# VPD Chart vs DrainMaster Plus

VPD Chart and DrainMaster Plus are too close to call on the numbers: across 6 compared parameters — price, update cadence, ads and in-app purchases among them — neither pulls far enough ahead to decide it. What separates them is feature set and interface, not measurable difference.

Both are free to download. VPD Chart sells 2 in-app purchases, starting at $3.99 per month and DrainMaster Plus sells 1 in-app purchase, starting at $3.99 per month. Whichever you choose, the download price is not the number that matters.

VPD Chart ships an update every 3 weeks, DrainMaster Plus every 2 weeks. The most recent releases landed on September 22, 2026 and September 23, 2026 respectively.

## The numbers

| Metric | VPD Chart | DrainMaster Plus |
| --- | --- | --- |
| Price | Free | Free |
| Rating | **[4.5 (30 ratings)](https://appshunter.io/ios/app/vpd-chart/id6470015847/reviews)** | — |
| Number of ratings | **30** | — |
| Positive reviews | 73.7% of reviews | — |
| In-app purchases | Yes | Yes |
| Ads | No | No |
| Update frequency | Every 3 weeks | **Every 2 weeks** |
| Monetization | Free with in-app purchases | — |
| Size | 49 MB | 67 MB |
| Requires iOS | 15.1 | 15.1 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 4+ | 12+ |
| Developer | [INNOVO DEV S.R.L.](https://appshunter.io/developer/1814828527) | [kobosil.me Development](https://appshunter.io/developer/951054288) |

## What reviewers say

### VPD Chart

[App page](https://appshunter.io/ios/app/vpd-chart/id6470015847)

This app calculates Vapor Pressure Deficit (VPD) using air temperature, relative humidity, and canopy temperature. It offers real-time charting, sensor integration, and educational tools to understand plant growth environments. Organize data by zones and visualize dew point areas.

**Highlights:** VPD calculation, Interactive VPD chart, Sensor integration, Zone organization, Dew point visualization, Grow Timeline

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

**In-app purchases (2)**

| Purchase | Price | Billing |
| --- | --- | --- |
| VPD Chart Plus (monthly) | $3.99 | per month |
| VPD Chart Plus (annual) | $29.99 | per year |


### DrainMaster Plus

[App page](https://appshunter.io/ios/app/drainmaster-plus/id6752567739)

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

**In-app purchases (1)**

| Purchase | Price | Billing |
| --- | --- | --- |
| DrainMaster Cloud Monthly | $3.99 | per month |


## Frequently asked questions

### Is VPD Chart free?

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

### Is DrainMaster Plus free?

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

### Do VPD Chart or DrainMaster Plus have ads?

Neither VPD Chart nor DrainMaster Plus shows ads.

### Which is updated more often, VPD Chart or DrainMaster Plus?

VPD Chart ships an update every 3 weeks, and DrainMaster Plus every 2 weeks. Most recently, VPD Chart was updated on September 22, 2026 and DrainMaster Plus on September 23, 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.*