Comparison

Calculator² vs Sigma Notepad Calculator

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

Head to head
About

Calculator²

This app offers a suite of specialized calculators, including scientific, financial, programmer, and basic functions. It also features a currency converter and a comprehensive unit converter for various needs.

Highlights
  • Scientific calculator with advanced functions
  • Financial calculator for loan and tax calculations
  • Programmer calculator for number base conversions
  • Currency converter with real-time rates
  • Unit converter for over 200 units
  • Basic calculator for everyday use
Features
Read full description

The smart calculator for iOS. Scientific Calculator An advanced calculator with a comprehensive set of mathematical functions including trigonometric, hyperbolic, logarithmic, exponential, factorial, combination and permutation. Over 125 mathematical and physical constants are accessible in an easy-to-navigate list. Implicit multiplication and operator precedence are supported for faster input, while the unique memory mode also provides a facility for statistical functions. Financial Calculator* A calculator with a variety of functions for performing financial calculations, such as determining the monthly payments on a loan or the price of an item after tax has been applied. Individual rates can be set for markup, discount, tax and interest. Perfect for students and professionals who wish to verify the results of time value of money calculations. Programmer Calculator A powerful tool for conversions between decimal, hexadecimal, octal and binary number bases, with a unique view for entering ASCII keys. Bitwise operations including AND, OR, XOR and NOT are available, in addition to functions not usually found in a programmer calculator, such as square and factorial. Basic Calculator A simple, easy-to-use calculator for quick, everyday calculations. Currency Converter* A currency calculator providing accurate conversions between 150+ World currencies. The exchange rates are easily updated to real-time values from the Open Exchange Rates API, while favourite currency conversions can be saved for easy comparisons. Unit Converter A comprehensive unit converter with over 200 units across 26 categories, including temperature, fuel consumption, viscosity, radiation and more. * The Financial Calculator and Currency Converter are unlocked by an in-app purchase

About

Sigma Notepad Calculator

Features
Read full description

$610 left this month, before rent went out, and you never typed a sum. Sigma is a notepad that does the math while you write: every line shows its answer, and the total stays in view above the keyboard. Know what’s left before you spend it. Write "pay = $2400", then your bills, "rent: $1200" and "food: $380", and "left = pay - total" shows $820. Rent goes up? Change one number and everything below follows. Split the bill at the table. Dinner for four, tip included, comes to $51.75 each before anyone reaches for a card. Then send the whole sheet to the group chat as one image, every line and the total included. Know what the trip costs before you book. Flights in dollars, the hotel in euros, the train in Swiss francs: one total, all in, in your own currency. Rates stay live and keep working offline. Never add up the same list twice. Tick what’s paid and the total shows what’s still to pay. Give each part of a list a heading and each part gets its own total. And all the everyday math around it. How many days until an invoice is due. Whether a 220 cm sofa fits an 8 ft wall. What you really saved at the sale. What a week of freelance work comes to. Percentages, units, dates and currencies, written the way you’d say them, with square roots, hex and trigonometry when you need them. Every line answers as you type. No formulas, no grid, and one rule to learn: a colon counts, an equals sign doesn’t. Free: three sheets and the full calculator. No ads, no time limit. Sigma Pro keeps every month: unlimited sheets, iCloud sync, export to PDF, Markdown and plain text, and five more themes. Billed yearly, monthly, or once for life. New subscribers get a 7-day free trial on the yearly plan. Your sheets stay on your iPhone, and iCloud sync uses your own private iCloud database, never our servers. Works in English and French. Terms of Use (EULA): https://www.apple.com/legal/internet-services/itunes/dev/stdeula/ Privacy Policy: https://getsigma.app/privacy

Screenshots

Calculator²4 screens
Sigma Notepad Calculator4 screens

Verdict

The call

The clearest difference is update cadence: Sigma Notepad Calculator at fortnightly against Calculator²'s every 3 months. Calculator²'s advantage is iOS requirement (9.0 vs 17.0). On price, ads, in-app purchases 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

Both are free to download. Calculator² sells 3 one-off in-app purchases and Sigma Notepad Calculator sells 3 in-app purchases, starting at $1.99 per month. Whichever you choose, the download price is not the number that matters.

UpkeepUpdate frequency

Calculator² ships an update every 3 months, Sigma Notepad Calculator fortnightly. The most recent releases landed on October 16, 2026 and October 25, 2026 respectively.

Scorecard2 real differences · 6 level
Calculator² versus Sigma Notepad Calculator: the parameters behind the verdict, then further details
ParameterCalculator²Sigma Notepad Calculator
PriceFreeFree
Positive reviews100.0% of reviews—
Update frequencyEvery 3 monthsFortnightly — better
AdsNoNo
In-app purchasesYesYes
MonetizationFree with in-app purchases—
DevicesiPhone, iPod — betteriPhone
Requires iOS9.0 — better17.0
Further details — not scored
Size78 MB16 MB
Age rating4+4+
DeveloperRichard WaltersSoules Studio Ltd

In-app purchases

3 purchases

Calculator²

One-time3
  • Financial Calculator$0.99
  • Currency Converter$0.99
  • Calculator² Premium$1.99
3 purchases

Sigma Notepad Calculator

Subscriptions2
  • Monthly$1.991 Month
  • Annual7 Days trial$14.991 Year
One-time1
  • Lifetime$29.99

Questions

Is Calculator² free?
Calculator² is free to download, with in-app purchases available.
Is Sigma Notepad Calculator free?
Sigma Notepad Calculator is free to download, with in-app purchases available.
Do Calculator² or Sigma Notepad Calculator have ads?
Neither Calculator² nor Sigma Notepad Calculator shows ads.
Which is updated more often, Calculator² or Sigma Notepad Calculator?
Calculator² ships an update every 3 months, and Sigma Notepad Calculator fortnightly. Most recently, Calculator² was updated on October 16, 2026 and Sigma Notepad Calculator on October 25, 2026.

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