This product was not featured by Product Hunt yet. It will not be visible on their landing page and won't be ranked (cannot win product of the day regardless of upvotes).
468 free online calculators covering tax, finance, health, unit conversion, math, date, everyday life, and programming. No ads, no sign-up, no popups. Every calculation runs client-side — your data never leaves your browser. Built with Next.js SSG for sub-second load times. Japanese and English bilingual support. New calculators added weekly based on user requests. From BMI and loan payments to hex converters and regex testers — if you need to calculate it, it's probably here.
I started building Keisan Tools when I needed a Japanese tax calculator and couldn't find a good free one online. One calculator turned into 10, then 50, then 468.
Every calculator:
- Loads in under 1 second (static site generation)
- Runs entirely in your browser (zero server calls)
- Has no ads, no sign-up, no premium upsell
I add about 5 new calculators every week based on requests. Recent additions: pension estimator, household budget planner, mortgage prepayment simulator.
What calculator do you wish existed but can't find online? I'll build it and tag you when it's live.
Keisan Tools was submitted on Product Hunt and earned 2 upvotes and 1 comments, placing #94 on the daily leaderboard. 468 free online calculators covering tax, finance, health, unit conversion, math, date, everyday life, and programming. No ads, no sign-up, no popups. Every calculation runs client-side — your data never leaves your browser. Built with Next.js SSG for sub-second load times. Japanese and English bilingual support. New calculators added weekly based on user requests. From BMI and loan payments to hex converters and regex testers — if you need to calculate it, it's probably here.
On the analytics side, Keisan Tools competes within Productivity and Developer Tools — topics that collectively have 1.2M followers on Product Hunt. The dashboard above tracks how Keisan Tools performed against the three products that launched closest to it on the same day.
Who hunted Keisan Tools?
Keisan Tools was hunted by Tatsuya Mizuno. A “hunter” on Product Hunt is the community member who submits a product to the platform — uploading the images, the link, and tagging the makers behind it. Hunters typically write the first comment explaining why a product is worth attention, and their followers are notified the moment they post. Around 79% of featured launches on Product Hunt are self-hunted by their makers, but a well-known hunter still acts as a signal of quality to the rest of the community. See the full all-time top hunters leaderboard to discover who is shaping the Product Hunt ecosystem.
For a complete overview of Keisan Tools including community comment highlights and product details, visit the product overview.
Tatsuya Mizuno