This is a continuation of a long topic, addressed by post number rather than by page. Start at post 1.
Tools that run entirely in the browser send nothing anywhere, which matters more to some people here than others and is worth stating either way.
If anyone can point at the primary source I would be grateful.
Noted, and thank you for writing it out rather than summarising it.
The reconstitution calculation is total mass divided by total volume for concentration, then dose divided by concentration for volume, then volume times one hundred for units on a U-100 barrel. Three steps, and every error is in one of them.
None of the above is medical advice and I am not qualified to give any.
Precision and significant figures: the calculators do not round to match your input precision. If you input values to one decimal place, the output might have more. Use significant figures appropriate to your input precision.
If the premise is wrong, everything after it is decoration.
Coming back to post #64, because the follow-up matters more than the original answer.
Why calculators are not medical advice: they do arithmetic. Medical decisions are not arithmetic. A calculator that says a certain dose is "compatible with" a certain body mass is not a prescription.
Post #67 is right about the mechanism and I think understates the practical bit.
Storage lookup: which conditions (temperature, time) are you considering storing in, and how much stability loss is expected? The calculator gives a rough estimate based on typical stability data. Not a substitute for your compound's specific stability data.
Post #67 put the caveat in the right place and I want to underline it.
A saved calculation is worth more than a remembered one. Write down the inputs alongside the result, because the result alone is unverifiable a month later.
Where a calculator and your own arithmetic disagree, the productive move is to find which step differs rather than to decide which is right.
Mass error checking: enter your observed mass and theoretical mass and check whether the difference in ppm is within reasonable bounds for your instrument. Useful sanity check on LC-MS results.
The evidence for this is thinner than the way I have phrased it suggests.
Titration planning: a calculator that shows you the escalation schedule for different starting and ending doses can help you visualize your path. Actual path might be slower or adjusted for tolerability.
It is the sort of thing that seems obvious in retrospect and was not at the time.
Where I part company with post #72, and it is a narrow parting.
The most common input error is entering the vial mass in the concentration field. It produces a plausible number, which is why it survives.
On reflection I would soften that slightly.
Picking up post #74: that is the part I would want checked first.
Unit-conversion tools are only as good as the assumption they make about the syringe. Ask what barrel and what graduation interval it assumed before trusting the units figure.
This is the first time the answer has come with its own limits attached. Appreciated.
Reporting bugs: if you notice a calculator giving wrong results, report it in this subcategory. Bugs are fixed when identified.
I had written a reply contradicting post #77 and deleted it. Here is what survived.
Do the arithmetic by hand the first few times, whatever tool you use afterwards. A calculator with a wrong input gives a confident wrong answer and there is nothing in the interface to tell you.
A calculator that shows its working is worth ten that give an answer. The whole value is being able to see which step you disagree with.
Worth separating two things that post #77 runs together.
Tools that run entirely in the browser send nothing anywhere, which matters more to some people here than others and is worth stating either way.
Unit-conversion tools are only as good as the assumption they make about the syringe. Ask what barrel and what graduation interval it assumed before trusting the units figure.
Precision and significant figures: the calculators do not round to match your input precision. If you input values to one decimal place, the output might have more. Use significant figures appropriate to your input precision.
Post #81 put the caveat in the right place and I want to underline it.
Nothing a calculator produces is medical advice, and a correct calculation on inappropriate inputs is still an inappropriate answer.
Old habit: I write down the expected answer before I calculate it.
Building on post #81 rather than restating it.
A saved calculation is worth more than a remembered one. Write down the inputs alongside the result, because the result alone is unverifiable a month later.
Not the answer, but possibly the question that gets there.
Significant figures in the output should not exceed what the inputs support. A concentration calculated from a nominal vial mass is not known to four decimal places.
Written from notes rather than memory, which is why the numbers are specific.
Rounding behaviour is where two tools disagree. One rounding to the nearest graduation and one to two decimal places will produce different advice from identical inputs.
That matches what I have seen, for whatever a single anecdote is worth.
Post #86 is the version of this I will quote in future. One addition.
Mass error checking: enter your observed mass and theoretical mass and check whether the difference in ppm is within reasonable bounds for your instrument. Useful sanity check on LC-MS results.
The general answer and the answer for your case may diverge here.
I read post #86 twice before replying, because I had assumed the opposite.
The reconstitution calculation is total mass divided by total volume for concentration, then dose divided by concentration for volume, then volume times one hundred for units on a U-100 barrel. Three steps, and every error is in one of them.
It is a small point and it changes the answer, which is an awkward combination.
Adding thanks rather than a view. I do not have a view worth the space.