GD&T Calculator

⌀

Calculators

⊕

MMC

Bonus Ready

⊞

Stack Methods

◎

GD&T Symbols

Quick Bonus Tolerance

MMC modifier — instant result

Actual Mating Size

MMC Size

Stated Tolerance

Bonus0.05

Total Tolerance0.10

Quick True Position

Measured X/Y deviation

ΔX (measured)

ΔY (measured)

Tolerance Diameter

Positional Deviation0.100

StatusPASS

What is GD&T?

Geometric Dimensioning and Tolerancing (GD&T) is a symbolic language used on engineering drawings to describe nominal geometry and allowable variation. It communicates design intent clearly between designers, manufacturers, and inspectors per ASME Y14.5-2018 standard. Key concepts: MMC (Maximum Material Condition), LMC (Least Material Condition), Bonus Tolerance, True Position, and Tolerance Stack-Up.

Tolerance Zone Calculator

Compute upper/lower limits from nominal and bilateral/unilateral tolerances

Bilateral

Unilateral

Limit Dims

Nominal Size

+Tolerance

−Tolerance

Upper Limit (UL)25.050

Lower Limit (LL)24.950

Tolerance Band0.100

Midpoint25.000

LLTolerance BandUL

MMC & LMC Calculator

Maximum and Least Material Condition for holes and shafts

Feature Type

Nominal Diameter

Upper Deviation (+)

Lower Deviation (−)

Maximum Material Condition (MMC)20.000

Least Material Condition (LMC)20.050

Tolerance Band0.050

Mid-Tolerance20.025

For a Hole: MMC = smallest hole (least material removed). LMC = largest hole.

Bonus Tolerance Calculator

Applies when MMC (⊕) or LMC (⊖) modifier is used on a feature of size

⊕ Bonus = |AMS − MMC|

Feature Type

Modifier

MMC Size

LMC Size

Actual Mating Size (AMS)

Stated Geometric Tolerance

Bonus Tolerance0.100

Total Allowable Tolerance0.150

Tolerance Zone Diameter⌀ 0.150

Feature at MMC?No

Feature at LMC?No

Stated: 0.050Bonus: 0.100Total: 0.150

Fits & Clearance / Interference Calculator

Shaft & Hole assembly fit analysis

Hole

MMC (Min Dia)

LMC (Max Dia)

Shaft

MMC (Max Dia)

LMC (Min Dia)

Max Clearance0.092

Min Clearance0.013

Fit TypeCLEARANCE FIT

Hole Tolerance0.052

Shaft Tolerance0.027

True Position Calculator

Determine positional deviation and pass/fail status

2D (X/Y)

3D (X/Y/Z)

True Position X (nominal)

True Position Y (nominal)

Measured X

Measured Y

Position Tolerance Diameter (⌀)

ΔX0.030

ΔY0.040

True Position (⌀)0.100

Allowed Tolerance0.100

Deviation Used100.0%

ResultPASS

0Position UsedTolerance Limit

Form Tolerance Calculator

Flatness, Straightness, Circularity, Cylindricity

GD&T Symbol

Tolerance Value

Measured Max Value

Nominal Size (reference)

Symbol⏥ Flatness

Tolerance Zone Width0.020

Measured Error0.015

Remaining Margin0.005

Used (%)75.0%

StatusWITHIN TOLERANCE

0Measured ErrorTol. Limit

Worst Case Tolerance Stack-Up

Linear chain — all tolerances add arithmetically

Nominal Gap / Closure—

Total Tolerance (±)—

Maximum Gap—

Minimum Gap—

Worst case: ΔTotal = Σ|tᵢ| — conservative, used for safety-critical parts.

RSS Tolerance Stack-Up

Root Sum of Squares — statistical approach (±3σ)

Nominal Gap—

RSS Tolerance (±)—

Max Gap—

Min Gap—

WC vs RSS Reduction—

RSS: Δ = √Σtᵢ² — more realistic, ~99.73% of assemblies within limits.

6-Sigma Tolerance Stack-Up

Modified RSS with Cp — accounts for process capability

Default Cp (Process Capability)

Nominal Gap—

6σ Tolerance (±)—

Max Gap—

Min Gap—

DPMO (est.)—

6σ Stack: Δ = (1/Cp) × √Σtᵢ² — Cp=1.5 ≈ 3.4 DPMO.

GD&T Symbol Reference

ASME Y14.5-2018 — click a symbol to see details

Form

Orientation

Location

Runout

Profile & Modifiers

GD&T Calc

Dashboard