# Perfect Structure vs calc318

The clearest difference is monetization model: Perfect Structure at free with in-app purchases against calc318's subscription. Perfect Structure also leads on update cadence (every 2 days vs every 3 months) and device support (3 vs 1). calc318's advantage is ads (none vs shown). On price, rating, ratings volume and in-app purchases there is nothing between them.

Both are free to download. Perfect Structure sells 1 one-off in-app purchase and calc318 sells 2 in-app purchases, starting at $2.99 per month. Whichever you choose, the download price is not the number that matters.

On the App Store both sit at effectively the same score — 5.0 for Perfect Structure against 5.0 for calc318. Both are backed by a comparable volume of ratings — 1 and 1 respectively.

Perfect Structure ships an update every 2 days, calc318 every 3 months. The most recent releases landed on October 11, 2026 and October 1, 2026 respectively.

## The numbers

| Metric | Perfect Structure | calc318 |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [5.0 (1 ratings)](https://appshunter.io/ios/app/perfect-structure/id1581860758/reviews) | [5.0 (1 ratings)](https://appshunter.io/ios/app/calc318/id6763030413/reviews) |
| Number of ratings | 1 | 1 |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | Yes | Yes |
| Ads | Yes | **No** |
| Update frequency | **Every 2 days** | Every 3 months |
| Monetization | **Free with in-app purchases** | Subscription |
| Size | 32 MB | 19 MB |
| Requires iOS | **15.0** | 26.0 |
| Devices | **iPhone, iPad, iPod** | iPhone |
| Age rating | 4+ | 4+ |
| Developer | [Gokhan Behcet Sahin](https://appshunter.io/developer/1409805750) | [ARTIFICIAL INTELLIGENCE OPTIMIZATION AND SOFTWARE AIOS LLC](https://appshunter.io/developer/1835191566) |

## What reviewers say

### Perfect Structure

[App page](https://appshunter.io/ios/app/perfect-structure/id1581860758)

Design and optimize reinforced concrete columns and beams with support for multiple international design codes and languages. Generate reports in PDF, CSV, and DXF formats, and share them with colleagues. Offers a user-friendly interface for quick and flexible structural analysis.

**Highlights:** Reinforced concrete column and beam design, Support for 5 international design codes, Multilingual support (8 languages), Output in PDF, CSV, and DXF formats, Modern and user-friendly interface, Design checks and optimal reinforcement calculation

**Features:** macOS Compatibility

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Perfect Structure Pro | $8.99 | one-time |


### calc318

[App page](https://appshunter.io/ios/app/calc318/id6763030413)

Instantly solve 175 ACI 318-19 equations with live computation and interactive charts. Understand equation behavior with sensitivity graphs and clear variable descriptions. Designed for engineers needing quick, accurate calculations and insights.

**Highlights:** 175 ACI 318-19 equations solved instantly, Live computation with unit awareness, Interactive sensitivity graphs, Professionally formatted equations, Complete variable descriptions, Smart search functionality, Recents tab for quick access

**Features:** macOS Compatibility, Family Sharing, Vision Pro support

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| calc318 Pro Monthly | $2.99 | per month |
| calc318 Pro Yearly | $12.99 | per year |


## Frequently asked questions

### Is Perfect Structure free?

Perfect Structure is free to download, with in-app purchases available.

### Is calc318 free?

calc318 is free to download, with in-app purchases available.

### Which has better reviews, Perfect Structure or calc318?

Perfect Structure and calc318 are both rated 5.0 out of 5 on the App Store, from 1 and 1 ratings respectively.

### Do Perfect Structure or calc318 have ads?

Perfect Structure shows ads; calc318 does not.

### Which is updated more often, Perfect Structure or calc318?

Perfect Structure ships an update every 2 days, and calc318 every 3 months. Most recently, Perfect Structure was updated on October 11, 2026 and calc318 on October 1, 2026.

---

*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*