UnitAnchor by Jason

UnitAnchor scans the page you're reading and converts units it finds — temperature, currency, energy, pressure, pixel density, area, length, weight, volume, power, shoe size, speed, fuel economy, torque, cooking, and dates/times with an explicit timezone — into whichever system you've set as your preference. Everything happens locally in your browser and what you're browsing is never sent anywhere. The only optional exception is currency conversion, which is off by default (see below).

What it converts
- Temperature: Celsius, Fahrenheit, or Kelvin.
- Currency: any ISO 4217 code you prefer, applied to amounts written in another currency on the page (opt-in; see below).
- Energy: kilojoules, joules, or kilocalories. Watt-hours, kilowatt-hours, MJ and BTU are read as energy; a battery capacity in mAh or Ah is read as energy when the page states its nominal voltage.
- Pressure: kilopascals, bar, atmospheres, PSI, hPa, mmHg, inHg, MPa or GPa.
- Pixel density: pixels per centimetre or dots per inch.
- Area: square metres or square feet.
- Length: metric (mm, cm, m, km) or US customary (in, ft, mi), with the unit following the size — 1 in shows as 2.54 cm, 39 km as 24.2 mi. Feet and inches such as 5 ft 10 in are read as one length.
- Weight: metric (g, kg) or US customary (oz, lb), with the unit following the size — 12 oz shows as 340 g, 70 kg as 154.32 lb. Pounds and ounces such as 7 lb 8 oz are read as one weight. Tonnes (metric, short and long) are read too.
- Volume: metric (ml, L) or US customary (tsp, tbsp, fl oz, qt, gal), with the unit following the size — cups and spoons use the page's region (a cup is 250 ml by default). Recipe fractions such as 1/2 cup are read. Cubic inches, feet, yards and metres are read as volume.
- Power: watts and kilowatts or horsepower (W, kW, hp, BTU/h).
- Shoe size: EU, UK or Japan (cm), read only next to a shoe word and shown with the original, such as UK 8 as about EU 41.5. Sizes are shown as ISO Mondopoint (foot length in mm) by default. US sizes are not read.
- Speed: km/h, mph, metres per second or knots (kn only with a speed or wind word).
- Fuel economy: L/100 km, mpg (US or UK, also written out) or km/L.
- Torque: N·m or lb-ft (ft-lb only next to a torque word).
- Cooking: UK gas marks as a temperature and US butter sticks as grams.
- Dates and times: converted to ISO 8601 UTC or International Atomic Time — only when the page text names an explicit source timezone; UnitAnchor never guesses one.

Presets and per-unit control

Choose a preset — Metric, US customary, Canadian, UK / imperial or SI (scientific) — to set every unit at once, or pick each one individually. Changing any single unit switches the preset to Custom automatically, so your choices are never silently overwritten. Large and small numbers can use SI prefixes or scientific notation.

Optional currency conversion

Current exchange rates are off until you turn them on on the Network page. Once on, UnitAnchor fetches public daily rates from the Bank of Canada, Frankfurter or the European Central Bank, sending only your chosen target currency code, and does the conversion locally. Until then, amounts convert at built-in yearly average rates, marked as approximate. Turning the rates off clears the saved rates.

Supported languages

UnitAnchor's interface is available in English (Canada), French (Canada), German, Italian, Japanese, Spanish and Simplified Chinese.