclean Ziploc bags until I have enough to run a dishwasher load. Gross!

    I just toss the greasy ones and wash or rinse the others in the sink. Why make it more complicated than that ?
    But maybe Trent’s calculation is not supposed to reflect real life….

  43. slccom says:

    Evita, think approximately 3.5 liters and you’ll be close enough.

    If you shake the bag with your hand inside it, it breaks up water drops so that they dry really quickly, at least here in Colorado.

  44. lurker carl says:

    I just tried Trent’s method of washing some freezer baggies in the dishwasher on the top rack. It turned out much like I expected. After five minutes, two remained in place and the rest flash mobbed into a jellyfish orgy. No thank you.

  45. Golfing Girl says:

    LOL Lurker. I would like Trent to do a dishwashing machine vs. handwashing dishes–saving pennies or dollars? I simply don’t have enough dishes to wait until the washer is full so we end up hand washing everything and using the drying rack.

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