Offline • No account • No tracking Made for CNC setup & inspection

Center faster. Calculate fits & tolerances. Estimate stock weight.

CNC Workpiece Calculator is a practical iPhone/iPad toolbox for machinists: probe-based centering across multiple shapes, ISO-style shaft/hole fit checks, general tolerance references, and quick weight estimation for common materials.

View on the App Store See the workflow Contact support

Illustration of CNC workpiece centering and measurement

What it helps you do

Reduce manual math during setup and inspection. Keep your workflow moving with on-device calculations you can trust while standing at the machine.

Probe-based centering

Enter measured X/Y points (with probe diameter compensation) and calculate the center/geometry for circle, rectangle, ellipse, straight slot, and double-circle patterns.

Shaft–hole fits

Quickly check nominal size + tolerance grades (e.g., H7/h6) and see fit outcomes while selecting common hole/shaft types.

Weight estimation

Estimate weight for common shapes (plate, tube, bar, ring…) with material presets, quantity, and metric/imperial units.

General tolerances

Reference size and geometric tolerances (straightness/flatness, perpendicularity, circular runout, etc.) with clear results for shop use.

Built for iPhone & iPad

Touch-friendly inputs and tab-based tools so you can switch between centering, fits, weight, and tolerances without losing context.

Offline by design

No account, no ads, no tracking SDKs. Calculations run on-device so you can work even in restricted network environments.

Quick tutorial

Four common workflows — centering, fits, weight, and tolerances.

Screenshot: Centering tab — add assets/cnc-screenshot-centering.png

Select a shape Choose Circle, Rectangle, Ellipse, Straight Slot, or Double Circle.

Add measured points Enter X/Y points from probing. Set probe diameter (Ø) so calculations match your setup.

Tap Calculate Get center coordinates and key dimensions (diameter/width/height/angle). Use the result as your move-to target.

Screenshot: Fit tab — add assets/cnc-screenshot-fit.png

Enter nominal size Type your dimension in mm.

Select tolerance grades Pick hole/shaft types (e.g., H7 / h6) from the menu.

Read the fit outcome See the tolerance bands and the resulting fit classification at a glance.

Screenshot: Weight tab — add assets/cnc-screenshot-weight.png

Pick unit + material Metric/Imperial, then choose a material preset (steel, aluminum alloys, copper, etc.).

Select a shape Plate, tube, ring, round bar, flat bar, and more.

Enter dimensions The weight result updates as you type.

Screenshot: Tolerances tab — add assets/cnc-screenshot-tolerances.png

Open Tolerances Use the General Tolerances tab for quick shop-floor reference.

Size tolerance Enter nominal size, choose type (Linear / Radius / Angular) and grade (f/m/c/v).

Geometric tolerance Choose a geo type (straightness/flatness, perpendicularity, runout, etc.) and grade (H/K/L) to view the result.

Who it’s for

Job shops

Speed up everyday centering and quick checks without spreadsheets.

Prototype & R&D

Iterate setups faster and keep measurement math consistent across runs.

Training

Help new operators understand fits, tolerances, and geometry results.

FAQ

Does the app need the internet?

No. Core calculations work offline.

Does it collect any data?

No developer analytics or tracking SDKs are used. See the full policy on the Privacy page.

Can I use it on iPad?

Yes — the UI is built for both iPhone and iPad workflows.

Where do I report a bug or request a feature?

Email wangning.engineer@outlook.com.

Download

Ready to use it on the shop floor?

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