To compare 5, 10 and 15 mL bottles, first establish that they contain the same product. Then divide the final price by the labelled volume. A larger bottle is not automatically a better choice when composition, shipping or your required quantity differs.
Check comparability first
Match the name, botanical identity, ingredients and any stated concentration. A carrier-based roll-on and an undiluted oil are not equivalent products just because both list a volume. For sample sets, check each sample's contents.
Use the labelled volume and the current offer price. Include shipping consistently for both options or show it separately. A universal number of drops per millilitre is neither needed nor assumed in this comparison.
The eoASSIST oil reference
Search for oils by name and open their reference entries.
An invented calculation
These are teaching prices in arbitrary units, not market offers. The example assumes the same product and consistent shipping treatment.
| Volume | Price | Price per mL |
|---|---|---|
| 5 mL | 600 | 600 / 5 = 120 |
| 10 mL | 1000 | 1000 / 10 = 100 |
| 15 mL | 1350 | 1350 / 15 = 90 |
A lower unit price is not the whole decision
The 15 mL option has the lowest price per mL here, but requires the highest total spend. Consider whether you need that quantity. If you are still deciding about a product, a small format may suit exploration despite a higher unit price.
Check the manufacturer's storage conditions, date information, packaging and batch details. Do not estimate use time from an invented daily consumption rate or a universal use protocol.
Keep a repeatable comparison
Record the price date, seller, exact item, volume and included costs. You can then repeat the comparison when an offer changes. Keep different products on separate rows and do not present price arithmetic as a quality assessment.
See sample comparisons, roll-on ingredients and storage after opening.
The eoASSIST oil reference
Search for oils by name and open their reference entries.