Unit Price Comparison: worked example
| Price of item A | $4.79 |
|---|---|
| Quantity in item A | 16 |
| Price of item B | $8.99 |
| Quantity in item B | 32 |
| Unit price of item A | 0.299 |
| Unit price of item B | 0.281 |
| Saving from the cheaper item | 6.2% |
Unit Price Comparison: changing Price of item A
| Price of item A | Unit price of item A | Unit price of item B | Saving from the cheaper item |
|---|---|---|---|
| $3.83 | 0.239 | 0.281 | 14.8% |
| $4.31 | 0.269 | 0.281 | 4.1% |
| $4.79 (example) | 0.299 | 0.281 | 6.2% |
| $5.27 | 0.329 | 0.281 | 14.7% |
| $5.75 | 0.359 | 0.281 | 21.8% |
Unit Price Comparison: compare input ranges
| Input | Tested from | To | Unit price of item A: low input | Unit price of item A: high input | Swing |
|---|---|---|---|---|---|
| Quantity in item A | 14 | 18 | 0.342 | 0.266 | 0.076 (25%) |
| Price of item A | $4.31 | $5.27 | 0.269 | 0.329 | 0.06 (20%) |
| Price of item B | $8.00 | $10 | 0.299 | 0.299 | 0 |
| Quantity in item B | 29 | 35 | 0.299 | 0.299 | 0 |
Unit Price Comparison: individual input comparisons
| Input | Value | Unit price of item A | Unit price of item B | Saving from the cheaper item |
|---|---|---|---|---|
| Price of item A | $3.83 | 0.239 | 0.281 | 14.8% |
| $4.31 | 0.269 | 0.281 | 4.1% | |
| $4.79 | 0.299 | 0.281 | 6.2% | |
| $5.27 | 0.329 | 0.281 | 14.7% | |
| $5.75 | 0.359 | 0.281 | 21.8% | |
| Quantity in item A | 13 | 0.368 | 0.281 | 23.8% |
| 14 | 0.342 | 0.281 | 17.9% | |
| 16 | 0.299 | 0.281 | 6.2% | |
| 18 | 0.266 | 0.281 | 5.3% | |
| 19 | 0.252 | 0.281 | 10.3% | |
| Price of item B | $7.00 | 0.299 | 0.219 | 26.9% |
| $8.00 | 0.299 | 0.25 | 16.5% | |
| $9.00 | 0.299 | 0.281 | 6.1% | |
| $10 | 0.299 | 0.313 | 4.2% | |
| $11 | 0.299 | 0.344 | 12.9% | |
| Quantity in item B | 26 | 0.299 | 0.346 | 13.4% |
| 29 | 0.299 | 0.31 | 3.4% | |
| 32 | 0.299 | 0.281 | 6.2% | |
| 35 | 0.299 | 0.257 | 14.2% | |
| 38 | 0.299 | 0.237 | 21.0% |
Unit Price Comparison: combined input changes
| Price of item A / Quantity in item A | 13 | 16 | 19 |
|---|---|---|---|
| $3.83 | 0.295 | 0.239 | 0.202 |
| $4.31 | 0.332 | 0.269 | 0.227 |
| $4.79 | 0.368 | 0.299 | 0.252 |
| $5.27 | 0.405 | 0.329 | 0.277 |
| $5.75 | 0.442 | 0.359 | 0.303 |
Unit Price Comparison: which assumptions move the result?
Unit Price Comparison: values and definitions
| Quantity and definition | Value used |
|---|---|
| Price of item A | $4.79 |
| Quantity in item A — Ounces, grams, sheets or any unit. Use the same unit for item B. | 16 |
| Price of item B | $8.99 |
| Quantity in item B | 32 |
| Unit price of item A | 0.299 |
| Unit price of item B | 0.281 |
| Saving from the cheaper item | 6.2% |
Unit Price Comparison: half and double Quantity in item A
| Quantity in item A | Unit price of item A |
|---|---|
| 8 | 0.599 |
| 16 | 0.299 |
| 32 | 0.15 |
The cheaper unit price is not the better buy if the food spoils, if you have no place to store it, or if quality differs. Store brands and sales change the comparison. Shelf labels show unit prices, but different items may use different units.
Bulk stores may require membership fees that offset savings.
Unit Price Comparison: formula
Enter the price and quantity for each package, using the same unit for both, such as ounces, sheets or count. If one is in pounds and the other in ounces, convert first. Include the price after any discount or coupon that applies to that item, since the unit price compares what you pay.
The tool works for groceries, household goods and anything sold by size.
Common error: Buying the big size and letting part of it spoil. A saving of 6 percent disappears if you throw away a tenth of the product.
Everyday Money calculators: TV Size Calculator, Percentage Calculator, Percentage Change Calculator, Discount Calculator, Tip Calculator, Salary to Hourly Calculator.
The bigger pack is not always the cheaper one. Compare price divided by quantity, in the same unit. A 16 ounce jar at $4.79 costs about 29.9 cents an ounce, and a 32 ounce jar at $8.99 costs about 28.1, so the large one saves roughly 6 percent.
The gap can be small, and sometimes a sale on the small size beats the bulk price outright.
Make sure both quantities use the same unit. Weight in ounces against volume in fluid ounces, or against a count of sheets, gives a comparison that is not real.
Check discounts with the discount calculator, convert units with the unit-conversion pages, and compute sales tax on the sales tax page. The percentage change calculator shows savings between two prices. For household budgets, the student budget page helps set targets.
Is the bigger package always cheaper per unit?
Often but not always. Promotions on smaller sizes, and larger sizes with premium pricing, can reverse it, so compare the unit prices.
When is the cheaper unit price not worth it?
When you will not use the item before it expires, when it costs storage space you do not have, or when quality is worse.
How do I compare different units?
Convert both to the same unit first, such as ounces, so the unit prices are on the same basis.