Contents
Compare an imaginary 900 g pack at ₩7,200 with a 1.2 kg pack at ₩9,000. The smaller pack costs less at checkout, while the larger one costs less for the same quantity. Add the amount you might throw away, and the choice can change again.
- Compare
- Products of similar type and quality
- Use one unit
- For example, 100 g or 100 mL
- Example prices
- Invented for explanation, not current offers
- Sources checked
- 7 October 2026 · KCA and aT
Put the packs on the same scale
Unit price answers a simple question: what does the same amount cost? Divide the price by the weight in grams and multiply by 100 to find the cost per 100 g. Convert 1.2 kg to 1,200 g first.
Pack A costs ₩800 per 100 g; pack B costs ₩750. B is ₩50, or 6.25%, cheaper per 100 g relative to A. You still pay ₩1,800 more at checkout.
900 g / ₩7,200
₩800per 100 g1,200 g / ₩9,000
₩750per 100 gWhat if you leave 200 g unused?
Suppose you buy B but use only 1,000 g and discard 200 g. Your spending per 100 g actually consumed is ₩9,000 ÷ 1,000 × 100 = ₩900. That is more than the ₩800 for consuming all of A.
This does not make large packs inherently poor value. It shows why the amount used matters. To keep B’s cost per amount consumed at ₩800 per 100 g or less, you must use at least 1,125 g—discarding no more than 75 g.
Consider household size, storage space, whether freezing is suitable and the instructions after opening. A low unit price helps only if the pack fits your routine.
Count what you receive in a multi-buy
An imaginary two-for-one offer gives you two 500 g packs for ₩6,000: 1,000 g altogether, or ₩600 per 100 g. Use the actual total quantity and payment rather than the word “free”.
For coupons, check the minimum spend, eligible products and maximum discount. Include extra items bought to qualify, along with delivery or travel costs, in your total.
Equal weight is not equal quality
Milk and a flavoured milk drink, concentrate and a diluted product, or prepared and unprepared ingredients may differ beyond their weight. Ingredients, grade and edible portion matter too.
Decide what product you want before comparing similar alternatives. For items sold by the piece, also check whether individual sizes differ.
Where to look up real prices
Korea Consumer Agency’s Champrice provides surveyed prices for selected products. Survey dates, promotions and the sample of stores can affect the figures; a survey is not a promise of today’s checkout price.
aT KAMIS lists agricultural, livestock and fishery prices with product, grade and unit information. Keep wholesale separate from retail and compare equivalent quantities.
Use official surveys for context, then confirm the price in the actual store or checkout. Being below a surveyed average does not establish that an offer is the cheapest available.
Start with one regular purchase
Note the size and price of one item you buy often. Calculate a common unit price and ask whether you can use the whole pack. There is no need to memorise every shelf.
If the unit-price saving is small, include the extra spending and travel needed to shop elsewhere. What matters is the total cost of the basket you will actually use.
Frequently asked questions
Can I compare 100 g directly with 100 mL?
No. Weight and volume are different units. Use the same type of unit unless you have a valid product-specific conversion.
Should I always pick the lowest unit price?
Also check product comparability, how much you will use, storage needs and the total payment.
Summary
Compare equal quantities before looking at the discount percentage. Convert the final price to a per-100 g or per-100 mL figure, then check how much you can actually use and store. Include coupon conditions and likely waste when deciding whether a larger pack is better value for you.
