home/buyers

Buyer tools · 3 free calculators

The cheaper price isn't always the better deal.

Sticker price hides two things: how long a product actually lasts, and what unit you're really paying for. These two calculators strip both away and show the number that actually matters — before you click buy.

Nothing leaves your browser
No account, ever
Instant results
Free, no limits

The three tools

What each one calculates — and when to use it

Open any card to see exactly what it computes and the problem it solves.

01 Cost Per Use Calculator Buying once vs. buying often

Enter price and expected uses for up to four options — including upkeep costs like batteries, refills, or dry cleaning. The calculator divides total cost by total uses and ranks every option by real cost, not sticker price.

Price ÷ usesUpkeep includedUp to 4 optionsBest-value winner
÷ uses
A $300 pair worn 200 times can cost less per wear than a $60 pair worn 15 times.
Open Cost Per Use Calculator →
02 True Unit Price Comparator

Enter price, size, and unit for any two package sizes — even in different measurements. The calculator converts both to a shared unit and shows which one is actually cheaper per ounce, gram, or liter.

Mixed units OKPer oz / g / literBulk-size reality check
/ oz
The "value size" isn't always the better unit price. This is how you check.
Open True Unit Price Comparator →
03 Smart Return & Capital Dashboard

Log what you bought and each retailer's return window. The dashboard tracks every deadline and totals the capital sitting in items you could still send back — so a return window never quietly closes on you.

Return deadlinesCapital trackerPer-retailer windows
Money you can still get back is still your money — until the deadline passes.
Open Smart Return & Capital Dashboard →

Two different questions, two different tools

"Will this last me long enough to be worth it?" That's Cost Per Use — for comparing items of different quality or durability, like a cheap umbrella that breaks in a month against an expensive one that lasts five years.

"Is this pack actually the better deal?" That's the Unit Price Comparator — for comparing the same product in different sizes, where the only real question is price per unit, nothing else.

Mix them up and you'll get an answer to the wrong question. A bulk pack of something you'll use once isn't a deal at any unit price.

Worth knowing

Four pricing tricks worth checking before you buy

SIZE

"Value size" sometimes means a worse unit price

Bulk packaging carries its own cost, and not every retailer passes the saving on. Checking the actual unit price takes seconds and occasionally proves the smaller pack wins.

UNITS

Different units make comparisons disappear on purpose

One brand prices per fluid ounce, another per gram, a third per "serving." Converting everything to one shared unit is the only way to see which is actually cheaper.

UPKEEP

The sticker price is rarely the full price

Batteries, refills, subscriptions, and cleaning costs belong in the comparison, not as an afterthought discovered three months in.

LIFESPAN

Durability only matters if you'd actually use it that long

A product built to last ten years is only a better deal if you'd keep using it for ten years. Match the comparison to how you actually live, not the best-case scenario on the box.

FAQ

Common questions

Which calculator should I use?

Use Cost Per Use when comparing a cheaper item against a pricier one that lasts longer. Use the Unit Price Comparator when comparing package sizes of the same product. Use Smart Return & Capital Dashboard to track return deadlines on anything you've already bought.

Do I need to create an account?

No. Both calculators work instantly with numbers you type in. Nothing is saved, tracked, or sent anywhere.

Are these calculators free?

Yes, completely free, with no signup and no usage limits.

Why isn't the bigger pack always cheaper per unit?

Retailers don't always discount bulk sizes — sometimes the smaller pack is on promotion, or the bulk size uses a different base unit that hides the comparison. The Unit Price Comparator normalizes both to the same unit so the discount claim can actually be checked.

What counts as a "use" in Cost Per Use?

Any reasonable, consistent unit: wears for clothing, applications for skincare, loads for a kitchen appliance, months for a subscription. Pick one definition and apply it to every option you compare.

Also useful

Selling on Amazon instead?

Seller toolsProfit margin, inventory payback, and ad spend ceiling. All calculatorsThe full set of free Herminox tools on one page.
© 2026 herminox.com — independent, ad-free, private.