# GWP vs Physics Questions

The clearest difference is in-app purchases: GWP at none against Physics Questions's 9. GWP also leads on ads (none vs shown). Physics Questions's advantage is update cadence (every 4 days vs every 38 months). On price, device support and iOS requirement there is nothing between them.

Both are free to download. Physics Questions sells 9 one-off in-app purchases. GWP asks for nothing beyond the download.

GWP ships an update every 38 months, Physics Questions every 4 days. The most recent releases landed on October 23, 2026 and October 6, 2026 respectively.

## The numbers

| Metric | GWP | Physics Questions |
| --- | --- | --- |
| Price | Free | Free |
| Positive reviews | 100.0% of reviews | — |
| In-app purchases | **No** | Yes |
| Ads | **No** | Yes |
| Update frequency | Every 38 months | **Every 4 days** |
| Monetization | Free | — |
| Size | 28 MB | 20 MB |
| Requires iOS | **11.0** | 12.0 |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Age rating | 17+ | 4+ |
| Developer | [UNEP](https://appshunter.io/developer/1106793919) | [Michael Todd](https://appshunter.io/developer/1211079532) |

## What reviewers say

### GWP

[App page](https://appshunter.io/ios/app/gwp-odp-calculator/id1288285449)

This tool helps convert between metric tonnes, ODP tonnes, and CO2-equivalent tonnes for substances controlled by the Montreal Protocol. It features two modes: 'Actual Values' and 'Kigali Amendment', and supports English, French, and Spanish.

**Highlights:** Converts metric tonnes, ODP tonnes, and CO2-equivalent tonnes, Includes Kigali Amendment mode, Supports 'Actual Values' and 'Kigali Amendment' modes, Displays substance ODP, GWP, and description, Calculates for single component substances and refrigerant mixtures, Available in English, French, and Spanish

**Features:** macOS Compatibility

**In-app purchases:** none


### Physics Questions

[App page](https://appshunter.io/ios/app/physics-questions/id1616961005)

**Features:** macOS Compatibility, Family Sharing

**In-app purchases (9)**

| Purchase | Price | Billing |
| --- | --- | --- |
| Electricity Questions | $1.99 | one-time |
| Electronics Questions | $1.99 | one-time |
| Electromagnetism Questions | $1.99 | one-time |
| Force & Energy Questions | $1.99 | one-time |
| Motion Questions | $1.99 | one-time |
| Optics Questions | $1.99 | one-time |
| Radioactivity & Thermodynamics | $1.99 | one-time |
| Special Relativity Questions | $1.99 | one-time |
| Waves & Particles Questions | $1.99 | one-time |


## Frequently asked questions

### Is GWP free?

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

### Is Physics Questions free?

Physics Questions is free to download, with in-app purchases available.

### Do GWP or Physics Questions have ads?

Physics Questions shows ads; GWP does not.

### Which is updated more often, GWP or Physics Questions?

GWP ships an update every 38 months, and Physics Questions every 4 days. Most recently, GWP was updated on October 23, 2026 and Physics Questions on October 6, 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.*