About conv.day

Our Mission

conv.day was created with a simple goal: provide the fastest, most private, and easiest-to-use collection of online calculators and unit converters. Every calculation runs entirely in your browser — no data ever leaves your device.

Technology

Built with Astro and deployed on the Cloudflare global edge network, conv.day delivers sub-second page loads with zero JavaScript framework bloat. All calculations use client-side JavaScript for instant results and maximum privacy. The site supports 5 languages (English, Polish, German, Spanish, French) with dedicated localized URLs for each tool.

What We Offer

• Date & Calendar tools — date difference, working days, week numbers, vacation planner
• Finance calculators — salary (brutto/netto), VAT, compound interest, currency converter, mortgage
• Unit converters — length, weight, temperature, area, speed, data storage, historical units
• Health tools — BMI & calorie calculator, medication dosage estimator
• Math utilities — percentage & margin calculator, download time estimator, time zone converter

Privacy & Trust

Your data stays with you. All calculations are performed locally in your browser. We use Google Analytics for aggregate traffic analysis and Google AdSense for advertising, both of which may use cookies as described in our Privacy Policy. We never collect, store, or process your personal calculation inputs.