Interpolation Calculator

A free, browser-based interpolation calculator. Enter known data points and instantly get step-by-step results for linear, logarithmic, and double (bilinear) interpolation — all processed client-side, with no data leaving your browser.

Live site: interpcalc.com

Features

• Linear interpolation — straight-line estimate between two known points
• Logarithmic interpolation — for data that varies linearly with ln(x), e.g. pH, decibels, Richter magnitude
• Double (bilinear) interpolation — interpolates across a 2D grid using four corner values (e.g. steam tables)
• Full step-by-step working shown for every result, not just a final number
• Automatically flags results that fall outside the known data range as extrapolated
• Runs entirely in the browser — no sign-up, no server round-trip
• Multi-language support (English, Spanish, French, German, Portuguese, Italian, Japanese, Korean)
• SEO-optimized static pages (About, Privacy Policy, Terms, Contact, FAQ)

Tech Stack

• Astro — static site generation
• Tailwind CSS v4 — utility-first styling
• TypeScript for the interpolation engine
• Cloudflare Workers — deployment via Wrangler

Project Structure

/
├── public/                    # favicons, robots.txt, static assets
├── src
│   ├── components/            # HomePage, InterpolationCalculator, Field, LegalPage, ErrorPage
│   ├── i18n/                  # dictionary, language list, per-locale translations
│   ├── layouts/                # base page layout
│   ├── lib/
│   │   └── interpolation.ts   # linear, logarithmic, and bilinear interpolation logic
│   ├── pages/                 # index, about, contact, privacy, terms, 404/500
│   │   └── {de,es,fr,it,ja,ko,pt}/  # localized routes
│   └── styles/
└── wrangler.jsonc              # Cloudflare deployment config

Commands

All commands are run from the root of the project, from a terminal:

Command	Action
npm install	Installs dependencies
npm run dev	Starts local dev server at localhost:4321
npm run build	Build production site to ./dist/
npm run preview	Preview the build locally
npm run deploy	Build and deploy to Cloudflare Workers