Comparison

FunctionCalc vs ThetaCalc

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

Head to head
About

FunctionCalc

This all-in-one utility app helps veterans calculate VA disability benefits, track important dates, and perform everyday calculations. It includes a tip splitter, unit converter, and a powerful calculator with saved formulas.

Highlights
  • VA disability benefit calculator
  • Date countdown and elapsed time tracker
  • Tip calculator and bill splitting
  • Unit and currency converter
  • Time math and custom formulas
  • Full calculation history
Features
Read full description

VA disability calculator, date tracker, tip splitter, unit converter, and powerful everyday calculator in one app. Built for veterans and useful for everyone, this all-in-one toolkit helps you calculate VA disability benefits, track important dates, do time math, split bills, convert units and currency, and save formulas you use again and again. Whether you are planning a new claim, checking a countdown, or solving everyday math faster, everything is in one clean, easy-to-use app. VA Disability Calculator Enter your service-connected ratings and instantly see your combined disability rating using the official VA combined rating method, rounded the way the VA does it. Estimate monthly compensation based on your rating, dependents, marital status, and spouse Aid & Attendance eligibility. Create what-if scenarios by adding, removing, or changing ratings to see how a new claim, rating increase, appeal, or dependent update could affect your monthly pay before you file or submit changes. Date Calculator Track the time to or from any date that matters. Save sobriety milestones, anniversaries, retirement countdowns, due dates, memorial dates, birthdays, and more. See a live breakdown in years, months, days, hours, minutes, and seconds. Tap any unit to view the full span as a single total, including total days or total hours. Calculator Use a full-featured calculator with a clean interface, live results, and full history. See your complete expression as you type and get answers fast. Tip Calculator Calculate tips and split the bill in seconds. Choose your tip, select the number of people, and instantly see accurate per-person totals. Time Math Work with time the way you think. Enter values like 1:45, use them in calculations, and convert between time format and decimals with one tap. Function Calculator Access thousands of conversions and formulas in one place. Convert length, mass, volume, temperature, speed, area, data storage, and more, including live currency exchange rates. Browse built-in formulas or create your own custom formulas and save them for quick access. Why you'll love it: • VA combined rating calculator with estimated monthly compensation • What-if VA disability scenarios for ratings and dependent changes • Date countdowns and elapsed time tracking • Tip calculator and bill splitting • Time-format math • Unit conversions and live currency rates • Custom formulas and quick access favorites • Full calculation history • Clean dark interface • No ads. No subscriptions.

About

ThetaCalc

This utility app provides a Reverse Polish Notation (RPN) calculator. Users can extend its functionality by programming custom functions and equations using JavaScript.

Highlights
  • Reverse Polish Notation (RPN) calculator
  • User-programmable functions
  • JavaScript equation support
  • Extensible functionality
Features
Read full description

ThetaCalc is a RPN (Reverse Polish Notation) calculator which can be extended by functions and equations programmed by the user in JavaScript.

Screenshots

FunctionCalc4 screens
ThetaCalc4 screens

Verdict

The call

The clearest difference is price: ThetaCalc at Free against FunctionCalc's $0.99. ThetaCalc also leads on iOS requirement (17.6 vs 26.2). FunctionCalc's advantage is rating (5.0 vs 4.3) and update cadence (every 8 days vs every 3 months). On review sentiment, 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

ThetaCalc is free to download; FunctionCalc costs $0.99 up front. Neither carries in-app purchases, so what you see is what you pay.

ReceptionRating · Positive reviews · Number of ratings

FunctionCalc holds the better App Store score, 5.0 against 4.3. Both are backed by a comparable volume of ratings — 13 and 4 respectively. Written reviews split almost evenly too, at 100% and 100% positive.

UpkeepUpdate frequency

FunctionCalc ships an update every 8 days, ThetaCalc every 3 months. The most recent releases landed on June 5, 2026 and June 1, 2026 respectively.

Scorecard6 real differences · 4 level
FunctionCalc versus ThetaCalc: the parameters behind the verdict, then further details
ParameterFunctionCalcThetaCalc
Price$0.99Free — better
Rating5.0 (13 ratings) — better4.3 (4 ratings)
Positive reviews100.0% of reviews100.0% of reviews
Number of ratings13 — better4
Update frequencyEvery 8 days — betterEvery 3 months
AdsNoNo
In-app purchasesNoNo
MonetizationPaidFree — better
DevicesiPhone, iPadiPhone, iPad
Requires iOS26.217.6 — better
Further details — not scored
Size2 MB1 MB
Age rating4+4+
DeveloperLawler Innovations, Inc.Felix Stehli

Customer experience

FunctionCalc

All ratings13 ratings
Positive100.0%
Neutral0.0%
Negative0.0%
Written reviews2 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

ThetaCalc

All ratings4 ratings
Positive75.0%
Neutral25.0%
Negative0.0%
Written reviews3 reviews
Positive100.0%
Neutral0.0%
Negative0.0%

In-app purchases

None

FunctionCalc

No in-app purchases

None

ThetaCalc

No in-app purchases

Questions

Is FunctionCalc free?
FunctionCalc costs $0.99, with no in-app purchases.
Is ThetaCalc free?
ThetaCalc is free to download, with no in-app purchases.
Which has better reviews, FunctionCalc or ThetaCalc?
FunctionCalc is rated higher. FunctionCalc averages 5.0 out of 5 from 13 ratings, while ThetaCalc averages 4.3 from 4 ratings.
Do FunctionCalc or ThetaCalc have ads?
Neither FunctionCalc nor ThetaCalc shows ads.
Which is updated more often, FunctionCalc or ThetaCalc?
FunctionCalc ships an update every 8 days, and ThetaCalc every 3 months. Most recently, FunctionCalc was updated on June 5, 2026 and ThetaCalc on June 1, 2026.

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