# VPD Tool vs Markdown

The clearest difference is price: Markdown at Free against VPD Tool's $0.49. Markdown also leads on update cadence (every 8 days vs every 2 months). VPD Tool's advantage is iOS requirement (18.5 vs 26.0). On ads, in-app purchases and device support there is nothing between them.

Markdown is free to download; VPD Tool costs $0.49 up front. Neither carries in-app purchases, so what you see is what you pay.

VPD Tool ships an update every 2 months, Markdown every 8 days. The most recent releases landed on October 30, 2026 and October 25, 2026 respectively.

## The numbers

| Metric | VPD Tool | Markdown |
| --- | --- | --- |
| Price | $0.49 | **Free** |
| Rating | **[5.0 (1 ratings)](https://appshunter.io/ios/app/vpd-tool/id6751213834/reviews)** | — |
| Number of ratings | **1** | — |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | Every 2 months | **Every 8 days** |
| Monetization | Paid | — |
| Size | 2 MB | 10 MB |
| Requires iOS | **18.5** | 26.0 |
| Devices | iPhone, iPad | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Nicholas Hwang](https://appshunter.io/developer/1802240669) | [晟阳 俞](https://appshunter.io/developer/1550483701) |

## What reviewers say

### 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


### Markdown

[App page](https://appshunter.io/ios/app/markdown-img/id6759620992)

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is VPD Tool free?

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

### Is Markdown free?

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

### Do VPD Tool or Markdown have ads?

Neither VPD Tool nor Markdown shows ads.

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

VPD Tool ships an update every 2 months, and Markdown every 8 days. Most recently, VPD Tool was updated on October 30, 2026 and Markdown on October 25, 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.*