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About this tool
Turn a prescribed dose into millilitres, the right oral syringe size and the exact marking to fill to.
The Liquid Medicine Measuring Guide converts a prescribed dose into the millilitres you actually draw up, using the proportion volume = dose in mg divided by concentration in mg per mL. It picks the smallest oral syringe that holds the dose in one draw, rounds to that syringe's printed graduation, and shows how many milligrams the rounded marking really delivers. It exists because household teaspoons have been measured anywhere from 2.5 mL to over 7 mL, which is why medicines-safety bodies insist on millilitres and a syringe.
Open Liquid Medicine Measuring Guide on AltFTool — it loads instantly in your browser.
Add your input to the workspace.
Adjust the options until the result looks right.
Copy or download the output and put it to work.
Chooses the smallest device that holds the dose, because a small volume in a large barrel has far more relative error.
Reports the dose the nearest graduation actually delivers and the percentage difference from what was prescribed.
Converts bottle size into doses and days of supply so you know when to reorder.
A medicine teaspoon is exactly 5 mL and a tablespoon is 15 mL. Kitchen teaspoons are not: studies of real household spoons have found volumes from about 2.5 mL to over 7 mL, so a spoonful can deliver half or one and a half times the intended dose.
Divide the dose in milligrams by the concentration in milligrams per millilitre. A bottle labelled 125 mg per 5 mL is 25 mg per mL, so a 200 mg dose is 200 divided by 25, which is 8 mL.
The smallest one that holds the whole dose in a single draw. Measuring 0.6 mL in a 10 mL syringe is far less accurate than in a 1 mL syringe, and safety guidance advises against using a syringe when the dose fills less than roughly 40% of the barrel and a smaller size is available.
You can only measure to the nearest printed graduation, so the tool shows the dose that marking actually delivers and how far off the prescription it is. If the difference is more than a few percent, or the medicine has a narrow safe range, ask the pharmacist whether to round up or down rather than guessing.