# Unit Price Comparison Calculator

- **URL:** https://codeasystem.com/calculators/everyday/unit-price-comparison-calculator/
- **Category:** everyday
- **Description:** Compare two package sizes by true price per unit and see instantly which product is the better deal.
- **Primary output:** Best value: Product B

## Inputs
- Product A; price (name: `priceA`, type: number, prefix: $, example: 4.99)
- Product A; size (name: `sizeA`, type: number, example: 12)
- Product A; unit (name: `unitA`, type: text, example: oz)
- Product B; price (name: `priceB`, type: number, prefix: $, example: 6.49)
- Product B; size (name: `sizeB`, type: number, example: 16)
- Product B; unit (name: `unitB`, type: text, example: oz)

## Outputs
- Best value: Product B
- Product A ($4.99 ÷ 12 oz): $0.42 per oz
- Product B ($6.49 ÷ 16 oz): $0.41 per oz
- Product B is cheaper by: 2.45%

## Formula / methodology
```
Unit price = price ÷ package size
Cheaper by % = (higher − lower) ÷ higher × 100
```

Each product’s price divided by its contents yields the honest per-unit cost that shelf tags obscure. We compare the two unit prices directly and report how much cheaper the winner is relative to the loser, expressed as a percentage of the worse deal.

## Assumptions & limitations
- Both sizes contain comparable goods (same brand tier or interchangeable substitute).
- Units match; convert grams↔ounces first if they differ.
- Prices exclude coupons and loyalty discounts unless you fold them in.

## How to use
1. **Enter product A**; Shelf price and net contents, using the unit printed on the package (oz, g, sheets, loads…).
2. **Enter product B**; Same fields for the rival size or brand; keep units consistent for a valid comparison.
3. **Read the verdict**; The best-value row names the winner and quantifies the gap as a percentage.

## Example
A $4.99 12 oz jar costs about 41.6¢ per ounce while a $6.49 16 oz jar runs about 40.6¢; Product B wins by roughly 2.45% despite costing $1.50 more at the shelf.

Result for these inputs:

```
Best value: Product B
```

## About this calculator
### Bulk is usually cheaper; until it isn’t

Packaging economics favor big boxes, so per-unit prices fall with size most of the time. But promotions invert the rule constantly: a couponed small size regularly beats an uncouponed bulk one. Always run the numbers.

### Mind the shrink ray

Manufacturers quietly cut contents while holding price; 16 oz jars becoming 14.5 oz overnight. Comparing today’s unit prices against what you paid last quarter exposes shrinkflation instantly.

### The spoilage asterisk

Per-unit savings evaporate if the extra quantity spoils. Bulk wins only for goods you reliably finish before expiry; otherwise the cheaper sticker is the more expensive purchase.

## FAQs
### Are store shelf tags reliable?

Mostly; many jurisdictions mandate unit pricing; but formats differ (some show per-pound, some per-piece). Computing your own keeps comparisons apples-to-apples.

### What if the units differ, like oz versus grams?

Convert first: 1 oz ≈ 28.35 g. Our converter tools handle it, then bring both values back here in the same unit.

### Does this work beyond groceries?

Anything sold in quantities: paper towels, paint, subscription plans priced per seat, even gasoline across stations.

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Last updated: 2026-08-23 · Version: 1.0.0 · [HTML version](https://codeasystem.com/calculators/everyday/unit-price-comparison-calculator/)