ISO Fits vs GD&T
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
GD&T
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Learn, interpret and inspect GD&T according to ISO 1101. This app describes a large range of definitions of geometric dimensioning and tolerancing and supports engineers and employees as a multimedia reference book. As part of operative education, this app shows relationships and makes it easier to understand the right handling of form and position tolerances in practice. This app explains the most important definitions of GD&T and its interpretation by examples (straightness, roundness, flatness, cylindricity, profile of a line, parallelism, squareness, angularity, position, concentricity, symmetry, circular runout, …) -25 animations -Basic information -Form tolerance -Profile tolerance -Position tolerance -Orientation tolerance -Runout tolerance
Screenshots
Verdict
The clearest difference is in-app purchases: GD&T at none against ISO Fits's 1. ISO Fits's advantage is update cadence (every 5 months vs every 11 months). On price, ads, device support 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. ISO Fits sells 1 one-off in-app purchase. GD&T asks for nothing beyond the download.
ISO Fits ships an update every 5 months, GD&T every 11 months. The most recent releases landed on November 6, 2026 and October 26, 2026 respectively.
| Parameter | ISO Fits | GD&T |
|---|---|---|
| Price | Free | Free |
| Rating | 4.2 (6 ratings) — better | — |
| Positive reviews | 94.6% of reviews | — |
| Number of ratings | 6 — better | — |
| Update frequency | Every 5 months — better | Every 11 months |
| Ads | No | No |
| In-app purchases | Yes | No — better |
| Monetization | Free with in-app purchases | — |
| Devices | iPhone, iPad, iPod — better | iPhone, iPod |
| Requires iOS | 15.6 | 15.0 — better |
| Further details — not scored | ||
| Size | 66 MB | 56 MB |
| Age rating | 4+ | 4+ |
| Developer | Trelleborg Sealing Solutions | Carl Zeiss AG |
In-app purchases
ISO Fits
- Full Version with complete ISO286 Standard$1.99
GD&T
No in-app purchases







