The real monthly cost of a supplement: how to work it out

The real monthly cost of a supplement is the total you pay for everything on the order, divided by the number of days the product actually lasts, multiplied by 30. The price on the front of the sales page is only a starting point, because bundle size, shipping, tax, add-ons and how you take the product all move the number.

This guide gives you a formula, a worked example with clearly labeled illustrative numbers, and a checklist you can run in five minutes before you buy.

What is the formula for cost per month?

Use two steps:

1. Total paid = product price + shipping + tax + any add-ons you accept.
2. Cost per day = total paid divided by days the product lasts. Cost per month = cost per day times 30.

The tricky part is "days the product lasts". That depends on servings per bottle and how many servings you take a day, not on the "30-day supply" wording in the ad. Days per bottle = servings per bottle divided by servings per day.

How do you find servings per bottle and days per bottle?

Look for the Supplement Facts panel. The FDA's dietary supplement labeling guide covers the Supplement Facts panel and serving sizes, and the panel is where the label states the serving size and how many servings the container holds. If the sales page never shows a panel, that is worth noting, since you cannot check the math without it. Several of our reviews flag exactly that.

Then compare the label serving with what the sales page suggests. A few examples from our own reviews show why it matters:

• The Breathe review works out that a 60 mL bottle at the label's 1 mL serving would last roughly two months, while the page's "30-day supply" framing assumes an optional second daily serving.
• The Liv Pure review lists 60 capsules per bottle with a 30-day supply at the label serving, and calculates the price per day from the 2-capsule serving.

The lesson is simple: a bottle of 60 capsules lasts 30 days at 2 a day, 20 days at 3 a day and 60 days at 1 a day. The price per bottle stays the same, but your monthly cost changes a lot.

How does bundle pricing (1, 3 or 6 bottles) change the math?

Most of the offers we audit sell tiers: one bottle, three bottles and six bottles, with a lower price per bottle as you commit to more. The catch is that you pay for all the bottles up front, so the discount is only real if you would have used them anyway.

Real examples from our price tables, all from the sales pages as we read them:

• The ProDentim review lists $69, $59 and $49 a bottle for 1, 3 and 6 bottles, which is $69, $59 or $49 a month since a bottle is one month. It also notes that the sales page's price table contains follow-up offers priced as low as $29 a bottle that appear after a first purchase.
• The NeuroVera review lists $49, $39 and $29 a bottle, and notes that the site's shipping policy says the purchase price includes shipping.
• The iGenics review lists $59 plus $9.99 shipping for one bottle, then $49 and $39 a bottle for 3 and 6, with free shipping on the larger bundles.

Every review page has a price table with a per-month figure, so you can compare products on the same basis. If you are browsing by condition, start from a category page or the full list of reviews.

Worked example with illustrative numbers

The numbers below are illustrative and made up. They do not describe any real product. Assume a capsule product with 60 capsules per bottle, a label serving of 2 capsules a day (so 30 days per bottle), and these prices:

Now change the assumptions, still with made-up numbers:

• Sales tax. If a 7 percent tax applied to the 6-bottle order, the total would be $314.58, which is about $52.43 a month. Tax rules vary by state, so check the final order page.
• One add-on. If you accepted a one-time $9.99 add-on with the 6-bottle order, spread over 6 months it adds about $1.67 a month.
• Different dose. If you take 3 capsules a day, a bottle lasts 20 days. At $49 a bottle (the 6-bottle price), that is $2.45 a day, or $73.50 a month, not $49.
• Unfinished bottles. If you stop after 3 months and never use the other 3 bottles, you paid $294 for 90 days of use, which is $98 a month. Check the refund window before you rely on the bulk discount.

The same product can cost $49 or nearly $100 a month depending on choices that are not on the price tag.

What about shipping, taxes, upsells and add-ons?

These are the pieces that break "the price on the page". The FTC's consumer guidance notes that if you have to pay for shipping or fees to get a "free" offer, it is not really free, so read the total, not the headline.

Extra offers are their own line. The FTC's enforcement policy statement describes an upsell as a second solicitation for an additional product after you complete a first transaction. On supplement order forms, that can be a bonus bottle deal, a digital guide or a shipping protection fee. Our LeanBiome review records an optional paid shipping add-on that can be declined, and our Spartamax review records an exit offer and cross-sold guides. Add-ons you decline cost nothing, add-ons you accept raise your total, so count them in.

What if it is a subscription?

An auto-ship plan changes the question from "what is my cost this month" to "what will I be charged each month, and how do I stop it". Look for the billing interval, the price after any promotional rate, and the cancellation method before you enter a card. Our guide to ClickBank refunds explains how to look up an order and ask for a refund if something goes wrong, and our article on free trials and auto-ship charges goes deeper on subscriptions.

If a review says the checkout is a one-time payment, that is the price for the bottles you chose. It still does not tell you how long they last, so do the days-per-bottle step yourself.

A five-minute checklist before you buy

1. Find servings per bottle and the label serving size. Compute days per bottle.
2. Write the total due today, including shipping, and note whether tax is added.
3. Decline or count every add-on. Uncheck anything pre-selected that you did not choose.
4. Divide by days, multiply by 30. Compare with two or three other products on that same number.
5. Ask whether you would really finish the bulk order in time, and note the refund window.
6. Keep the receipt and a screenshot of the order page.

The FDA notes that it is not authorized to approve dietary supplements for safety and effectiveness before they are marketed, so price is not a guide to quality either way. Talk to a doctor or pharmacist before starting a supplement, especially if you take medicine or have a health condition.

FAQ

How do I calculate cost per serving of a supplement?

Divide the total you paid by the number of servings you get. Servings per bottle is on the Supplement Facts panel. For a bundle, multiply servings per bottle by the number of bottles.

Is buying 6 bottles cheaper than buying 1?

Per bottle it usually is, but only if you will finish them. If you stop early, the unused bottles raise your true cost, so check the refund window first.

Is a "30-day supply" always 30 days?

No. It depends on the label serving and how many servings you take. Compare the servings per container with your daily dose to see how long a bottle lasts.

Do our reviews show the monthly cost?

Yes. Each review has a price table with the per-month cost by bundle, plus notes on shipping and extras, as far as the order form showed them. See how we review for what we check.

The example table uses made-up numbers for teaching. This article is general information, not medical advice.