Comparison

CalculatorRed vs calculator DUO

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

Head to head
About

CalculatorRed

Features
Read full description

Introducing CalculatorRed – Your Go-To Calculator for iPad & iPhone: Unleash the power of simplicity with CalculatorRed, the ultimate calculator app designed specifically for your iPad and iPhone. Whether you're tackling homework, managing household finances, or calculating on-the-go, CalculatorRed provides a seamless and intuitive computing experience. Why Choose CalculatorRed? - Optimized for iPad: Enjoy calculations on a grand scale with our large, easy-to-read display that makes complex computations less daunting. Perfect for both professional and educational settings, our interface is designed to maximize productivity on your iPad’s expansive screen. - iPhone Friendly: Don't have your iPad at hand? No problem! CalculatorRed works flawlessly on your iPhone as well, maintaining clarity and ease of use on a smaller scale. It’s always there when you need it, right in your pocket. - Simple & Efficient: This no-frills calculator gets back to basics, offering you all the essential functions without any complicated extras. It’s user-friendly for all ages and skill levels. - Completely Free & Ad-Free: We believe in straightforward computing without distractions. That's why CalculatorRed is completely free to use with no ads. No interruptions, just uninterrupted calculating. Whether you’re a student, teacher, professional, or someone who just needs a quick and easy tool for everyday calculations, CalculatorRed is designed to meet your needs. Download CalculatorRed today and experience the simplest, most effective way to manage all your numerical tasks on your favorite devices!

About

calculator DUO

This utility app offers a modern calculator with a visual history feature, eliminating the need to memorize previous calculations. It also includes a comprehensive unit converter and a tip calculator that bases tips on pre-tax amounts.

Highlights
  • Visual history calculator (RESULT SHELF™)
  • Unit converter
  • Tip calculator (pre-tax)
  • Distraction-free design
  • Precise and efficient
Features
Read full description

A scientific calculator with history, memory and a keypad made for one hand. Save useful answers and tap to use them again on iPhone and iPad. WITHIN THUMB REACH Move and resize the left- or right-hand keypad to suit your grip. KEEP THE ANSWERS YOU NEED Save useful results on a visual shelf. Tap to reuse them, recall your last answer, or search your calculation history and mark favorites. CORRECT INPUT WITH CONFIDENCE Swipe to delete a digit or function. The deleted content stays visible until your next input; tap the return button to undo the deletion. FROM EVERYDAY TO SCIENTIFIC Use arithmetic, percentages, powers, roots, logarithms and trigonometric functions. Long-press a result for a large display, with adjustable text, color, font and size. MAKE IT YOURS Five themes, optional digit grouping and an interface in 50 languages. No account is required. Expressions, saved results and calculation history are stored on your device. DATES AND TIME, TOO Find the time between two dates, add or subtract days and hours, and calculate across time zones. The free app may show banner ads. Remove Ads is an optional one-time purchase, with purchase restoration through the same Apple Account.

Screenshots

CalculatorRed3 screens
calculator DUO4 screens

Verdict

The call

The clearest difference is in-app purchases: CalculatorRed at none against calculator DUO's 1. CalculatorRed also leads on ads (none vs shown). calculator DUO's advantage is update cadence (every 10 days vs every 4 weeks). On price, device support and iOS requirement 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

Both are free to download. calculator DUO sells 1 one-off in-app purchase. CalculatorRed asks for nothing beyond the download.

UpkeepUpdate frequency

CalculatorRed ships an update every 4 weeks, calculator DUO every 10 days. The most recent releases landed on October 27, 2026 and October 9, 2026 respectively.

Scorecard3 real differences · 7 level
CalculatorRed versus calculator DUO: the parameters behind the verdict, then further details
ParameterCalculatorRedcalculator DUO
PriceFreeFree
Rating—5.0 (3 ratings) — better
Positive reviews—100.0% of reviews
Number of ratings—3 — better
Update frequencyEvery 4 weeksEvery 10 days — better
AdsNo — betterYes
In-app purchasesNo — betterYes
Monetization—Free with in-app purchases
DevicesiPhone, iPadiPhone, iPad
Requires iOS17.016.5 — better
Further details — not scored
Size1 MB11 MB
Age rating4+4+
DeveloperKodwerk Software Ltd.Wenbin lei

In-app purchases

None

CalculatorRed

No in-app purchases

1 purchases

calculator DUO

One-time1
  • Remove Ads$7.99

Questions

Is CalculatorRed free?
CalculatorRed is free to download, with no in-app purchases.
Is calculator DUO free?
calculator DUO is free to download, with in-app purchases available.
Do CalculatorRed or calculator DUO have ads?
calculator DUO shows ads; CalculatorRed does not.
Which is updated more often, CalculatorRed or calculator DUO?
CalculatorRed ships an update every 4 weeks, and calculator DUO every 10 days. Most recently, CalculatorRed was updated on October 27, 2026 and calculator DUO on October 9, 2026.

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