ISO Fits vs Bolt Length
Price, ratings, monetisation and update history for both apps, side by side — with what reviewers say about each.
ISO Fits
Calculate ISO fits and tolerances for shafts and bores. Supports metric and inch units, displays detailed fit definitions, and includes visual charts and educational videos.
- ISO fits calculation
- Tolerance class display
- Metric/inch unit switching
- Tolerance charts
- Updated YouTube videos
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It includes the following features: - Fits calculation: Upon entering the nominal diameter (of either bore or shaft), users select their tolerance classes for bore and shaft. The app then provides the complete ISO fits definition with all relevant values. - Tolerances: Shows the tolerances for the most commonly used ISO tolerance classes. - switch between metric and inch version. - Charts: Shows the most common ISO tolerances classes in a diagram. - Videos: Features the automatically updated latest TSS youtube videos. The results of this application are based on DIN ISO 286 Nominal dimension: 1-3150mm following tolerances included: Shaft: a9, a10, a11, a12, a13, b8, b9, b10, b11, b12, b13, c8, c9, c10, c11, c12, cd5, cd6, cd7, cd8, cd9, cd10, d5, d6, d7, d8, d9, d10, d11, d12, d13, e5, e6, e7, e8, e9, e10, ef3, ef4, ef5, ef6, ef7, ef8, ef9, ef10, f3, f4, f5, f6, f7, f8, f9, f10, fg3, fg4, fg5, fg6, fg7, fg8, fg9, fg10, g3, g4, g5, g6, g7, g8, g9, g10, h1, h2, h3, h4, h5, h6, h7, h8, h9, h10, h11, h12, h13, h14, h15, h16, h17, h18, js1, js2, js3, js4, js5, js6, js7, js8, js9, js10, js11, js12, js13, js14, js15, js16, js17, js18, j5, j6, j7, j8, k3, k4, k5, k6, k7, k8, k9, k10, k11, k12, k13, m3, m4, m5, m6, m7, m8, m9, n3, n4, n5, n6, n7, n8, n9, p3, p4, p5, p6, p7, p8, p9, p10, r3, r4, r5, r6, r7, r8, r9, r10, s3, s4, s5, s6, s7, s8, s9, s10, t5, t6, t7, t8, u5, u6, u7, u8, u9, v5, v6, v7, v8, x5, x6, x7, x8, x9, x10, y6, y7, y8, y9, y10, z6, z7, z8, z9, z10, z11, za6, za7, za8, za9, za10, za11, zb7, zb8, zb9, zb10, zb11, zc7, zc8, zc9, zc10, zc11 Bore: A9, A10, A11, A12, A13, B8, B9, B10, B11, B12, B13, C8, C9, C10, C11, C12, C13, CD6, CD7, CD8, CD9, CD10, D6, D7, D8, D9, D10, D11, D12, D13, E5, E6, E7, E8, E9, E10, EF3, EF4, EF5, EF6, EF7, EF8, EF9, EF10, F3, F4, F5, F6, F7, F8, F9, F10, FG3, FG4, FG5, FG6, FG7, FG8, FG9, FG10, G3, G4, G5, G6, G7, G8, G9, G10, H1, H2, H3, H4, H5, H6, H7, H8, H9, H10, H11, H12, H13, H14, H15, H16, H17, H18, JS1, JS2, JS3, JS4, JS5, JS6, JS7, JS8, JS9, JS10, JS11, JS12, JS13, JS14, JS15, JS16, JS17, JS18, J6, J7, J8, J9, K3, K4, K5, K6, K7, K8, K9, K10, M3, M4, M5, M6, M7, M8, M9, M10, N3, N4, N5, N6, N7, N8, N9, N10, N11, P3, P4, P5, P6, P7, P8, P9, P10, R3, R4, R5, R6, R7, R8, R9, R10, S3, S4, S5, S6, S7, S8, S9, S10, T5, T6, T7, T8, U5, U6, U7, U8, U9, U10, V5, V6, V7, V8, X5, X6, X7, X8, X9, X10, Y6, Y7, Y8, Y9, Y10, Z6, Z7, Z8, Z9, Z10, Z11, ZA6, ZA7, ZA8, ZA9, ZA10, ZA11, ZB7, ZB8, ZB9, ZB10, ZB11, ZC7, ZC8, ZC9, ZC10, ZC11
Bolt Length
This application helps calculate the length of metric coarse screws based on Japanese Industrial Standards. It is designed for mechanical design purposes and should be used at the user's own risk.
- Metric coarse screw length calculation
- Conforms to Japanese Industrial Standards (JIS)
- Designed for mechanical design
- User risk disclaimer
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This app is an application for calculating the length of the screw. ※:This app does not guarantee the effectiveness of the combination. ※:Use this application at your own risk. Conforms to the Japanese Industrial Standards (JIS). Screws are all metric coarse screw. For mechanical design. Sorry, Only in Japan.Because using the JIS.
Screenshots
Verdict
The clearest difference is review sentiment: ISO Fits at 95% against Bolt Length's 33%. ISO Fits also leads on rating (4.2 vs 3.0) and ads (none vs shown). On price, in-app purchases, monetization model 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
Both are free to download. ISO Fits sells 1 one-off in-app purchase and Bolt Length sells 1 one-off in-app purchase. Whichever you choose, the download price is not the number that matters.
ISO Fits holds the better App Store score, 4.2 against 3.0. Both are backed by a comparable volume of ratings — 6 and 2 respectively. Written reviews point the same way: 95% of ISO Fits's written reviews are positive against 33% of Bolt Length's.
ISO Fits ships an update every 5 months, Bolt Length every 20 months. The most recent releases landed on October 23, 2026 and November 1, 2026 respectively.
| Parameter | ISO Fits | Bolt Length |
|---|---|---|
| Price | Free | Free |
| Rating | 4.2 (6 ratings) — better | 3.0 (2 ratings) |
| Positive reviews | 94.6% of reviews — better | 33.3% of reviews |
| Number of ratings | 6 — better | 2 |
| Update frequency | Every 5 months — better | Every 20 months |
| Ads | No — better | Yes |
| In-app purchases | Yes | Yes |
| Monetization | Free with in-app purchases | Free with in-app purchases |
| Devices | iPhone, iPad, iPod | iPhone, iPad, iPod |
| Requires iOS | 15.6 | 14.0 — better |
| Further details — not scored | ||
| Size | 66 MB | 6 MB |
| Age rating | 4+ | 4+ |
| Developer | Trelleborg Sealing Solutions | mitsunori oishi |
Customer experience
ISO Fits
Bolt Length
In-app purchases
ISO Fits
- Full Version with complete ISO286 Standard$1.99
Bolt Length
- Hide Ads$1.99
Questions
Is ISO Fits free?
Is Bolt Length free?
Which has better reviews, ISO Fits or Bolt Length?
Do ISO Fits or Bolt Length have ads?
Which is updated more often, ISO Fits or Bolt Length?
Other comparisons
