Browser-only cost tool
The price on the jar tells you what one purchase costs. It does not tell you what your routine costs. Enter a price and a net size, say where on your body the product goes and how often, and this works out the cost per application, the cost per month and year, and how long one container should actually last.
Coverage sources reviewed August 8, 2026
Run the numbers
Coverage is the input almost every price comparison skips. Two people can buy the same jar and one of them empties it more than thirty times faster, because one is treating a face and two hands and the other is treating a whole body twice a day. Set the body areas and frequency once, then set the layer separately for each product, because a dense balm and a pump lotion are not used in the same quantity.
7 is once a day. 14 is morning and night. 3 is roughly every other day.
Products you are comparing
Use the net quantity printed on the package, not the shipping weight on a marketplace listing. If a product is labeled in fluid ounces it is measuring volume, not weight, so treat that comparison as rough. Set the layer per product: this is where a dense balm separates from a lotion you use by the handful.
Up to 4 products.
Thin layer is 0.5x, Standard coverage is 1x, Generous layer is 1.5x a measured finger-tip unit.
Result
That covers roughly 1,401 cm2 of skin and takes 2.5 g of product at a standard layer, or proportionally less or more at the layer you set per product. You are doing this 7 times a week.
| Product | Per use | Cost per use | Per month | Per year | One container lasts | Cost per oz |
|---|---|---|---|---|---|---|
| LotionStandard coverage | 2.45 g | $0.259 | $7.89 | $94.70 | 3.0 months93 applications | $3.00 |
| BalmLowest yearlyThin layer | 1.23 g | $0.216 | $6.58 | $78.91 | 2.3 months69 applications | $5.00 |
Over a year of this routine, Balm works out $15.78 cheaper than Lotion, and you would buy about 5.3 containers of it rather than 3.9. It also costs $5.00 an ounce against $3.00, so the shelf comparison points the other way.
These are planning estimates from published coverage figures, not measurements of your own use, and they say nothing about how any product will perform on your skin. One finger-tip unit is 0.5 g covering 286 cm2, a mean with real variation around it. Everything runs in your browser and nothing you type is sent or saved.
The comparison trap
Weight against volume
FDA labeling rules put the net quantity of a liquid cosmetic in fluid ounces, a measure of volume, and the net quantity of a solid, semi-solid, or viscous cosmetic in ounces of weight. A 16 fl oz pump lotion and a 4 oz balm are counted on two different scales, so dividing price by that number compares nothing.
Package against contents
Marketplace listings frequently show an item or shipping weight that includes the jar, the lid, and sometimes the box. A heavy glass jar can add several ounces of nothing you can put on your skin. The number you want is the net quantity of contents on the package itself.
Ounces against applications
A thick balm and a thin lotion are not applied in the same quantity, and nobody applies either one to a fixed abstract ounce. What you spend is grams on skin multiplied by how often you do it, which is a different ranking from price per ounce more often than people expect.
Worked example
Routine one
Face and neck is 2.5 finger-tip units and two hands are 2.4, so 4.9 units in total. At half a measured unit, which is closer to how a rich cream is used in practice, that is about 1.2 g per application, or roughly 8.6 g a week.
Routine two
Every region added together is 40.2 finger-tip units, so a full measured application is about 20 g. Twice a day is roughly 40 g daily and 281 g a week. This is the level at which a rich single-ingredient product becomes a genuinely different spending decision.
Neither routine is wrong. The point is that a jar-lifespan claim or a value verdict quoted without a body area attached is not a fact about the product, and most people who feel a rich moisturizer is expensive are mentally pricing routine two while actually running something closer to routine one. Targeting the rich product at the zones that need it, and using something lighter elsewhere, is a cost decision as much as a texture one.
What the tool cannot do
The finger-tip unit is a mean with real spread around it. Long and Finlay measured 286 cm2 of coverage per unit with a standard deviation of 80, and found 312 cm2 in males against 257 cm2 in females. Hand size, product texture, how damp your skin is, and how thoroughly you rub in all move the real figure. Treat the output as the right order of magnitude rather than a precise forecast.
The thin, standard, and generous multipliers are our adjustment, not a published measurement. They exist because a measured finger-tip unit describes a full covering layer, and plenty of people use a dense balm far more sparingly than that. If you want to know your own number, weigh the jar, use it normally for two weeks, and weigh it again.
Cost also says nothing about whether a product suits your skin, and a cheaper container you abandon in a drawer is not the cheaper option. This calculator compares spending on a routine you have already decided to run. It offers no safety score, no suitability verdict, and no medical guidance.
Common questions
It depends almost entirely on how much skin you cover. Using the published finger-tip unit figures, face and both hands at a thin layer once a day works out to roughly 1.2 g per application, so a 4 oz jar (about 113 g) lasts around three months. Move the same jar to whole-body use twice a day and it is gone in under a week. Any jar-lifespan number quoted without a body area attached is close to meaningless.
Only when both products are labeled in the same kind of unit and you use the same amount of each. FDA labeling rules put the net quantity of a liquid cosmetic in fluid ounces, which measures volume, and the net quantity of a semi-solid balm or cream in ounces of weight. Comparing those two numbers directly is a unit error. Cost per application avoids the problem because it starts from grams of product on a measured area of skin.
A finger-tip unit is the amount of product squeezed from a 5 mm nozzle along an adult index finger, from the last joint crease to the tip. Long and Finlay measured it in 1991 and found one unit covers about 286 cm2 of skin. A follow-up letter in 1992 pinned it at 0.5 g. It was developed to make topical steroid dosing understandable, and it works here purely as a coverage yardstick for how far a gram of any leave-on product goes.
No, and that is the main thing this calculator exists to show. A denser product used in thinner layers can cost less per application than a cheap tub used by the handful, and the yearly figures can invert against the shelf price. The comparison only becomes real once you fix the body areas, the layer thickness, and the frequency, which is what the inputs above do.
No. Every figure is computed in your browser as you type. Nothing is submitted, stored, or saved, and there is no signup.
Price the Misun jars
Take the current price and the net quantity of contents from the listing, drop both into the table above, and set the areas you would actually use it on. Amazon shows the current package, price, availability, delivery options, and customer reviews.
$19.97
100% Natural Whipped Beef Tallow Cream
$17.97
Dense Beef Tallow Balm
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