# Plumbing Formulator vs YearViewer

The clearest difference is review sentiment: YearViewer at 67% against Plumbing Formulator's 9%. YearViewer also leads on in-app purchases (none vs 4) and rating (5.0 vs 4.6). Plumbing Formulator's advantage is update cadence (every 2 months vs every 5 months) and ratings volume (7 vs 2). On price, ads, monetization model and device support there is nothing between them.

Both are free to download. Plumbing Formulator sells 4 one-off in-app purchases. YearViewer asks for nothing beyond the download.

YearViewer holds the better App Store score, 5.0 against 4.6. Both are backed by a comparable volume of ratings — 7 and 2 respectively. Written reviews point the same way: 9% of Plumbing Formulator's written reviews are positive against 67% of YearViewer's.

Plumbing Formulator ships an update every 2 months, YearViewer every 5 months. The most recent releases landed on October 30, 2026 and October 14, 2026 respectively.

## The numbers

| Metric | Plumbing Formulator | YearViewer |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.6 (7 ratings)](https://appshunter.io/ios/app/plumbing-formulator/id303497783/reviews) | **[5.0 (2 ratings)](https://appshunter.io/ios/app/yearviewer/id304045410/reviews)** |
| Number of ratings | **7** | 2 |
| Positive reviews | 9.1% of reviews | **66.7% of reviews** |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | **Every 2 months** | Every 5 months |
| Monetization | Free | Free |
| Size | 123 MB | 1 MB |
| Requires iOS | 18.6 | **8.0** |
| Devices | iPhone, iPad | iPhone, iPod |
| Age rating | 4+ | 4+ |
| Developer | [Historycentral.com](https://appshunter.io/developer/1744330560) | [Gerard Putter](https://appshunter.io/developer/284862847) |

## What reviewers say

### Plumbing Formulator

[App page](https://appshunter.io/ios/app/plumbing-formulator/id303497783)

This professional calculator app provides over 200 formulas, calculators, and reference materials for plumbers, HVAC technicians, and mechanical contractors. It covers a wide range of calculations for water flow, piping, drainage, water heaters, pumps, and more, all in one pocket-sized tool.

**Highlights:** Over 200 formulas and calculators, Water flow and supply calculations, Pipe and piping calculations, Drainage and venting calculations, Water heater and pump calculations, Reference charts and code books, Pipe cut list optimizer

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

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Pro Version | $1.99 | one-time |
| Pro Purchase | $3.99 | one-time |
| Starter | $5.99 | one-time |
| Growth | $9.99 | one-time |


### YearViewer

[App page](https://appshunter.io/ios/app/yearviewer/id304045410)

View a calendar overview for any year, past or future. Customize your view with optional week numbers, adjustable start days, and different week layouts. Pinch to zoom and use device settings for language.

**Highlights:** Yearly calendar overview, Select any past or future year, Optional week numbers (ISO 8601), Customizable first day of the week, Pinch-to-zoom functionality, Device language integration

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is Plumbing Formulator free?

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

### Is YearViewer free?

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

### Which has better reviews, Plumbing Formulator or YearViewer?

YearViewer is rated higher. Plumbing Formulator averages 4.6 out of 5 from 7 ratings, while YearViewer averages 5.0 from 2 ratings.

### Do Plumbing Formulator or YearViewer have ads?

Neither Plumbing Formulator nor YearViewer shows ads.

### Which is updated more often, Plumbing Formulator or YearViewer?

Plumbing Formulator ships an update every 2 months, and YearViewer every 5 months. Most recently, Plumbing Formulator was updated on October 30, 2026 and YearViewer on October 14, 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.*