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About
Reckon is a precision unit converter for Android. Twelve categories (length, weight, volume, temperature, time, cooking, energy cost, tire pressure, body temperature, pace, percentage, and a set of date tools) are free forever. One $2.99 unlock adds 31 more specialist, engineering, and scientific categories, plus deeper sub-modes like Cooking Density, Radioactivity Decay, and historical currency rates, conversion history, and favorites. Every screen offers three keypads (Basic with expression entry, Scientific, and Numeric) you can switch on the fly, and any result can be copied with a long-press. Live currency conversion, now with historical rates back to 1999, is a Pro category and the only feature that ever uses the network; every other category works fully offline. Japanese traditional units (shaku, sun, ken, ri, kan, monme, tsubo, jō, shō, gō, koku) are first-class throughout, not bolted on.
What it does
- 43 categories spanning everyday, specialist, engineering, and scientific units
- Three keypads (Basic, Scientific, Numeric) with expression entry and per-screen switching
- Japanese traditional units throughout
- Currency with a three-tier live provider chain (USD-pinned) plus historical rates, fetched only on demand
- Fully localized in 20 languages
- No ads, no account, no analytics
What you get free, and what the $2.99 unlock adds
Free
- Length, Weight, Volume, Temperature, Time, Cooking, Energy Cost, and Date tools
- New free categories: Tire Pressure, Body Temperature (with fever annotations), Pace ↔ Speed, and Percentage
- Date tools: age from date of birth, days between dates, date ± N days
- Three keypads (Basic with expression entry, Scientific, and Numeric), switchable per screen, with a default in Settings
- Single or multi-unit display; long-press any result to copy it; Light / Dark / System theme
Pro · $2.99 one-time
- Area, Speed, Energy, Power, Pressure, Fuel Economy, Data, Frequency, Angle, Base / Numeric, SI / IEC Prefix
- Engineering set: Force, Torque, Density, Sound, Concentration, Flow Rate, Concrete & Construction, HVAC
- Scientific set: Heat Density, Moment of Inertia, Illuminance, Magnetism, Electric Charge, Radiation (with isotope decay and half-life), Astronomical Units
- Pixel Density & Resolution, Survey & GIS, and a Cooking Density sub-mode with per-ingredient tables
- Clothing Size and Shoe Size (US / UK / EU / JP)
- Live Currency with a three-provider failover chain and 24h cache, plus historical rates back to 1999
- Last 50 conversions in history; up to 20 favorites
Languages
Reckon is fully localized in 20 languages: English, Chinese (Simplified), Chinese (Traditional), Dutch, French, German, Hindi, Indonesian, Italian, Japanese, Korean, Polish, Portuguese (Portugal), Portuguese (Brazil), Russian, Spanish (Spain), Spanish (Latin America), Thai, Turkish, Vietnamese.
Accuracy and limitations
Reckon's Currency category shows daily reference exchange rates from public providers (primarily the European Central Bank feed), not live interbank or trading rates, and it caches them for up to 24 hours; historical rates use the same daily-reference basis. Use them for everyday estimates and conversions, not for trading, settlement, or any decision that needs to-the-second pricing. Body Temperature shows informational status labels (such as normal, fever, or high fever) beside a reading; these are guidance only, not a medical diagnosis. Most other categories are exact unit math. Apparel sizing (Clothing and Shoe Size) maps published regional size charts; real garments vary by brand and cut, so a brand-variation note appears beneath every sizing result.
Privacy at a glance
- No personal data is collected by Reckon.
- All app data is stored on your device.
- No analytics, no telemetry, no crash reporting.
- No account is required to use the app.
Read the full Reckon privacy policy or learn about account and data deletion.
Permissions Reckon requests
- Internet
- Used only by the Pro Currency category to refresh daily exchange rates from one of three providers (api.frankfurter.dev, open.er-api.com, or cdn.jsdelivr.net), and to verify your purchase with Google Play. Every other category works fully offline.