Custom Formulas vs CalcFlex
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
Custom Formulas
This utility app allows users to create and manage complex calculations with multiple inputs and outputs. Formulas can be linked, grouped into categories, and customized for display precision. Share your custom calculations easily via email.
- Multiple input/output formula support
- Linked formulas via variable names
- Formula categorization
- Customizable variable display order
- Adjustable output decimal precision
- Email formula sharing
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This app is easy to use, but unlike simpler apps, multiple entered values can be fed into multiple formulas and multiple output values can be displayed. The output of one formula in a group can be fed into the next by using the same variable name. Related formulas can be grouped into categories to make them easy to find. e.g. Maths formulas, Surveying formulas, Loan interest formulas etc. The order of variables displayed to the user can be changed, as can the number of decimal digits of precision shown in the output fields. You can easily share formulas with other users of the app by emailing them. Three example formulas are pre-installed with the app. In order of increasing complexity they are: slope percentage, compound interest, and point scale factor.
CalcFlex
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Discover CalcFlex: Flexible, Free and Ad-Free Calculator App! Unlock the full potential of your calculations with CalcFlex, the flexible calculator app designed to cater to all your needs. Whether you're dealing with complex equations, unit conversions, financial calculations, or scientific formulas, CalcFlex has got you covered. Key Features: Multiple Calculators in Parallel: Seamlessly switch between different calculators for efficiency. Built-in Tools: Access unit converters, finance calculators, math and physics equations all in one app. Custom Equations: Create, save, and reuse your own equations with specific variables tailored to your needs. User-Friendly Design: Start with the familiar calculator layout, free to customize based on preference. Completely Free: No ads, no hidden fees, just pure calculating power. Download CalcFlex now and experience the freedom of a truly flexible and comprehensive calculator app!
Screenshots
Verdict
The clearest difference is price: CalcFlex at Free against Custom Formulas's $3.99. Custom Formulas's advantage is in-app purchases (none vs 6) and chart position (#186 vs unranked). On update cadence and ads 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
CalcFlex is free to download; Custom Formulas costs $3.99 up front. CalcFlex sells 3 one-off in-app purchases. Custom Formulas asks for nothing beyond the download.
Custom Formulas ships an update every 5 days, CalcFlex every 9 days. The most recent releases landed on September 18, 2026 and September 19, 2026 respectively.
| Parameter | Custom Formulas | CalcFlex |
|---|---|---|
| Price | $3.99 | Free — better |
| Rating | 5.0 (1 ratings) — better | — |
| Positive reviews | 100.0% of reviews | — |
| Number of ratings | 1 — better | — |
| Update frequency | Every 5 days — better | Every 9 days |
| Ads | No | No |
| In-app purchases | No — better | Yes |
| Monetization | Paid | — |
| Best chart rank | #186 — better | — |
| Devices | iPhone, iPad, iPod — better | iPhone |
| Requires iOS | 15.4 — better | 17.0 |
| Further details — not scored | ||
| Size | 1 MB | 2 MB |
| Age rating | 4+ | 4+ |
| Developer | Anthony Dunk | Daniel Chiu Loong Ng |
In-app purchases
Custom Formulas
No in-app purchases
CalcFlex
- +3 New Variables2 variants$1.99
- +20 New Equation Slots2 variants$1.99
- +1 New Calculator2 variants$3.99









