Did you use this?
Jesus. Way to make me feel like an illiterate walking into a library during a Great Poets convention. I'm sorry. I thought it was pretty clear that I don't have any idea what I'm doing.
I dont think anyone in the community is trying to speak down to you at all. it would give the community a better idea of what the possibilities are if you listed the ingredients. I think the best you might do is like a 70/30 PG/VG mix @ 12mg given the ingredients that you have. best thing to do is to make a 5ml bottle and test it. you may find that 5% coffee is to much and you can reduce that to maybe 3% you can now add 2% more VG on the next test run, same goes with the pumpkin spice 10-15% might be high so you could also reduce those and add VG instead.
This from WakeNVape's Calculator. Its a pretty nice and easy calc to use.
Nicotine Base 2.5 ml 50 Drops 50% coffee 0.25 ml 5 Drops 5% pumpkin 0.75 ml 15 Drops 15% VG 1.5 ml 30 Drops 30% 5ml - 12mg - 70pg / 30vg
There are many eliquid calculators available.
They can be subtly different so I suggest you try a few until you find one that makes you happy.
Here's mine...
http://www.wakenvape.com/eliquid_calculator/index.php
I like this calculator. I pre-mix my "working" 24 mg nic base for experimenting 70/30 and then cut it with 0 nic 70/30 from another pre-mix bottle. I use out of them for a while instead of always getting into the big nic bottles. But sometimes I want a different PG/VG ratio in my test and this one will be helpful for that. Upvote for making me happy. Nice work.
Here's the easiest thing:
Buy nicotine at twice the strength you vape.
Mix ratios: 5 parts nicotine solution, 4 parts PG/VG, 1 part flavor.
So, for 10ml it'd be 5ml nic base, 4ml pg/vg, 1ml flavor
or for 30ml, 15ml nic base, 12ml pg/vg, 3ml flavor.
To balance the PG/VG 50/50, use VG nic base and PG to cut it. Flavor is usually PG, so you should add that to the PG side.
As others have stated, getting to 24mg/ml of nic is impossible with what you ordered. Everything you add into the nic will dilute the concentration, thus starting with 24mg, and wanting to go 50/50, you're looking at a max of 12mg/ml, maybe.
I can't see what nic solution you have, is it PG, VG, or the 50/50. If it's already 50/50, you can get close by just adding the flavors (You'll likely end up somewhere around 20-21mg/ml if you do that). If it's pure PG or pure VG nic, you can add flavorings, but you're not going to be able to get close to 50/50 and still be less then 24mg/ml.
Rule of thumb, use nicotine that's twice the strength you want the final product, or higher.
However, now might be the time to drop to 12 or 18mg. With the espresso and whatever is to the left (too blurry for me to read) it might end up still giving the throat hit. Heavier flavors can often give you the same satisfaction at a lower nic. You can also increase the PG (something like 70/30 Pg/Vg) in order to increase throat hit. You might find that with a good enough throat hit, the need for the higher nic isn't there anymore.
I'm aiming for a 50/50 24mg mix. This will be my first blend.
I don't think that's possible with what's there. Is the nic in PG only? If so, you can't do 50/50 at 24mg. You'd use your base at 100% meaning, 30ml of nic base for a 30ml bottle; 100% PG. If you add any VG it'll dilute the nic level. Even if the nic base is 50/50 the addition of the flavor will decrease the ratio (but not by a lot). You need either a higher nic base or shoot for something lower. You could do 22mg and get 50/50 if your base is 50/50 with 5% flavor.
As for the flavors, coffee's are usually strong. I'd start at 5% and cure it a week at least. The pumpkin spice I'd do at 10-15%. But the addition of the flavors will throw off the ratio.
Edit: This is likely why your calculator crashed. The desired levels aren't possible given the ingredients.
Is that a 24 mg nic solution I see there? This will be easy. Put you PG and VG in the cabinet, 1.5ml coffees and 3ml pumpkin spice. 24ml nic. Cant do 50/50 because the nic will dilute
I'm using a mobile e juice calculator... I entered what i thought would be the correct amounts...5% of cappuccino/espresso each, 10% PS for a 30 ml of 50/50. The app force stopped out of confusion.
Reason being, is you can't get to 50/50 at those mixtures.
Starting at 24mg/ml and adding anything will drop you below 24mg/ml.
Do the same thing, but make the target 12 or 18mg and the app might not freak out on you.
The calculators are good, but I have found most freak out pretty bad if you don't do some of the basic math yourself. I was helping someone test an online one, and purposely did things like you did and got it to start giving me negative numbers for some components. It's great when it tells you to add -5ml of PG.
Your first job is to dilute the nicotine. What's the concentration there? How much diluent (pure VG/PG) do you have? Whatever that second number is, multiply that by your target concentration, divide by the concntration of nic you want, and that's how much nic juice you use. Past that, season to taste.