Comparison

Units vs ChangeUnits2

Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.

Head to head
About

Units

Easily convert between hundreds of units across 43 categories, including currency with daily updated rates. Customize your workflow by hiding or reordering units and categories.

Highlights
  • Hundreds of units across 43 categories
  • Daily updated currency exchange rates
  • Hide unused units
  • Reorder units and categories
  • Universal app support (iPhone, iPod touch, iPad)
Features
Read full description

Units is the fast, friendly unit converter. Type a number into any unit and instantly see it in every other one, all on a single screen. There's no picking what to convert from and to, no digging through menus, and no ads. With more than 800 units across 43 categories, Units covers everyday conversions like length, weight, volume and temperature, and the ones you need less often, from torque and fuel consumption to data rates, shoe sizes and musical notes. SEE EVERYTHING AT ONCE • Enter a value in any unit and every other unit in the category updates as you type • A keypad made for numbers, so the decimal point is always right where you need it CURRENCY • Convert between more than 160 currencies • Exchange rates updated every day MAKE IT YOURS • Hide the units you never use, so the ones you need are always in view • Reorder units and categories so your favorites come first • Switch on a two-column layout to see even more at a glance • Leave a tip to unlock a collection of alternative app icons MADE FOR YOUR DEVICES • Designed for iPhone and iPad, with your categories and conversion side by side on larger screens • Makes full use of iPhone Duo, whether it's open or closed • Handoff picks up a conversion where you left off on another device • Supports Dark Mode and Dynamic Type Units has been converting since 2008, and is lovingly made in Scotland.

About

ChangeUnits2

This powerful utility app offers lightning-fast and accurate unit conversions for a wide range of needs. It includes advanced math functions, currency exchange, time zone tracking, and even chemical equation balancing. Designed for professionals and everyday users alike, it works offline and remembers your last calculations.

Highlights
  • Extreme speed and accuracy
  • Offline functionality
  • Currency exchange converter
  • Global time zone tracking
  • Advanced math functions
  • Chemical equation balancing
  • Last 33 calculations remembered
Features
Read full description

Designed by an Engineer from the Semiconductor Industry, ChangeUnits2 is Built for Extreme Speed and Versatility. ChangeUnits2 is Very Fast. ChangeUnits2 is Very Accurate. ChangeUnits2 Fits inside your Pocket and Doesn't Require a Signal. ChangeUnits2 even Knows what Time it will be HERE (in your Current Location) at 7am in Tokyo. ChangeUnits2 is Built for EVERYONE. It has a Button for virtually ANY Unit and is Very Easy to Use. Tap on the Woman Welder on the Right to Launch the Quick Unit Selection Screen. Toggle the "Longform List" / "Engineering List" button to Switch Between 1) a List of Unit Buttons in Shortform Engineering style, or 2) in Longform style for a more Wordy Description. note: this ALSO toggles between Scientific Notation & Standard Decimal Form. Quickly change between Thermal Units of BTUs / Therms / Kwh / kCals / and even Gallons of Gasoline Need even more Significant Figures? Just add Zero's to the end of the number you entered, press "Convert Units" and ChangeUnits2 will do the rest. Use the built in Currency Converter travelCash, travelCash2, travelCash3 and travelCash4 to Easily VISUALIZE ANY Monetary Exchange Rate. Whether the Exchange Rate is in [Dollars : Donuts] or [Donuts : Dollars]....ChangeUnits2 handles it like a Pro! Effortlessly Calculate the Number of Pints of Beer held in a 1/2 Barrel Keg for your Big Football Party. Converting Between Standard and Metric has never been so Easy!! Easily keep track of the Time in Major Cities while you are ANYWHERE in the World!! No signal needed. Use the Globe Buttons to arrange International Meetings.....based on your Preferred Time....or even Theirs. Schedule a meeting at 7am Tokyo time, or 7am Los Angeles time. ConvertUnits2 will help you keep track of time like a Pro. Perform advanced math functions right in the App. It's so easy and convenient! Even exponents, Ln, Log, Prime Numbers and Square Roots. Balance Chemical Equations from ANYWHERE! Now you can bring your Periodic Table of the Elements with You! Thank you, Uncle Sam! Calculate the Minimum Fall Time / Maximum Energies / Maximum Speeds of a Fall from nearly ANY Height. Now you're the real life McGuber! The "Last Values" button Remembers your Last 33 Calculations using "Convert Units" Now you can show Data you compiled right on your iPhone without re-entering the Information. It's so Easy ChangeUnits2 will Change your Life for the Better It's a Science & Engineering Professional's Dream!

Screenshots

Units4 screens
ChangeUnits24 screens

Verdict

The call

The clearest difference is price: Units at Free against ChangeUnits2's $0.99. Units also leads on ratings volume (51 vs 1). ChangeUnits2's advantage is rating (5.0 vs 4.1) and in-app purchases (none vs 3). On update cadence and device support there is nothing between them.

Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS

CostPrice · In-app purchases · Ads · Monetization

Units is free to download; ChangeUnits2 costs $0.99 up front. Units sells 3 one-off in-app purchases. ChangeUnits2 asks for nothing beyond the download.

ReceptionRating · Positive reviews · Number of ratings

ChangeUnits2 holds the better App Store score, 5.0 against 4.1. That said, the two scores are not equally well evidenced: Units has 51 ratings behind it against 1, so its average is the more settled of the two.

UpkeepUpdate frequency

Units ships an update monthly, ChangeUnits2 every 4 weeks. The most recent releases landed on November 6, 2026 and November 7, 2026 respectively.

Scorecard7 real differences · 3 level
Units versus ChangeUnits2: the parameters behind the verdict, then further details
ParameterUnitsChangeUnits2
PriceFree — better$0.99
Rating4.1 (51 ratings)5.0 (1 ratings) — better
Positive reviews60.1% of reviews—
Number of ratings51 — better1
Update frequencyMonthlyEvery 4 weeks — better
AdsYesNo — better
In-app purchasesYesNo — better
MonetizationFree with in-app purchases — betterPaid
DevicesiPhone, iPadiPhone, iPad, iPod — better
Requires iOS17.015.6 — better
Further details — not scored
Size86 MB17 MB
Age rating4+4+
DeveloperHomegrown Software LtdJack McCormack

Customer experience

Units

All ratings49 ratings
Positive79.6%
Neutral4.1%
Negative16.3%
Written reviews581 reviews
Positive60.1%
Neutral12.0%
Negative27.9%

ChangeUnits2

All ratings1 ratings
Positive100.0%
Neutral0.0%
Negative0.0%

Bugs and requests

Units

Reported bugs

4 issues
  • Crashes when clearing input fields
  • Numerical keypad covers conversion results
  • Incompatibility issues with newer iOS versions
  • Ruler measurements not accurate on all devices

Requested features

5 requests
  • Add nautical units (miles, knots)
  • Improve currency conversion accuracy and updates
  • Allow customization of visible unit categories
  • Add more clothing/shoe size conversions
  • Improve user interface and search functionality

ChangeUnits2

Not enough reviews yet to summarise bugs or requests.

In-app purchases

3 purchases

Units

One-time3
  • Small Tip$0.99
  • Medium Tip$2.99
  • Large Tip$4.99
None

ChangeUnits2

No in-app purchases

Questions

Is Units free?
Units is free to download, with in-app purchases available.
Is ChangeUnits2 free?
ChangeUnits2 costs $0.99, with no in-app purchases.
Which has better reviews, Units or ChangeUnits2?
ChangeUnits2 is rated higher. Units averages 4.1 out of 5 from 51 ratings, while ChangeUnits2 averages 5.0 from 1 ratings.
Do Units or ChangeUnits2 have ads?
Units shows ads; ChangeUnits2 does not.
Which is updated more often, Units or ChangeUnits2?
Units ships an update monthly, and ChangeUnits2 every 4 weeks. Most recently, Units was updated on November 6, 2026 and ChangeUnits2 on November 7, 2026.

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