Amazon / Travel / ALL UNIT CONVERTER
REVIEW
All Unit Converter is a calculator with a thousand modes.
A free Fire utility that covers everything from kilograms to nautical miles and stays out of your way — provided you can tolerate the ad that loads between conversions.
BY THE APP COMRADE DESK · MAY 10, 2026 · 3 MIN READ
All Unit Converter
FOURARC TECHNOLOGY
OUR SCORE
6.5
AMAZON
★ 5.0
PRICE
Free
Unit converters are the unsexy backbone of every utility category. Nobody downloads one on purpose — you download one because the recipe is in grams, the oven is in Fahrenheit, the suitcase scale is in pounds, and the airline limit is in kilograms. The app you install is whichever one shows up first in the store search, and the one you keep is whichever one didn’t immediately frustrate you.
All Unit Converter is somewhere in the middle of that test. It is free, the unit coverage is broad enough to handle anything short of a chemistry homework set, and the currency module pulls live rates. It is also wrapped in enough advertising to make every conversion feel like a small toll.
For a free Fire tablet utility from a developer with no other notable releases, that’s roughly the deal you should expect.
It is the kind of utility you install once, forget, and only remember the next time you have to convert square feet to acres at midnight.
FEATURES
All Unit Converter packs the standard utility spread into a single Fire tablet app: length, mass, area, volume, temperature, speed, time, pressure, energy, power, force, angle, data storage, and fuel economy. Each category opens to a two-field layout — pick the source unit, type a number, pick the target unit, read the result. Conversions update as you type.
Currency is included and pulls live exchange rates over the network. Rates refresh on launch when the tablet is online; if the device is offline, the converter falls back to the last cached set, which is honest behavior for a free utility. The app filed itself under Amazon's Travel category rather than Utilities, presumably on the strength of the currency module — a categorisation choice that says more about Amazon's taxonomy than about the app.
The interface is plain Android-style spinners and number pads. No widgets, no Fire TV companion, no Alexa hooks. Just a converter.
MISSION ACCOMPLISHED
The unit coverage is genuinely broad — niche scales like astronomical units, light-years, parsecs, troy ounces, and cooking-specific volumes like teaspoons and US cups all show up alongside the obvious metric and imperial entries. For a free download from a developer most people have never heard of, the breadth is a real point in its favor.
Performance is also fine. Cold launches in under two seconds on a current-generation Fire HD, and conversions are instant once the unit pickers are open. Nothing about the app feels slow or buggy.
ROOM TO IMPROVE
The ad density is the obvious complaint. A banner sits at the bottom of every screen, and a full-screen interstitial fires roughly every third conversion or category switch. For a tool people open to do one quick calculation, the interruption is more annoying than the same density would be inside a game. There is no paid tier to remove ads, so the only relief is airplane mode.
The design is also dated. The layout has not been refreshed in several years; spinners look like stock Android from two major OS versions ago, and the result text is small enough on a 10-inch Fire HD that older readers will squint. Currency rates also update once per launch — fine for casual use, not for anyone watching FX moves.
CONCLUSION
All Unit Converter is the right shape for the right reader: someone who needs to convert something occasionally on a Fire tablet, will not pay for a converter, and can stomach a full-screen ad once in a while. For frequent use, the built-in calculator on most modern Fires plus a web search will be less frustrating. For everyone else, it is free, it works, and it stays installed.