$1,851/yr
per named user for Minitab
Sold through a sales form. A shop with one quality person pays for DOE, regression and reliability tools to get a control chart.
Published single-user price, 2026For the quality person at a 5-50 person machine or fab shopFor small machine and fab shops
Every feature's Cpk, on one board your customer can read.
Paste the readings from your CMM or calipers. Cpkboard draws the X-bar and R chart, flags the points that break a rule, and gives you the Cp, Cpk, Pp and Ppk your customer asked for, with the formula shown under each one. In the browser, on any machine, nothing to install.
125 readings in 25 subgroups. Nothing you paste here leaves your browser.
Cp1.79within, R̄/d₂
Cpk1.67within, R̄/d₂
Pp1.55overall, s
Ppk1.44overall, s
X-bar chart
Range chart
Histogram against spec
Western Electric rules
- Rule 1 Point 19 is beyond a control limit
- Rule 2 2 of 3 points beyond 2 sigma, at point 19
- Rule 3 4 of 5 points beyond 1 sigma, at point 21
Built for the features small shops get asked about
Turned diameters and boresHole positions and true positionSheet metal flats and bendsMolded and cast dimensions
Charting by hand today
The customer wants a Cpk on the shaft diameter with the PPAP. By Friday.
So someone types 125 readings into the spreadsheet a former employee built, hopes the formulas still work, and sends a number the customer's quality engineer recomputes anyway. Cpkboard takes the readings as they are and gives you the chart, the indices and the report on one page.
2 answers
for the same Cpk, Excel vs the customer
"I have tried replicating results from Minitab in Excel and have gotten different answers consistently." Within sigma or overall sigma, biased or not: a spreadsheet doesn't say which one it used.
Quality technician on r/Metrology, 2025$379/PC
for an add-in that still needs Excel
One license per computer, the right Excel version on each, and the chart lives in whoever's workbook it was made in. "Excel tends to freeze, and I have to restart."
Add-in store prices and reviews, 2026How it works
From readings to a report in four steps.
Paste or upload
From Excel, a CMM export or the data collector. One subgroup per line.
The chart draws itself
Limits from your data, rule violations marked in red, histogram against spec.
Every feature on one board
Each job's features with their latest Cpk, green, amber or red.
Send the report
PDF or a link with your logo. The customer sees the chart and the formulas.
The feature board
"A graph for every feature, with every part on it."
That's how a quality tech on Reddit described what he couldn't get out of Excel. It's the board: one row per feature, the last 20 subgroups as a sparkline, and the Cpk that goes on the PPAP.
Jobs, parts, features
Organized the way your travelers are. Click a feature for its full chart.
Charts update as readings land
Paste today's five parts and the point appears on the chart.
Rules flagged, not buried
Western Electric rules 1-4 marked in red on the chart and on the board.
Same feature, next job
Copy a feature's spec and subgroup size to the next revision.
Job 4471 · Housing, rev CPPAP due Fri
FeatureMachineLast 20Cpk
Shaft Ø .500Lathe 21.67
Bore Ø 1.250Lathe 21.41
Flange thicknessMill 11.08
Hole positionMill 11.52
Keyway widthMill 30.94
Thread pitch ØLathe 11.38
Click a feature for its X-bar/R chart, histogram and the readings behind every point.
Your readings, as they are
Match the CMM export once. Every file after charts itself.
No retyping and no template to keep alive. Upload the CSV your CMM or data collector already writes, match the columns one time, and Cpkboard remembers.
CSV and Excel
Zeiss CALYPSO, Mitutoyo MCOSMOS, PC-DMIS and plain spreadsheets.
Columns remembered
Characteristic, actual, nominal, tolerances, operator, time.
Watched folder (Pro)
Point it at the export folder and new readings chart themselves.
Nothing silently dropped
Cells that aren't numbers are counted and shown, never hidden.
Import · Zeiss_CALYPSO_export.csv7 columns matched
Characteristic→Feature nameActual→ReadingNominal→NominalUpperTol→USLLowerTol→LSLDateTime→Measured atOperator→OperatorComment→SkipNext time this file lands, the matches are remembered and the charts update themselves.
Reports your customer can check
The capability report, with the math on it.
Cpk from R-bar over d2. Ppk from the overall standard deviation. Both on the page, so the customer's quality engineer stops recomputing your numbers.
Your logo and job number
A PDF or a link that opens on their phone.
Formulas shown
Every index names its sigma estimate and its constants.
Readings behind every point
Click a point in the report to see the five readings in it.
CSV export
The data goes with you, always.
Rourke Machine · Capability report
Cpk 1.52Cp1.58
Cpk1.52
Pp1.49
Ppk1.44
Mean0.50011
σ within0.00042
Formulas: Cpk from R̄/d₂, Ppk from overall s. AIAG SPC 2nd ed.0 points out of control
How it compares
Where Cpkboard wins, and where it doesn't.
The same charts and indices as the Excel add-ins and Minitab, without Excel or a license key. And three rows where the other tools are the right call.
| Cpkboard | Excel add-ins (QI Macros, SPC for Excel) | Minitab | |
|---|---|---|---|
| Price | $29/mo for one user, $90/mo for the whole shop | $329-379 one-time, per computer | $1,851 per named user per year |
| Runs on | Any browser: Mac, PC, shop tablet | Excel on Windows or Mac, matching version | Windows install, or web with a license |
| Getting started | Paste readings, chart in seconds | Install, then build your workbook | Install, training, sales call for pricing |
| Many features at once | One board, every feature's Cpk | One chart per worksheet | One project file at a time |
| Sharing with a customer | PDF or link with the formulas | Email the workbook | Export to PDF |
| Capability formulas shown | Under every number | In the help file | In the help file |
| Gage R&R | Pro plan, AIAG MSA 4th ed. | Yes | Yes |
| DOE, regression, hypothesis tests | No. Keep Minitab for experiments | Some | Yes, the full set |
| Works with no internet | No | Yes | Yes (desktop) |
| One-time license | No. Monthly or yearly | Yes | No |
Is it for you?
Built for one kind of shop.
Cpkboard is for you if
- You run or do quality at a machine, fab or molding shop with 2 to 50 people.
- Customers ask for Cpk, control charts or a PPAP, and ISO 9001 or IATF 16949 is on your wall or on your customers'.
- Your readings come from a CMM, calipers or a data collector and end up in Excel.
- You want the chart on the shop tablet and the report on the customer's phone.
- Minitab's price or the spreadsheet's fragility is what stopped you.
Not a fit if
- You run designed experiments, regression or reliability studies. Keep Minitab or JMP.
- Your shop floor has no internet. Cpkboard runs in the browser.
- You need validated software for medical devices under 21 CFR Part 11. We don't claim that.
- You want a one-time license. Cpkboard is $29 a month or $290 a year.
Pricing
Two plans. No seats to count on Pro.
No setup fee, no training package, no license keys.
Shop
$29per month
Billed monthly. Cancel anytime, no setup fee.
Start with Shop- 1 user
- Up to 25 features on the board
- X-bar/R, X-bar/S, I-MR, p, np, c, u charts
- Cp, Cpk, Pp, Ppk with the formula shown
- Western Electric rules flagged
- Paste or upload CSV and Excel
- Shareable capability reports (PDF and link)
- Email support, answered the same business day
No card needed today Export everything, anytime
ProWhole quality team
$90per month, per company
Billed monthly. Cancel anytime, no setup fee.
Start with Pro- Unlimited users, one price
- Unlimited features and jobs
- Everything in Shop
- Gage R&R and Type 1 gage studies
- Scheduled imports from your CMM folder
- Alerts when a point breaks a rule
- Customer-facing report links with your logo
- Audit log for every reading and edit
No card needed today Export everything, anytime
One lot of 200 shafts rejected at the customer$3,800
Sorting, rework and the truck back$1,100
Cpkboard Shop for a year$290
Catch one drift on the chart before the lot ships, and the year is paid for twice over.
FAQ
Common questions
Are the numbers the same as Minitab's and the AIAG manual's?
Yes, and we show the formula under every number so you can check. Cp and Cpk use within-subgroup sigma (R-bar over d2, or MR-bar over 1.128 for individuals). Pp and Ppk use the overall sample standard deviation. Control limits use the standard A2, D3 and D4 constants. Gage R&R follows the AIAG MSA 4th edition average and range method. If a customer's quality engineer wants to recompute a value by hand, the report gives them everything they need.
Does it run on a Mac, or on the shop floor tablet?
Yes. Cpkboard runs in any modern browser, so it works on a Mac, a Windows PC, an iPad or the tablet next to the CMM. There's nothing to install, no Excel version to match and no license key to move when a laptop dies.
How do my readings get in?
Three ways. Paste them from Excel or a text file, like the demo on this page. Upload a CSV or Excel export from your CMM software (Zeiss CALYPSO, Mitutoyo MCOSMOS, PC-DMIS and the like). Or on the Pro plan, point Cpkboard at the folder your CMM exports to and new readings chart themselves.
Which charts does it make?
X-bar/R, X-bar/S and I-MR for measurements. p, np, c and u for defect counts. Histograms with spec limits, and Cp, Cpk, Pp and Ppk for every feature. Pro adds Gage R&R (crossed, average and range) and Type 1 gage studies.
Will it do DOE, regression or hypothesis tests?
No. Cpkboard does control charts, capability and gage studies for the parts you make, and does them well. If you run designed experiments or regression, keep Minitab or JMP for that work.
Can my customer see the chart?
Yes. Every feature has a report you can send as a PDF or as a link with your shop's logo. The customer sees the chart, the capability indices and the formulas. They don't see your other jobs or customers.
When does my account open, and when am I charged?
We're opening accounts to shops in small groups this fall. You reserve a plan now with no card. We email you the day your account opens, and billing starts when you first log in. Cancel anytime from your account.
What happens to my data if I leave?
Every reading, chart and report exports to CSV and PDF from your account, anytime. Your data is yours.
More about billing on the pricing page, or email hello@cpkboard.com.
Put your first feature on the board tonight.
Create your account in two minutes. Paste last week's readings or send us a CMM export, and the chart and Cpk your customer asked for are ready to send.
Create your account
From $29/mo No card today