Calculator
Label Strength Comparison
Normalise printed concentration units, spot mismatched denominators, and compare like with like.
What you’ll need
- Two printed values, their explicit units, and the named substance and form
Enter the two label statements
Use the printed number and select its stated basis. A bare percent sign, ppm or an active-equivalent statement needs more context.
Enter a positive number and an explicit unit on each label. Leave an unstated denominator unspecified.
Using the tool
Compare the printed basis before comparing the values
Guide updated
What to check
Read the complete active line. A percent sign by itself does not distinguish mass per volume from mass per mass; a salt name may not state an active-equivalent basis.
Worked situation
Two fictional labels say 2% w/v and 20 mg/mL of the same stated form. Both give 20 mg/mL. A third label says 2% w/w, or 20 mg/g, which is a different denominator.
What to record next
Save the label text and the unit beside your comparison. Leave the ratio unanswered when the form or basis differs. This exercise cannot establish interchangeability.
What the comparison can show
The tool converts stated mass-per-volume units to mg/mL and stated mass-per-mass units to mg/g. It does not infer density, purity, equivalents, formulation identity or a dose. All entries stay in this page session.