Unit Price Calculator (compare cost per gram, oz, count)
Enter price and quantity for each item. The calculator divides to give cost per unit and highlights the best deal so you can shop on real value, not just sticker price.
How it works
Why unit price matters
Sticker prices lie. A 'family size' bag of chips at $5.99 sounds like a deal until you compare against the regular bag at $3.49 — the family size might be 32% bigger but cost 71% more, making it worse value per chip. Unit price (price ÷ quantity) cuts through marketing tricks and shows you what each gram, ounce, or item actually costs.
Most US grocery shelves now display unit price below the regular price, but it's often in tiny print and inconsistent units (some per ounce, some per pound, some per item). This calculator lets you compare with consistent units of your choice.
Common gotchas
Unit mismatch: comparing 'per gram' to 'per ounce' silently inflates one number by ~28×. Make sure all items use the same unit before comparing — convert if needed.
Volume vs weight: liquid soap might be priced per fluid ounce while bar soap is per ounce (weight). Convert to a consistent measure (or compare 'per use') for accurate comparisons.
Bulk fallacy: bulk packs aren't always cheaper. Stores sometimes price the larger size higher per unit, betting on customers' assumption. Always check.
Coupons and sales: they change unit price. If one item has a $1 off coupon, subtract $1 from its price before comparing.
Beyond grocery shopping
Subscription comparisons: monthly versus annual versus 3-year. Convert all to monthly cost. Annual is often 15-20% cheaper than monthly when paid up front.
Cell phone plans: divide total price by months in contract. Or by GB of data, or by minutes of talk if those are the limiting resource.
Cloud storage / SaaS: cost per GB, per user, per request. Hidden tier fees can flip what looks cheap into the more expensive option once you exceed the free tier.
Frequently asked questions
›Why isn't 'per pound' a default?
We let you pick because needs vary — grams, ounces, pounds, count, gallons. Just keep the unit consistent across items.
›What if I'm comparing different sized packs of the same product?
Same answer — enter price and quantity in the same unit for each, and the calculator does the per-unit math.
›Does this account for taxes?
No. Use post-tax prices if your jurisdiction taxes differently for different items, or pre-tax if not.
›Can I save my comparisons?
Not yet. Refreshing the page resets the list.
›What's a 'fair' precision?
We display up to 4 decimal places. For most groceries 2-3 decimals is enough; per-fluid-ounce or very low-cost items benefit from 4.
›Should I always pick the cheapest unit price?
Usually yes for fungible goods. But quality, brand preference, perishability (will you use it before it expires?), and storage space matter for some categories.
›What about quantity discounts?
If an item has a 'buy 2 for $5' deal, calculate price = 2.50 and quantity = 1 to compare apples-to-apples with single-pack pricing.
›Does the data leave my browser?
No. All math runs locally.
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