F Numbers vs SUN
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
F Numbers
Quickly find filler metal groupings for welding procedures and performance qualifications. Access classifications with descriptions of intended use, based on ASME and AWS standards.
- Filler metal grouping lookup
- Welding procedure qualification
- Performance qualification data
- Classification descriptions
- ASME Section IX data
- AWS standards data
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F Numbers: Quick lookup of filler metal groupings for welding procedure and performance qualification. Lookup includes classifications with respective descriptions of intended use. Data is provided by C-spec. F-numbers and A-numbers assignments are based on ASME Section IX Table QW-432 and QW-442, ASME Section II Part C, AWS B2.1 Table B1 and B2, and AWS A5.1 through AWS A5.36.
SUN
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The SUN-TEC Hardness Converter is a tool for converting data from one hardness scale to another scale(s) and measuring the hardness of Metallic materials for your applications. Features and Benefits: - Convert between Rockwell, Vickers, Knoop, Brinell, and Leeb hardness scales. - Minimum Thickness and Cylindrical corrections for Rockwell scales. - Diagonal Length(s) conversion to Hardness and Hardness to Diagonal Length(s) for Vickers, Knoop, and Brinell scales. Available Scales: - HRA - HRB - HRC - HRD - HRF - HR15N - HR30N - HR45N - HR15T - HR30T - HR45T - VICKERS - KNOOP - BRINELL - LEEB (HLD) Note: All information within this application tool is for reference only.
Screenshots
Verdict
The clearest difference is device support: F Numbers at 3 against SUN's —. On price, update cadence, in-app purchases and iOS requirement 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
Both are free to download. Neither carries in-app purchases, so what you see is what you pay.
F Numbers ships an update every 13 months, SUN every 14 months. The most recent releases landed on September 15, 2026 and October 11, 2026 respectively.
| Parameter | F Numbers | SUN |
|---|---|---|
| Price | Free | Free |
| Rating | 5.0 (3 ratings) — better | — |
| Number of ratings | 3 — better | — |
| Update frequency | Every 13 months — better | Every 14 months |
| Ads | No | — |
| In-app purchases | No | No |
| Monetization | Free | — |
| Devices | iPhone, iPad, iPod — better | — |
| Requires iOS | 13.0 — better | 13.4 |
| Further details — not scored | ||
| Size | 15 MB | 24 MB |
| Age rating | 4+ | 17+ |
| Developer | ASMEIX CORPORATION | SUN-TEC CORPORATION |
In-app purchases
F Numbers
No in-app purchases
SUN
No in-app purchases









