# Help Needed: conversion of medicine by weight to volume **URL:** \ **Category:** Factual Questions\ **Created:** [November 29, 2005, 1:04am UTC](https://boards.straightdope.com/t/help-needed-conversion-of-medicine-by-weight-to-volume/333145 "2005-11-29T01:04:35Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [November 29, 2005, 1:04am UTC](https://boards.straightdope.com/t/help-needed-conversion-of-medicine-by-weight-to-volume/333145/1 "2005-11-29T01:04:35Z")
I have a powdered supplement for my sick cat that says we’re supposed to give him 4,000 milligrams of the powder. We don’t have a scale that’s reliable for gram weights, so is there any way to convert this to an equivalent of teaspoon or mililiters? ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [November 29, 2005, 1:11am UTC](https://boards.straightdope.com/t/help-needed-conversion-of-medicine-by-weight-to-volume/333145/2 "2005-11-29T01:11:46Z")
Not unless you know the density of the powder–and that’s going to vary considerably depending on how tightly it’s packed, and even the relative humidity. I would take it to a local pharmacy and ask the pharmacist if he would be kind enough to weigh out one or more individual doses for you. They would have accurate scales specifically for weighing out dry medications. ---
**Author:** ![spingears](https://avatars.discourse-cdn.com/v4/letter/s/ebca7d/32.png) [@spingears](https://boards.straightdope.com/u/spingears)\ **Post date:** [November 29, 2005, 1:36am UTC](https://boards.straightdope.com/t/help-needed-conversion-of-medicine-by-weight-to-volume/333145/3 "2005-11-29T01:36:06Z")
> [@Lumpy](#): > > I have a powdered supplement for my sick cat that says we’re supposed to give him 4,000 milligrams of the powder. We don’t have a scale that’s reliable for gram weights, so is there any way to convert this to an equivalent of teaspoon or mililiters? Do you know how much of the powder (gross wt) on hand? Divide by 4 or 4,000 to find how may doses! Otherwise get your friendly apothecary to weigh out the correct amount and then give the cat approx. the same amount. Teaspoon or tablespoon measures might be of help at that point. ---
**Author:** ![Immortal\_Sin](https://avatars.discourse-cdn.com/v4/letter/i/7c8e57/32.png) [@Immortal\_Sin](https://boards.straightdope.com/u/Immortal_Sin)\ **Post date:** [November 29, 2005, 1:56am UTC](https://boards.straightdope.com/t/help-needed-conversion-of-medicine-by-weight-to-volume/333145/4 "2005-11-29T01:56:02Z")
4000 mg converts to 4grams…with that in mind, you can go to your local wal-mart and purchase a very inexpensive food scale…also with that if your new inexpensive food scale does not offer grams I am sure that you can find a convertion table on line…to convert grams to ounces…4 grams is only a few onces anyway… ---
**Author:** ![Q.E.D](https://avatars.discourse-cdn.com/v4/letter/q/51bf81/32.png) [@Q.E.D](https://boards.straightdope.com/u/Q.E.D)\ **Post date:** [November 29, 2005, 2:00am UTC](https://boards.straightdope.com/t/help-needed-conversion-of-medicine-by-weight-to-volume/333145/5 "2005-11-29T02:00:09Z")
> [@Immortal Sin](#): > > 4 grams is only a few onces anyway… 4 grams is not even ONE ounce. There are 28.35 grams per ounce, so 4 grams is a little over an eighth of an ounce. Not too many inexpensive food scales will weigh such a small quantity accurately. ---
**Author:** ![outlierrn](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/outlierrn/32/3005_2.png) [@outlierrn](https://boards.straightdope.com/u/outlierrn)\ **Post date:** [November 29, 2005, 3:01am UTC](https://boards.straightdope.com/t/help-needed-conversion-of-medicine-by-weight-to-volume/333145/6 "2005-11-29T03:01:41Z")
when we reconstitute in the er, the med is usually labeled with the vol to use, as in 10 ml water with 1 packet yields 5mg per ml. Usually, the weight refers to the active ingredient, as in 10mg of morphine sulfate refers to 10 mg of morphine, + whatever mg of sulfate. Your medicine should have some kind of reconstitution instructions, maybe on a larger package. Without that it’s a real crapshoot,