III vs STEPPASS（ステップパス）
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
III
Calculate material properties for III-V compound semiconductors like AlGaInAsP. It determines compositions, lattice constant, strain, bandgap, and effective masses for InP or GaAs substrates.
- III-V compound semiconductor calculations
- Material property determination
- Composition calculation (x, y, z)
- Lattice constant and strain analysis
- Bandgap and effective mass calculation
- Supports InP and GaAs substrates
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Application to calculate the compositions and material properties of a III-V compound semiconductor. Either InP or GaAs is assumed for the substrate. Some of the compositions and material parameters of the AlGaInAsP compound semiconductor are specified to determine the remain unknown parameters. The following properties are shown as a result: compositions (x, y, z), lattice constant, strain, bandgap, relative energy positions of the conduction and valence bands, and effective masses of the electron and holes.
STEPPASS（ステップパス）
This app delivers important messages and notifications directly to your smartphone. It ensures you never miss crucial updates from your learning center through push notifications.
- Receive messages on smartphone
- Push notification alerts
- Prevent missed messages
- Exclusive for STEP students
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「STEPPASS（ステップパス）」アプリは、学習塾ステップに通学している方のみご利用いただけます。 「STEPPASS（ステップパス）」アプリをインストールすることで、これまでメールで届いていたメッセージがスマートフォン（アプリ）に届きます。 また、「プッシュ機能」でメッセージが届いたことを通知するので見逃し防止に役立ちます。
Screenshots
Verdict
The clearest difference is review sentiment: III at 100% against STEPPASS（ステップパス）'s 25%. STEPPASS（ステップパス）'s advantage is price (Free vs $2.99). On update cadence, ads, in-app purchases and device support there is nothing between them.
Scored on Price · Rating · Positive reviews · Number of ratings · Update frequency · Ads · In-app purchases · Monetization · Best chart rank · Devices · Requires iOS
STEPPASS（ステップパス） is free to download; III costs $2.99 up front. Neither carries in-app purchases, so what you see is what you pay.
III ships an update every 17 months, STEPPASS（ステップパス） every 15 months. The most recent releases landed on August 24, 2026 and September 21, 2026 respectively.
| Parameter | III | STEPPASS（ステップパス） |
|---|---|---|
| Price | $2.99 | Free — better |
| Rating | 4.0 (1 ratings) — better | — |
| Positive reviews | 100.0% of reviews — better | 25.0% of reviews |
| Number of ratings | 1 — better | — |
| Update frequency | Every 17 months | Every 15 months — better |
| Ads | No | No |
| In-app purchases | No | No |
| Monetization | Paid | Free — better |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 11.0 — better | 12.0 |
| Further details — not scored | ||
| Size | 10 MB | 12 MB |
| Age rating | 4+ | 4+ |
| Developer | Takuya Ishikawa | STEP CO., LTD. (Kanagawa) |
Customer experience
III
STEPPASS（ステップパス）
In-app purchases
III
No in-app purchases
STEPPASS（ステップパス）
No in-app purchases
