Comparing Iodine Concentrations: A Side-by-Side Drop Chart

A visual, side-by-side comparison of how many drops of each Lugol's Solution concentration are needed to match a given amount of elemental iodine.

The Basic Rule

Iodine content per drop scales with the percentage on the label. Double the percentage and you double the iodine in each drop, as long as the drop size stays the same. That makes it easy to convert between strengths: a drop of a stronger solution equals several drops of a weaker one.

Equivalent Drops, Side by Side

Using a 2% solution as the baseline, here's roughly how many drops of each strength carry the same amount of iodine as one drop of a stronger one:

• 1 drop of 20% ≈ 2 drops of 10% ≈ 4 drops of 5% ≈ 10 drops of 2%
• 1 drop of 15% ≈ 3 drops of 5% ≈ 7½ drops of 2%
• 1 drop of 10% ≈ 2 drops of 5% ≈ 5 drops of 2%
• 1 drop of 7% ≈ 3½ drops of 2%
• 1 drop of 5% ≈ 2½ drops of 2%

Put another way, compared with 2%, a 5% solution delivers 2.5 times as much iodine per drop, 7% delivers 3.5 times, 10% delivers 5 times, 15% delivers 7.5 times and 20% delivers 10 times.

Why the Numbers Are Approximate

These ratios assume every drop is the same size. In practice, drop size depends on the dropper's tip, the liquid and how the dropper is held, so treat the chart as a close guide rather than an exact measurement. For mg-per-drop figures for our own bottles, see the drop-to-milligram conversion reference. To learn why drops vary, read Drop Size Variation Between Bottle Manufacturers.

When This Chart Is Useful

• Switching strengths: moving from 2% to 5%, or from 5% to 10%, without changing the amount of iodine.
• Fine-tuning: lower strengths allow smaller steps; a single drop of 2% is a much smaller change than a single drop of 20%.
• Comparing value: a higher strength uses fewer drops for the same amount, so the bottle lasts longer.

A Few Cautions

• Only compare products of the same type. A 5% Lugol's iodine and a 5% product of a different type may not carry the same iodine per drop. Check each product's Supplement Facts panel.
• Don't switch strengths and keep the same number of drops. Twenty drops of 2% and twenty drops of 20% are very different amounts.
• Follow the label, and talk with a healthcare provider before changing how much you take.

Our Strengths

Our Lugol's Solution is available in 2%, 5%, 7%, 10%, 15% and 20%, in 2oz and 4oz bottles. For help choosing, see 2% vs. 5% Lugol's Iodine and Reading Your Bottle's Percentage Label.

Frequently Asked Questions

Does a higher strength work differently from a lower one?
No. The solution is the same; only the concentration changes. A higher strength simply puts more iodine in each drop.

Should I talk to a doctor before starting?
Yes. Anyone considering a new supplement — especially one involving iodine — should check in with a healthcare provider first, particularly if pregnant, nursing, or managing a thyroid condition or thyroid medication.

Where can I find exact drop-to-milligram numbers for my bottle?
See our full drop-to-milligram conversion reference for exact mg-per-drop figures across every strength we carry.

Shop Lugol's Solution — the traditional, trusted way people have supported their iodine intake for over 200 years.

Ryan Whitfield covers the chemistry and wellness-routine side of iodine supplementation for the Iodine Journal.

This article is for general educational purposes only and has not been evaluated by the FDA. It is not intended to diagnose, treat, cure, or prevent any disease, and is not a substitute for advice from a qualified healthcare provider — especially if you are pregnant, nursing, taking thyroid medication, or managing a thyroid condition.