Today I’m bringing you a useful dilution factor calculator to help with those quick calculations in the lab. To calculate the dilution factor, you need two things: the original volume of the solution you dilute and the final volume after diluting (or the volume you have added to dilute, in which case the final volume will be the original volume plus the volume you have added). Input those in the two first fields below, and you’ll get the dilution factor and the dilution performed in relative notation. Choose a specific notation from the dropdown box to change it to the standard one you use. See my other post if you need more help carrying out dilutions.
Maria Fuentes, PhD
I did my PhD in the Department of Chemical Engineering at Imperial College London. My research focused on mathematical modeling of the cell cycle in leukemia and involved experiments with cell lines. During that time, I had to count cells with a hemocytometer so often to track growth that I got tired and decided to build an app, HemocyTap, and share my knowledge on the topic here to help as many people as possible.
45 ml of fortune per 5 lit then dilution factor is 1.67.How ? can you explain
Hi there,
I’ve put your numbers in and I get 111.11 as a dilution factor:
This is assuming 45mL is your initial volume and 5L is your final volume. If 5L is the volume you add, then you would put 5.045L in the second box, and would get 112.11 as a dilution factor. Remember to change the units in the dropdown too.
Did I miss something? Let me know if you have other questions.
Cheers
Maria
Hi,
thanks Maria for u r reply.
i need to get dilution factor as 1.67.How ?
they mentioned as 45 ml of fortune chemical in 5 lit of water. then we will get 1.67 as dilution factor. i don’t know the concentration.
Can you please help me?
can you explain
Hi again,
I don’t really get it as 1.67 would be if you put 3L of the chemical into 2L of water. Are you sure those are the volumes, or are you sure 1.67 is the dilution factor you are seeking? Can you give me a link to the instructions you are following to prepare this solution? I might be able to help further then.
Thanks!
Maria
Hi I start with the dilution 0.15 and am supposed to end up with 0.25 dilution. This gives the dilution factor 5/3.
I don’t understand what that means, am I supposed to take 5 of the sample and 3 of the dilutent, e.g. water?
Hi there,
If 0.15 and 0.25 are dilutions, then practically what you need to do is concentrate more (not dilute). So for instance, if you have 10mL, the first dilution would require you to add 56.7mL and the second one would require you to add 30mL (it’s impossible for your to get to a more concentrated solution from a more dilute one just by adding water). There needs to be a centrifugation step in-between or something like that to allow you to concentrate more.
If it was the other way round, e.g. the initial one is 0.25 diluted and the final one is 0.15, then you would need to add the difference between the two volumes stated above (26.7mL of water) to the 0.25 solution.
Hope that makes sense, let me know if you have other questions.
Maria
Lets say I have dilution factors from 50 to 20. Does that mean that I take e.g. 1 ml of the sample and 49 ml of water for the first one, and then 20 ml from the first one and 30 ml water. Or do I do them separately by taking 1ml sample, 49 ml water (for 50 dilution factor) and then on a new tube with 2.5 ml sample and 47.5 ml water (df=20).
Thank you for the reply above.
What is the dilution factor of 1:1?
Hi Tun,
If you consider 1:1 as one part of sample to one part of diluent, then it’s two. If it’s one part of sample per total parts, then it’s one.
Hope that answers your question!
Hi Maria Fuentes,
Nice website. Happy to visit this site. I have problem calculating these numbers.
I have stock solution containing 3620 cell/microliter. (I have 10 ml of stock solution).
I want to fill 21 tubes each having 500000 Cell/70 microliter.
Can you simplify this and tell me the step wise calculation so that it can be used in future .
Thank you.
Hi Suchen,
Thanks!
Ok so to answer your question:
1. Calculate the final density:
final density = 500,000 cells / 70 uL = 7,142.8 cells/uL
2. From the stock solution, get the amount of cells needed. We will assume 22 samples here so you don’t run out of solution for your 21.
22 tubes x 500,000 cells = 11,000,000 cells needed
The total number of cells in the stock solution is 3620 cells/uL * 10,000 uL = 36,200,000 cells
Volume to take from stick solution = 10,000 uL * 11,000,000 cells / 36,200,000 cells = 3,038.7 uL
3. Now, the original solution is less dense than the final one (3620 cells/uL vs 7,142.8 cells/uL). You have to concentrate it, this is done by centrifuging the 3,038.7uL of stock solution and removing the supernatant. You can then resuspend in the right amount of fluid:
liquid to add = 22 x 70 uL = 1,540 uL
Hope that helped! let me know if you have other questions.
Cheers,
Maria
Good evening Maria,
Thanks for the calculator. I need your explanation for something still though. I’m doing an in vitro drug release test. And I’ve seen different mathematical equations all over the internet, I’m not even sure which is right. I’ll like you to confirm, using your calculator, is my final volume the volume of liquid I take out into the cuvet? Thanks
Regards
Bee
Hi Bee,
No prob, glad you find it useful.
The dilution factor is only calculated when there is volume of liquid added to the sample. For instance, say you start with 10mL of cell suspension. You add 5mL of water, so your final volume is 15mL. Then the dilution factor is final volume over initial volume, in this case: 15mL/10mL = 1.5. In your example, the final volume is the total volume you have after adding the liquid. If you already had sample in the cuvet, then the final volume is the volume you had plus the volume you added. If you are adding an already diluted solution to the cuvet, then the final volume is the volume of fluid you had in the tube you are taking it from (and you must have performed a diution in a previous step).
I hope that all makes sense! Let me know otherwise.
Cheers,
Maria
Question….
Starting with 2.25 mL distilled water
Adding .25 mL to the 2.25 mL
So total would be 3.25 mL
When I put it in the calculator my dilution factor is 13 or 1:13. Can you help explain how it came to is? I do not understand how to get that answer.
Hi K,
Thanks for checking out the calculator!
So: 2.25ml + 0.25mL = 2.5mL to start with (not 3.25mL)
I assume you are diluting 0.25mL with the 2.25mL of distilled water, so you put 0.25mL in the initial volume box and the final volume (2.5mL) in the final volume box. You get a dilution factor of 10 (2.5/0.25).
Does that make sense?
Cheers,
Maria
Hi Maria
I have cell suspension and if I add 5 ML of media in it for re-suspension. What will be the ratio? Will it be 1:5 or 1:6?
Thanks
Hi Irfan,
It depends on the volume of cell suspension you had. If it was 1mL, and you add 5mL, then the ratio will be 1:5 (sample:diluent) or 1:6 (sample:total).
Hope that helped!
Cheers,
Maria
Hi Maria,
I have 250 ml of total volume containing diatoms cells. Now i want to count these diatoms cells through Hemocytometer but i don’t know about the Dilution factor, so how to calculate these cells?
You only need to specify a dilution factor if you diluted your sample before measuring it. So, if you took 1 uL of sample and added 99 uL of water, mixed that together and then put that into the hemocytometer, you would have diluted it by a factor of 100. Which would be a ratio of either 1:100 (sample to total volume) or 1:99 (sample to diluent volume).
If the sample you are measuring was diluted from some other source and you do not know by how much, then you would not be able to find out. You would have a concentration of cells in the sample, and you know it is at least that much in the original, at a minimum.
Hi Maria,
If we have a Stock solution of control Antibody 1.8mg/ml and we want 1.2microgram on the gel. So I calculated the dilution factor which came out 0.66microlitre. But my professor told me that we would take 1:1 dilution and I did not get it why we will take 1:1? Could you please help me to explain?
I would be very thankful to you!!
Hi Pragya,
The dilution factor is the inverse. That is, it is the number of times you multiply the new concentration to get to the original concentration; equivalently, it’s the number of times more volume of solvent you add to a given volume of your stock.
So the dilution factor between 1.2 microgram/mL and 1.8 mg/mL is 1500. Expressed another way, it is a 1:1500 dilution (which = 0.000666…., as you saw! Though it doesn’t have units).
I’m not certain what you are saying about your professor. Sometimes low dilutions are expressed as the amounts to add, rather than the final volume. It is possible that your professor was saying they wanted you to add 1 part of X to 1 part of solvent (same as 1:2 dilution), but I’m not certain why that would be so, based on your example.
Could you please explain more?
Best,
-Nick
Hello Nick, how can I calculate dilution factor of proein (0.2mg/aliquot) made up to 1.5ml with distilled water
You need to know the volume of your aliquot. The factor would be the final volume divided by the original volume.
Hi,
If 500ul of a sample is added into 500ul of diluents, (1:2 dilution), repeated 2 times, what is the final dilution factor?
Is it 4? (from the first dilution, the dilution factor is 2, and multiply again by 2 for the second dilution). Is this correct ?
Yes! Each time you dilute, you multiply the factors for each step. This is known as a serial dilution.
How would I find the dilution factor from the following? Im struggling Please would love any help.
To calculate the concentration of salicylic acid within the aspirin product, as aforementioned above, a small sample (0.04 g) of the synthesised crystals is dissolved in water/ethanol, to an initial volume of 25 mL. From this starting solution, 5 mL are taken and reacted with iron (III) nitrate to form a total volume of 100 mL.
5 mL into a total of 100 mL is a dilution factor of 20 (total / initial)
Hi,
I am adding 0.5ml of sugar sample to 0.5ml distilled water. Then I adding in 1.0ml dns reagent and after cooling 1.0 Rochelle’s salt. What is the dilution factor here? I am confused if my final volume is 1.0ml (sample + water) or 3.0ml (sample + water + dns reagent + rochelle salt).
It sounds like this is for a specific assay, and the answer may depend on the assay. It is true that the dilution of your sugar in the final mix would be out of 3.0 mL. But it’s also possible that this assay refers to the dilution prior to adding the reagents.
your an actual legend for having the ingenuity to construct this platform
Hi!
I am struggling to calculate this problem. Please send help.
If the dilution factor in test tube 1 is 1:10 with 1.5 ml solution, what will be the dilution factor of tube six if you transfer 0.5 ml to the next tubes?
It would depend on the volume of the next tube. 10 * (x / 0.5)
Hi,
I have a question and would appreciate your insight. If I have a solution that’s 3ml, and I take 1 ml of that initial solution and dilute 1:2, by adding 1 ml of something else. Is my dilution factor 2 or 2/3? Thanks
Hi Hannah, sorry for the delay!
Your dilution will be 2.
Occasionally, you may care more about the total amount of substance in the original solution, and the fraction of that that you retain. But in that case, you wouldn’t care about the final volume; you’d just say it was 1/3rd of the original.
But for dilutions, what matters is the components added together.
Hey –
I have a question – say i have 20ul of stock and dilute it to 200ul – a 1:10 dilution or a dilution factor of 10. But then i take 20ul of that 1:10 and add 20ul of trypan blue…. what is my dilution factor then ? 11 ? or 20?
Hi Jade!
Dilutions are multiplicative.
Your first dilution was a factor of 10x, and your second dilution was a factor of 2x, so your total dilution is 20x.
Hey, what dilution factor should I take if my sample is undiluted?
Hi Zeeshan, in that case you should use a dilution factor of 1