# Span Calc vs PRO

The clearest difference is review sentiment: Span Calc at 30% against PRO's 4%. Span Calc also leads on update cadence (every 10 days vs monthly) and iOS requirement (14.2 vs 16.0). On price, ads, in-app purchases and monetization model there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Span Calc ships an update every 10 days, PRO monthly. The most recent releases landed on October 12, 2026 and October 13, 2026 respectively.

## The numbers

| Metric | Span Calc | PRO |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[2.9 (15 ratings)](https://appshunter.io/ios/app/span-calc/id380481343/reviews)** | — |
| Number of ratings | **15** | — |
| Positive reviews | **29.6% of reviews** | 4.1% of reviews |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 10 days** | Monthly |
| Monetization | Free | Free |
| Size | 168 MB | 5 MB |
| Requires iOS | **14.2** | 16.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 17+ | 4+ |
| Developer | [American Wood Council](https://appshunter.io/developer/380481346) | [Professional Laboratories](https://appshunter.io/developer/1251063237) |

## What reviewers say

### Span Calc

[App page](https://appshunter.io/ios/app/span-calc/id380481343)

Calculate maximum horizontal spans for wood joists and rafters using various lumber species and grades. Compares multiple options for common loading conditions based on NDS® standards.

**Highlights:** Calculates joist and rafter spans, Supports all softwood and hardwood lumber, Uses 2021 NDS® for Wood Construction, Compares multiple species and grades, Handles common loading conditions

**Features:** macOS Compatibility

**In-app purchases:** none


### PRO

[App page](https://appshunter.io/ios/app/pro-lab-test-kits/id1451845323)

This app provides access to a comprehensive range of home safety test kits. These kits accurately measure dangerous pollutants and contaminants in your home or office. All analyses are conducted by accredited laboratories using approved methods.

**Highlights:** Home safety test kits, Pollutant measurement, Contaminant detection, Laboratory analysis, Non-toxic kits

**In-app purchases:** none

**What reviewers like**

- 👍 Simple registration process
- 📧 Email notification for test results

**What reviewers complain about**

- 🚫 Doesn't work for Canadian users
- 🐛 Registration issues - 'all fields required' error
- 💤 App is not updated or maintained
- 🤔 Unclear purpose and functionality of the app

**Reported bugs**

- Registration process doesn't work
- App crashes on certain devices
- Incompatible with current OS versions

**Requested features**

- Ability to save and view historical test results
- Option to pay for tests through the app
- Support for Canadian addresses and postal codes


## Frequently asked questions

### Is Span Calc free?

Span Calc is free to download, with no in-app purchases.

### Is PRO free?

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

### Do Span Calc or PRO have ads?

Neither Span Calc nor PRO shows ads.

### Which is updated more often, Span Calc or PRO?

Span Calc ships an update every 10 days, and PRO monthly. Most recently, Span Calc was updated on October 12, 2026 and PRO on October 13, 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.*