# Plumbing Formulator vs iManifold

The clearest difference is rating: Plumbing Formulator at 4.6 against iManifold's 3.1. Plumbing Formulator also leads on monetization model (free vs free with in-app purchases). iManifold's advantage is review sentiment (50% vs 9%) and update cadence (every 3 weeks vs every 2 months). On price, ads, in-app purchases and device support there is nothing between them.

Both are free to download. Plumbing Formulator sells 4 one-off in-app purchases and iManifold sells 10 one-off in-app purchases. Whichever you choose, the download price is not the number that matters.

Plumbing Formulator holds the better App Store score, 4.6 against 3.1. That said, the two scores are not equally well evidenced: iManifold has 38 ratings behind it against 7, so its average is the more settled of the two. Written reviews complicate that: 9% of Plumbing Formulator's written reviews are positive against 50% of iManifold's, so the app with the better star average is not the one people write more warmly about.

Plumbing Formulator ships an update every 2 months, iManifold every 3 weeks. Both last shipped on October 23, 2026.

## The numbers

| Metric | Plumbing Formulator | iManifold |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.6 (7 ratings)](https://appshunter.io/ios/app/plumbing-formulator/id303497783/reviews)** | [3.1 (38 ratings)](https://appshunter.io/ios/app/imanifold/id784602842/reviews) |
| Number of ratings | 7 | **38** |
| Positive reviews | 9.1% of reviews | **50.0% of reviews** |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 2 months | **Every 3 weeks** |
| Monetization | **Free** | Free with in-app purchases |
| Size | 123 MB | 29 MB |
| Requires iOS | 18.6 | **12.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 4+ | 4+ |
| Developer | [Historycentral.com](https://appshunter.io/developer/1744330560) | [North Park Innovations Group, Inc.](https://appshunter.io/developer/595381427) |

## 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 |


### iManifold

[App page](https://appshunter.io/ios/app/imanifold/id784602842)

This app calculates HVAC/R system performance and aids in troubleshooting. It offers a wide selection of refrigerants and equipment profiling for various common systems.

**Highlights:** Calculates HVAC/R system performance, Troubleshoots system problems, User input and live system data, Over 40 selectable refrigerants, Equipment profiling options, Customizable for common HVAC/R systems

**Features:** macOS Compatibility

**In-app purchases (10)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Charge & Airflow Report | $0.99 | one-time |
| Mechanical Inspection | $0.99 | one-time |
| Equipment Replacement Report | $0.99 | one-time |
| CSV Export | $0.99 | one-time |
| Annualized Savings Report | $0.99 | one-time |
| Gas Furnace Report | $0.99 | one-time |
| iManifold Report Pro - 1 Circuit | $1.99 | one-time |
| iManifold Report Pro - 2 Circuit | $2.99 | one-time |
| iManifold Report Pro - 3 Circuit | $3.99 | one-time |
| iManifold Report Pro - 4 Circuit | $4.99 | one-time |


## Frequently asked questions

### Is Plumbing Formulator free?

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

### Is iManifold free?

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

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

Plumbing Formulator is rated higher. Plumbing Formulator averages 4.6 out of 5 from 7 ratings, while iManifold averages 3.1 from 38 ratings.

### Do Plumbing Formulator or iManifold have ads?

Neither Plumbing Formulator nor iManifold shows ads.

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

Plumbing Formulator ships an update every 2 months, and iManifold every 3 weeks. Most recently, Plumbing Formulator was updated on October 23, 2026 and iManifold on October 23, 2026.

---

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