# VPD Chart vs VPD Tool

The clearest difference is price: VPD Chart at Free against VPD Tool's $0.49. VPD Chart also leads on ratings volume (30 vs 1) and update cadence (every 3 weeks vs every 2 months). VPD Tool's advantage is rating (5.0 vs 4.5) and in-app purchases (none vs 2). On ads and device support there is nothing between them.

VPD Chart is free to download; VPD Tool costs $0.49 up front. VPD Chart sells 2 in-app purchases, starting at $3.99 per month. VPD Tool asks for nothing beyond the download.

VPD Tool holds the better App Store score, 5.0 against 4.5. That said, the two scores are not equally well evidenced: VPD Chart has 30 ratings behind it against 1, so its average is the more settled of the two. Written reviews point the same way: 74% of VPD Chart's written reviews are positive against 100% of VPD Tool's.

VPD Chart ships an update every 3 weeks, VPD Tool every 2 months. The most recent releases landed on September 22, 2026 and September 14, 2026 respectively.

## The numbers

| Metric | VPD Chart | VPD Tool |
| --- | --- | --- |
| Price | **Free** | $0.49 |
| Rating | [4.5 (30 ratings)](https://appshunter.io/ios/app/vpd-chart/id6470015847/reviews) | **[5.0 (1 ratings)](https://appshunter.io/ios/app/vpd-tool/id6751213834/reviews)** |
| Number of ratings | **30** | 1 |
| Positive reviews | 73.7% of reviews | **100.0% of reviews** |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | **Every 3 weeks** | Every 2 months |
| Monetization | **Free with in-app purchases** | Paid |
| Size | 49 MB | 2 MB |
| Requires iOS | **15.1** | 18.5 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [INNOVO DEV S.R.L.](https://appshunter.io/developer/1814828527) | [Nicholas Hwang](https://appshunter.io/developer/1802240669) |

## 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 |


### VPD Tool

[App page](https://appshunter.io/ios/app/vpd-tool/id6751213834)

This utility app helps growers understand Vapor Pressure Deficit (VPD) for optimal plant growth. It features an interactive heatmap and stage presets to guide environmental adjustments. Calculations are performed on-device for privacy.

**Highlights:** Interactive VPD heatmap, Stage-specific VPD ranges, Leaf and Air VPD calculation, Home and Lock Screen widgets, On-device calculations, CSV log export

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

**In-app purchases:** none


## Frequently asked questions

### Is VPD Chart free?

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

### Is VPD Tool free?

VPD Tool costs $0.49, with no in-app purchases.

### Which has better reviews, VPD Chart or VPD Tool?

VPD Tool is rated higher. VPD Chart averages 4.5 out of 5 from 30 ratings, while VPD Tool averages 5.0 from 1 ratings.

### Do VPD Chart or VPD Tool have ads?

Neither VPD Chart nor VPD Tool shows ads.

### Which is updated more often, VPD Chart or VPD Tool?

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