Ammonia Calculator for Aquariums

I included this calculator in my article on performing a fishless cycle but wanted to make it a separate post for easier access.

This is a simple calculator.  Make sure to select your units (gallons or liters) as a first step (based on your preference).  The concentration depends on the ammonia you use and is usually between 5% and 10%.

The output is in mL and drops (useful for small quantities of nano aquariums).

Source for Ammonia:

For aquariums, make sure to use Ammonia free of impurities (soaps, dyes, surfactants).  I only know of two that are confirmed suitable: Ace Hardware (EDIT: I don’t see that this is sold online any longer – it may be available in a store.) and Austin’s Clear Ammonia (available on Amazon).  Ace ammonia is 10% concentration; Ammonia Clear is around 5% concentration.

There is now an aquarium-specific product – Dr Tim’s Ammonia. I still prefer the options listed above as they are cheaper, and some people have indicated the percentage of ammonia contained in the Dr. Tim’s product is unclear.

58 thoughts on “Ammonia Calculator for Aquariums

  1. Nate – perhaps they have changed their formula, but the Ammonia Clear you link to on Amazon appears to be 1%. I purchased it and used your calculator at 5% concentrate for 5ppm and couldn’t get close.

    According to comments on the product, it is 1%. When I used your calculator at that concentration it was at 5ppm in no time.

    Thanks for this blog. You’ve made me look like a nano tank expert!

      1. The MSDS for Austin’s lists the percentage of ammonia at 05-2.5%. The bottle currently doesn’t say what it is.

    1. I agree. This is a terrific calculator and tool for us. THANK YOU. And yes, you’re correct. Austin’s Ammonia Clear seems to be 1%. When adjusted for that, it matches this calculator almost perfectly.

  2. Has the link to the calculator broken? It’s not appearing anymore?

    1. Thank you so much for pointing that out. I fixed a problem with the plugin and hopefully it is back up.

      1. Yes it’s back thanks Nate! Its so useful, your whole site is for that matter! It’s helped me so much

  3. Hello, I stumbled on this calculator and it is going to come in real handy.

    I have reviewed many ammonia cycle prprocesses and am confused to which is the best, most stable and correct method to use.

    Could you be as kind to email me easy to follow detailed step by step instructions on how to complete the process you use?

  4. What about ammonium chloride products, such as DrTim’s. No options to accommodate these type of fishless cycling ammonia additives.

    1. That is an aquarium specific product. If you choose to use something like that, just use the directions that come with the product.

  5. I can’t seem to find out the concentration of Ammonia in Austin’s Clear. Their website says 1% to 2.5%, but this can’t be right since my ammonia levels were off the chart when calculating 2.5%. Does anyone know the Austin’s Clear true Ammonia percentage?

    1. I contacted the company, because the % is not listed anywhere on the bottle. They told me it was 2%.

      1. 2% is also what I was told when I called recently. Dosing based on that and the calculator confirmed that it was 2%.

  6. Hi, Nate. Great guide. Thanks for writing it. However the calculator site is no longer working. Are you able to fix it? Thanks in advance!

  7. I’m in the middle of cycling an aquarium at the moment and am using your calculator to dose ammonia with transfer pipettes. Every time I add ammonia I test an hour or two later to confirm the level. It’s bang-on every time. Thanks for the great calculator!

    1. Thanks for the feedback! So glad you have tested it and it’s accurate.

  8. The ammonia clear material safety data sheet indicates ammonia between 0.5 to 2.5%:
    “1336-21-6 0,50-2,50 % Hidróxido de amonio”
    Information from their web site.

  9. Great calculator. I have read many pages on how to cycle but few give enough information on how much ammonia to add, just a few drops and check levels. This took me quite a long time to get to a level I needed. I will be sure to use this when I dose again as it will be quicker. My fear is that I may have overdosed now as it took me more than suggested to get to my test to read at 4 ppm, time to verify with a new kit.

    1. Update, after several days my ammonia came down to zero with no water change. Yeah!!! I used the calculator and dosed appropriately back to 4 PPM and had the level return to 0 in 24 hours. I did use filter media from my old tank and some ornaments to seed the new tank. I guess sit back and wait was good advice. I was very worried the overdosing by 4-6 times was going to kill all the bacteria, but they bounced back and took care of the ammonia. Nitrites followed suit, I’m cycled in. Thanks for providing the calculator.

      1. That is great! It’s interesting how it just turns a corner and all the sudden – it’s cycled.

  10. I use ammonia from market basket- bottle doesn’t say what % concentration it is. Anyone know?

  11. Nate, the calculator is indispensable! I refer new aquarium users (fishless cycling) almost every day! Thank you!

  12. Dr. Tim’s Ammonium Chloride 4 drops per gallon bottles works perfectly @ 4.6% Ammonia % with this calculator.

  13. I believe if anybody is wondering, and please correct me if I’m wrong but Dr. Tim’s ammonia is about 4%.

  14. It’d be nice to be able to enter a value in the ‘Resulting Ammonia Solution to Dose’ field.

    1. Just curious – if you entered a value into ‘Resulting Ammonia Solution to Dose’ field, what would you be solving for?

      1. That way, you can take a predetermined amount of ammonia and know what it will raise the ppm to. I have a dropper that I know can hold 5ml of liquid but it’s not marked.

  15. I tested this calculator using the Ace Ammonia and it took me about 3X the indicated amount to achieve the desired concentration.

    I suspect your math is correct. I wonder if the bottle I got from Ace was not 10%. It says 10% on the label but who knows how tight their quality control is. I wonder also if the Ace ammonia degrades over time.

    I used a 1 ml dosing syringe to draw the ammonia out of the bottle and put it in a one gallon jug of water. Then tested the water with the API master test kit.

  16. Hello.

    Had tropical for a few years now and about to start my first marine tank.
    I always use ammonia when cycling but finding it hard to see how much ammonia to use. Most marine enthusiasts seem to favour the “throw some live rock and then some hardy fish, it’ll be fine” method.
    Will the amounts given in your calculator work for saltwater?

    Thanks in advance

    1. Yes, this calculator and the instructions work the same for a marine tank.

  17. What is the formula you are using? Do you have a reference to it? I have tried other calculations and come up with higher amounts to add. Also when I check the ammonia to see 5ppm the API kit shows something like a deep blue green using your formula. When it is at 0.25ppm it shows light lime green.


    1. Check what inputs you are using in the calculator. As far as results, check the percentage of ammonia you are using, and check your test kit accuracy and your test methodology.

  18. Hey! Here in Greece I only have access to powder ammonia… The label says it’s 100% ammonia. Any idea how I can calculate how much I will need?

  19. I’m confused, the solution dose result I got was not similar to the test I did with ammonia test kit (API). I’m using the same ammonia source I’ve used 1.5 years ago to cycle my tank, and back then the result is always similar. Now whatever I aim for the result is always lower on the test kit like one third. Any thought?

    1. I really don’t know, other than to tell you API ammonia test isn’t that great and it doesn’t get better as the shelf life extends.

  20. @Nate, could you recommend a test kit?

    Also are the dosing amounts daily?

    Many thanks for this.

    1. I’ve had much better luck with the Salifert Ammonia Test Kit. Accurate and much easier to read than the API ammonia test.

      I don’t know what you are asking by “are the dosing amounts daily?” If you dose (once) using the calculator, it should raise ammonia to the target ppm.

      1. Thank you Nate.

        I guess what I meant to ask was if the Ammonia drops below 5ppm, does the ammonia need to continue to be topped up to 5ppm until I see 0 nitrite and nitrate steadily rising?

  21. Has anyone come up with an accurate percentage for DR TIMS AMMONIA? I contacted Dr Tim himself and even he didnt seen to know what I was asking for. Showed him this website too.

    1. Amazon reviews for Dr. Tim’s Ammonia complain that it is not accurate/consistent. Good luck.

  22. Hi Nate.
    I’ve been cycling with ammonia for a month. First time with ammonia. Following the ammonia calculator. Adding 4.5 mls for a 36gl. It’s gone every morning. Nitrites have been stuck at 2 for weeks. Ammonia is gone within hours? I did 50% wc then Added 4.5mls one hour after. Should be 2. It shows .5 Any idea why?

    1. Regarding the ammonia result, make sure your test kit is not expired and that you are using the proper method. If it’s an API test kit, those are prone to errors and/or difficulty reading. Also know that the calculator has you enter the percentage of ammonia concentration. There is some variation at times between what the label says and reality.

      Are you testing Nitrate? It’s difficult to know for sure what is going on without all your readings (ammonia, nitrate, nitrate) through the process and some other info (like if you started with some ‘seeding’ material from an established tank).

  23. For ammonia, I just purchased the cheapest of cheap ammonia at the grocery store. It’s so cheap (about $1.50 for 1/2 gallon of it) that it will be buried on the bottom shelf. It had the ingredients listed as: Ammonium Hydroxide. No concentration listed. That’s it, just pure ammonia like our grandmothers used to clean with. Always check the ingredients label but in general the cheaper the ammonia the more likely it is to be just plain ammonia and the lower it will be on the supermarket shelf. As far as concentration – that may be difficult to find. If you can’t find it on the bottle then assume it is 5% then aim for a concentration of either 2 or 3 ppm – measure the ammonia in the tank and if it reads too low then add another addition of the ammonia – same amount. Next time assume it is 10%. and only do 1 addition of 10% ammonia. Not a perfect solution but worst case if you go way over the PPM’s then do a partial water change to lower the ammonia. With this type of water change the replacement water would need to be SALT water (not pure water like you do when water just evaporates – because salt doesn’t evaporate) . In this case you’re removing saltwater so you need to return it with salt water. Now I last cycled a tank using the formula of 2 drops per gallon, I had a 90 gallon tank so that was 180 drops of ammonia. It came out to a little higher than 2 ppm almost color charted to 3 ppm – so maybe 2.5? Next time I’ll use this calculator. Still with adding bacteria it only took 4 weeks to cycle my tank rather than the usual 6 weeks. I also let my ammonia drop to zero twice, then added it back – the second time it got to zero almost immediately so I just waited on the nitrites to drop to zero and considered it cycled. I have 4 very large fish in there now – tough as nails but I bought the 90 gallon tank just for them because the 50 gallon was nowhere near large enough (they are are DoJo’s and are only supposed to get to 8 inches in captivity (2 feet in the wild). Mine must think they are in the wild because they are about 12-15″ long. Look like eels with wiskers – very friendly and fun loving and get very bonded as a group. I love these guys.

  24. My Ammonia Clear has a surfactant yet nobody else mentions it. Also it’s ammonia hydro. It’s Publix brand. Can I still use it?

    1. I’m not familiar with the brand of ammonia you are mentioning, but it doesn’t sound like a good option. If you are not sure, I’d move on and try to find a more reputable ammonia source.

  25. Has anyone recently used the Austin’s Clear Ammonia? I just dosed my tank tonight at the 1% and it sent my ammonia levels off the chart. I am thinking I may have gotten a batch that is on the stronger side. Their safety data sheet provides a range of .5 – 2.5%. Frustrating not knowing what exactly is in the bottle. I should have aired on the side of caution and used the 2.5 instead. Its certainly easier to add drops of ammonia than doing a water change lol.

    1. Good suggestion. Also, maybe dosing a container of water separately as a test before you do it to your tank (to verify the concentration of your ammonia). Also, a good test kit that is not expired (an issue I have ran into).

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