Percentage / Ratio Strength Converter

Less than they did. USP General Chapter <7> removed ratio expressions from the labels of single-entity injectable products in the US, so adrenaline that was sold as 1:1000 is now labelled 1 mg/mL. USP's labeling page links ratio strength to medication errors. Local anaesthetics combined with adrenaline, such as bupivacaine with epinephrine 1:200,000, are outside that rule and can still show a ratio. Older stock, other countries and textbooks still use ratios, which is where this converter helps.

Only for dilute aqueous solutions where 1 mL ≈ 1 g. For ointments, creams, and viscous liquids, w/v and w/w differ, so check the label. The US FDA describes w/v as the form for liquids such as oral liquids and w/w as the form for topical creams and ointments.

% w/v = grams of solute per 100 mL of solution (e.g. 0.9% sodium chloride = 0.9 g per 100 mL of solution). % v/v = mL of solute per 100 mL of solution (e.g. 70% alcohol = 70 mL pure alcohol per 100 mL solution). A solid dissolved in a liquid is given as w/v; a solid mixed into a cream or ointment is given as w/w.

Adrenaline (epinephrine) 1:1000 = 0.1% = 1 mg/mL · 1:10,000 = 0.01% = 0.1 mg/mL. Lidocaine 2% = 1:50 = 20 mg/mL. Bupivacaine 0.5% = 1:200 = 5 mg/mL. Hydrocortisone 1% cream is w/w, so it is 10 mg per gram, not per mL; this converter's mg/mL result applies to w/v liquids.