Lab
Lab: How We Normalize Price per Ounce
The exact formula we use so pack size can’t fool you, plus when history cannot be shown.
Why package price misleads
A $10 bag and a $13 bag cannot be compared until you know how much fruit each one holds. Price per ounce puts every listing on the same scale: what you pay for one ounce (28.35 g) of the product as sold. It is the number we use to compare package sizes of dates, and the reason a larger pack can be clearly cheaper by weight even when its checkout total is higher.
The formula
Price per ounce = listed price ÷ (net weight in grams ÷ 28.3495)
Weights are stored in grams and converted with 1 oz = 28.3495 g. Pounds and kilograms are converted to grams first (1 lb = 453.59 g, 1 kg = 1,000 g). The result is displayed to the cent, with its currency, for example “1.08 USD/oz”.
Worked examples
The figures below are illustrative arithmetic, not live prices.
| Listing | Price | Net weight | Price per ounce |
|---|---|---|---|
| Small bag | $10.00 | 8 oz (226.8 g) | $1.25 |
| Large bag | $13.00 | 12 oz (340.2 g) | $1.08 |
| Family pack | $24.00 | 32 oz (907.2 g) | $0.75 |
The large bag costs $3 more than the small one at checkout, yet each ounce is about 17 cents cheaper. That gap is invisible if you only compare the package price.
Which offers we compare
- Verified offers only. An offer needs a product identity, a merchant URL, a positive price, a valid currency and the commercial verification checks before it can be shown as a current price.
- Fresh prices. Current-price highlights use offers checked within the last 72 hours. Older observations stay in the price history but are not presented as today’s price.
- One currency at a time. Different currencies are never mixed in a single comparison.
- Known weight. A unit price appears only when the net weight is known and comparable.
- Nothing is hidden. Higher-priced verified offers stay visible. A “best price” label needs at least two verified offers of the same product; with one, the label reads “Verified current offer”.
What the number leaves out
Shipping and tax
Price per ounce uses the item price. Shipping is shown separately when it is known, and when it is unknown we make no claim about the total cost. Add shipping yourself before deciding between merchants.
Pits
The printed weight of an unpitted bag includes the pits, so you pay for stones as well as fruit. To compare unpitted with pitted dates, adjust for the pit share:
Price per ounce of fruit ≈ price per ounce ÷ (1 − pit share)
Pit share varies with variety and size, so there is no single correct figure. As an illustration only, if pits made up 10% of the weight, an unpitted bag at $1.25 per ounce would cost about $1.39 per ounce of fruit. Weigh a handful of pits from your own bag for a better estimate.
Quality
The cheapest ounce is not always the best buy. A very soft, fresh pack and a dry, firm one are different products; see the moisture and texture test for how we describe the difference, and the guide to buying dates online for what else to check on a listing.
Coupons and subscriptions
Coupon codes, loyalty prices and subscription discounts change from day to day. If you have one, apply it to the listed price and run the same formula.
Check any listing yourself
- Find the net weight on the label or listing, not the shipping weight.
- Convert it to ounces: grams ÷ 28.3495, pounds × 16, kilograms × 35.274.
- Divide the price by the ounces.
- If one product is pitted and the other is not, adjust for the pit share as above.
- Compare like with like: the same variety and form (whole, pitted, gift box).
The price-per-ounce calculator does steps 2 and 3 for you.