# VPD Chart vs HydroponicsCalc

The clearest difference is price: VPD Chart at Free against HydroponicsCalc's $1.99. VPD Chart also leads on ratings volume (30 vs 1) and iOS requirement (15.1 vs 26.5). HydroponicsCalc'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; HydroponicsCalc costs $1.99 up front. VPD Chart sells 2 in-app purchases, starting at $3.99 per month. HydroponicsCalc asks for nothing beyond the download.

HydroponicsCalc 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.

## The numbers

| Metric | VPD Chart | HydroponicsCalc |
| --- | --- | --- |
| Price | **Free** | $1.99 |
| Rating | [4.5 (30 ratings)](https://appshunter.io/ios/app/vpd-chart/id6470015847/reviews) | **[5.0 (1 ratings)](https://appshunter.io/ios/app/hydroponicscalc/id6775172331/reviews)** |
| Number of ratings | **30** | 1 |
| Positive reviews | 73.7% of reviews | — |
| In-app purchases | Yes | **No** |
| Ads | No | No |
| Update frequency | Every 3 weeks | — |
| Monetization | **Free with in-app purchases** | Paid |
| Size | 49 MB | 1 MB |
| Requires iOS | **15.1** | 26.5 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [INNOVO DEV S.R.L.](https://appshunter.io/developer/1814828527) | [Douglas Stieber](https://appshunter.io/developer/6771586128) |

## 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 |


### HydroponicsCalc

[App page](https://appshunter.io/ios/app/hydroponicscalc/id6775172331)

Manage your hydroponic garden with this comprehensive tool. Track reservoir levels, mix nutrients precisely, calculate pH and VPD, and document your grow with a journal and harvest log. Supports both US and metric units.

**Highlights:** Reservoir management dashboard, Concentrate and EC mixing calculators, pH and VPD calculators, Grow journal with photo timeline, Harvest log and ROI dashboard, Light schedule tracker, US & Metric unit support

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is VPD Chart free?

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

### Is HydroponicsCalc free?

HydroponicsCalc costs $1.99, with no in-app purchases.

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

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

### Do VPD Chart or HydroponicsCalc have ads?

Neither VPD Chart nor HydroponicsCalc shows ads.

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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.*