# Light Spectrometer Wavelength vs PPFD METER

The clearest difference is ads: Light Spectrometer Wavelength at none against PPFD METER's shown. Light Spectrometer Wavelength also leads on review sentiment (73% vs 53%) and iOS requirement (15.0 vs 18.0). PPFD METER's advantage is rating (4.6 vs 4.2) and update cadence (every 3 weeks vs every 2 months). On price, ratings volume, in-app purchases and monetization model there is nothing between them.

Both are free to download. Light Spectrometer Wavelength sells 4 in-app purchases, starting at $0.99 per month and PPFD METER sells 3 in-app purchases, starting at $1.99 per month. Whichever you choose, the download price is not the number that matters.

PPFD METER holds the better App Store score, 4.6 against 4.2. Both are backed by a comparable volume of ratings — 94 and 125 respectively. Written reviews complicate that: 73% of Light Spectrometer Wavelength's written reviews are positive against 53% of PPFD METER's, so the app with the better star average is not the one people write more warmly about.

Light Spectrometer Wavelength ships an update every 2 months, PPFD METER every 3 weeks. The most recent releases landed on October 9, 2026 and October 10, 2026 respectively.

## The numbers

| Metric | Light Spectrometer Wavelength | PPFD METER |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [4.2 (94 ratings)](https://appshunter.io/ios/app/light-spectrometer-wavelength/id6450930820/reviews) | **[4.6 (125 ratings)](https://appshunter.io/ios/app/ppfd-meter-grow-light-meter/id6479329051/reviews)** |
| Number of ratings | 94 | **125** |
| Positive reviews | **72.7% of reviews** | 52.6% of reviews |
| In-app purchases | Yes | Yes |
| Ads | **No** | Yes |
| Update frequency | Every 2 months | **Every 3 weeks** |
| Monetization | Free with in-app purchases | Free with in-app purchases |
| Size | 43 MB | 46 MB |
| Requires iOS | **15.0** | 18.0 |
| Devices | **iPhone, iPad, iPod** | iPhone, iPad |
| Age rating | 4+ | 4+ |
| Developer | [Contechity AB](https://appshunter.io/developer/1649290454) | [Candas Pamukcu](https://appshunter.io/developer/1735587895) |

## What reviewers say

### Light Spectrometer Wavelength

[App page](https://appshunter.io/ios/app/light-spectrometer-wavelength/id6450930820)

This application analyzes light to determine its dominant wavelength in nanometers, frequency in terahertz, and period length in femtoseconds. It provides real-time measurements and allows users to save their findings with notes. The app is designed for measuring colored light sources.

**Highlights:** Measures dominant wavelength (nm), Measures frequency (THz), Measures period length (fs), Real-time measurement, Save measurements with notes, Optional calibration

**Features:** Vision Pro support

**In-app purchases (4)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Full Access | $0.99 | per month |
| Full access | $0.99 | per month |
| Full access | $4.99 | per year |
| Full access | $6.99 | one-time |


### PPFD METER

[App page](https://appshunter.io/ios/app/ppfd-meter-grow-light-meter/id6479329051)

This app measures light intensity for plants, converting LUX to PPFD and DLI. It offers advanced light mapping, uniformity analysis, and efficiency insights to optimize plant growth. Customize profiles for different environments and growth stages.

**Highlights:** LUX, PPFD, DLI, and PAR measurements, Light mapping and distribution analysis, Uniformity and PPF evaluation, Energy efficiency and consumption tracking, Customizable setting profiles, Bluetooth sensor integration

**In-app purchases (3)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Premium | $1.99 | per month |
| Premium Plus | $2.99 | per month |
| Remove Ads | $29.99 | one-time |


## Frequently asked questions

### Is Light Spectrometer Wavelength free?

Light Spectrometer Wavelength is free to download, with in-app purchases available.

### Is PPFD METER free?

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

### Which has better reviews, Light Spectrometer Wavelength or PPFD METER?

PPFD METER is rated higher. Light Spectrometer Wavelength averages 4.2 out of 5 from 94 ratings, while PPFD METER averages 4.6 from 125 ratings.

### Do Light Spectrometer Wavelength or PPFD METER have ads?

PPFD METER shows ads; Light Spectrometer Wavelength does not.

### Which is updated more often, Light Spectrometer Wavelength or PPFD METER?

Light Spectrometer Wavelength ships an update every 2 months, and PPFD METER every 3 weeks. Most recently, Light Spectrometer Wavelength was updated on October 9, 2026 and PPFD METER on October 10, 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.*