# Smart Obra vs Concrete & Stair Calculator

The clearest difference is in-app purchases: Smart Obra at none against Concrete & Stair Calculator's 3. On price, update cadence, ads and device support there is nothing between them.

Both are free to download. Concrete & Stair Calculator sells 3 in-app purchases, starting at $2.99 per month. Smart Obra asks for nothing beyond the download.

Smart Obra ships an update every 2 months, Concrete & Stair Calculator every 5 weeks. Both last shipped on October 28, 2026.

## The numbers

| Metric | Smart Obra | Concrete & Stair Calculator |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | — | 100.0% of reviews |
| In-app purchases | **No** | Yes |
| Ads | No | No |
| Update frequency | Every 2 months | **Every 5 weeks** |
| Monetization | — | Freemium |
| Size | 39 MB | 42 MB |
| Requires iOS | 15.1 | **15.0** |
| Devices | **iPhone, iPad, iPod** | iPhone, iPod |
| Age rating | 17+ | 4+ |
| Developer | [Vision360 Innovations](https://appshunter.io/developer/1880772929) | [Devolim](https://appshunter.io/developer/1823631894) |

## What reviewers say

### Smart Obra

[App page](https://appshunter.io/ios/app/smart-obra/id6759808564)

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

**In-app purchases:** none


### Concrete & Stair Calculator

[App page](https://appshunter.io/ios/app/concrete-and-stair-calculator/id6766280669)

This app provides over 70 construction trade calculations, displaying results in 3D with dimensions. It adapts to local units and rules, offering an AI assistant for job site questions. Organize calculations by project for easy access.

**Highlights:** 70+ trade calculations, 3D result visualizations, AI job site assistant (Pro), Offline calculations, Project organization, Unit and rule adaptation

**Features:** macOS Compatibility, Family Sharing

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Blok Pro Monthly | $2.99 | per month |
| Blok Pro Yearly | $17.99 | per year |
| Blok Pro Lifetime | $29.99 | one-time |


## Frequently asked questions

### Is Smart Obra free?

Smart Obra is free to download, with no in-app purchases.

### Is Concrete & Stair Calculator free?

Concrete & Stair Calculator is free to download, with in-app purchases available.

### Do Smart Obra or Concrete & Stair Calculator have ads?

Neither Smart Obra nor Concrete & Stair Calculator shows ads.

### Which is updated more often, Smart Obra or Concrete & Stair Calculator?

Smart Obra ships an update every 2 months, and Concrete & Stair Calculator every 5 weeks. Most recently, Smart Obra was updated on October 28, 2026 and Concrete & Stair Calculator on October 28, 2026.

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