ABOUT
About Pattobako
Pattobako is a collection of free tools for quick, everyday calculations.
Who makes Pattobako?
Pattobako creates and operates these tools. They grew from everyday tasks such as comparing package prices and checking changes in text. We publish small tools that can solve those tasks directly.
For example, we check a unit-price comparison by separately dividing each price by its amount and calculate percentage differences before rounding. Guides also show how changing an assumption, such as using only part of a package, can change the decision. Hypothetical prices are examples, not claims of purchases or product tests.
What we are building
Some calculations are too small for a spreadsheet but too useful to do in your head. Pattobako puts those calculations in simple pages you can open and use right away, with no account or sign-in.
How the calculators work
Dates, prices, text, and other values entered into our tools are normally processed in your browser. We do not receive or store those inputs.
When you choose to share a result from a supported calculator, the values needed to recreate that calculation are added to the shared URL. Text and raffle entries are not included in shared URLs.
Our approach
We focus on clear answers, fast pages, and a good mobile experience. We want a visitor from search to be able to finish a calculation or conversion without unnecessary steps.
How we create and review tools and guides
We use generative AI, including Codex, to help write code and draft content. We do not treat generated answers as automatically correct. Our review process combines recalculating examples, automated tests, and browser checks. For guides, we also look for missing conditions, confusing wording, and instructions that do not match the calculator.
We choose everyday comparisons and calculations that can be completed in a browser. For each calculator, we review the formula, the inputs, the rounding behavior, example results, and feedback for invalid entries.
Our shopping guides explain how to read a promotion, work through the math, and use the result in a decision. They link to a calculator so you can apply the method to your own price or quantity instead of relying on a generic example.
Store terms, taxes, point programs, and rounding rules can vary. If a result matters to a purchase or another important decision, check the applicable official terms as well.
Found a mistake or something hard to use? Contact us with the page and a description of the problem. You do not need to send personal or confidential text.