📐 GD&T · ASME Y14.5-2018

GD&T Calculators

Free geometric dimensioning and tolerancing tools: True Position, Flatness, Circularity, Runout, Bonus Tolerance, Stack-Up & more. Per ASME Y14.5-2018 and ISO 1101.

18 Calculators

5 Categories

Free No Login

Y14.5 Standard

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ℹ️ All calculators follow ASME Y14.5-2018 and ISO 1101 standards. Results are for reference. Verify critical tolerances with your quality team.

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Location & Position

6 tools

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Location

True Position

Positional deviation from nominal. 2D (X/Y) and 3D (X/Y/Z) modes. Pass/Fail with gauge.

TP = 2 × √(ΔX² + ΔY²)

Maximum and Least Material Condition for holes and shafts. Upper/lower limits with mid-tolerance.

MMC (hole) = Nominal − Lower Dev

Compute bonus tolerance when MMC/LMC modifier is applied. Total allowable tolerance zone.

Median point deviation from datum axis. Deprecated in Y14.5-2018, for legacy drawing support.

Con = 2 × √(ΔX² + ΔY²)

Shaft and hole assembly fit: clearance, interference, or transition fit with max/min values.

MaxClear = LMC_hole − LMC_shaft

Upper/lower limits from nominal: bilateral, unilateral, or limit dimension inputs.

UL = Nom + T⁺ | LL = Nom − T⁻

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Form Tolerances

5 tools

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Form

Flatness

Controls how flat a surface is. Two parallel planes define the zone. No datum required.

Error ≤ Tolerance → PASS

Roundness check per cross-section. Measured error vs zone between two coaxial circles.

Error ≤ Tolerance → PASS

Line element or axis straightness. Applied to surface lines or feature axes. % margin shown.

Error ≤ Tolerance → PASS

Full cylinder form: roundness + straightness + taper combined. No datum required.

Error ≤ Tolerance → PASS

Bilateral and unilateral surface profile tolerance. Inner/outer boundary and zone width.

Zone = t | Boundaries = Nom ± t/2

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Runout

2 tools

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Runout

Circular Runout

FIM at each cross-section independently. Enter multiple readings, auto-takes max.

Max FIM ≤ Tolerance → PASS

All surface points simultaneously relative to datum axis. Combines circularity and coaxiality.

Max FIM (full surface) ≤ Tolerance

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Tolerance Stack-Up

3 tools

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Stack-Up

Worst Case

All tolerances add arithmetically. Conservative, used for safety-critical assemblies.

Root Sum of Squares, statistical (±3σ). ~99.73% of assemblies within limits.

Modified RSS with Cp. Cp=1.5 gives ~3.4 DPMO. Process capability estimate included.

Δ = (1/Cp) × √Σtᵢ²

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Reference

2 tools

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Reference

GD&T Symbols

All 14+ GD&T symbols: Form, Orientation, Location, Runout, Profile and Modifiers.

ASME Y14.5-2018 | ISO 1101

Quick Bonus Tolerance and True Position on one screen. Instant overview with key stats.

Quick calc, no setup needed

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Why I Built This

GD&T shop floor pe implement karna aur drawings ko correctly interpret karna. Yeh dono ek saath seekhna hota hai. Ek side pe standard hai (ASME Y14.5), doosri side pe real parts hain jo CMM ya gauge se measure hote hain.

Yeh calculators usi gap ko bridge karte hain: True Position se lekar Bonus Tolerance, Runout, Profile, aur Tolerance Stack-Up tak. Saare results ASME Y14.5-2018 ke formulas pe based hain. No login, no ads, free to use.

Part of TaskJunction, free mechanical engineering calculators for Indian students, engineers, and shop floor teams.

Vaibhav Dhokpande · Mechanical Engineer & Developer · TaskJunction