What I don't do, and where to check everything I claim

This page exists because I am asking you to send an internal file to a stranger. The only sensible response to that is suspicion, so here is the boundary of what I deliver, every source behind every claim on the other page, the free tools to do this work yourself, and who else does it.

Nothing here is a sales page. If you leave and go to ISOBudgets or download the NIST form and do it yourself, that is a fine outcome, and section 4 is written to make it possible.

1. The full checklist, all 47 checks

The record I produce is built around the NIST Office of Weights and Measures Software Verification and Validation form, published as GLP 15 (2019), Appendix A, free from NIST. Download it and hold it next to my sample. It is a federal document, not something I invented, and it is how you can judge my work without taking my word for anything.

It has 47 checks. Of those, 30 I answer from the file itself, 6 I gather the evidence for and leave the judgment to you, and 11 only you can answer. How many come back answered depends on the workbook: some checks will not apply to your file at all, and two need things I ask for separately, namely last year's version of the same workbook and your accredited scope.

Every one of the 47 appears in the record, including the ones I cannot answer. A checklist with the awkward rows quietly removed is worth nothing.

A. Software Inspection

Check	What it asks	Who answers it
A1	Spreadsheet is clear and makes sense	I gather the evidence, you judge it
A2	There are instructions for use	I answer it from the file
A3	Instructions and data input appear on the visible portion of the first worksheet	I answer it from the file
A4	Data-entry fields are labeled and color coded (avoiding red and green)	I answer it from the file
A5	The Standard Operating Procedure used is clearly specified	I answer it from the file
A6	The number of digits to be rounded to is specified	I answer it from the file
A7	The user is warned whenever data-entry fields are left blank	I answer it from the file
A8	Data-entry fields are blank when opened, so old data is not reused	I answer it from the file
A9	The software opens at the right location within the file	I answer it from the file
A10	Unused fields/cells are locked	I answer it from the file
A11	Rows/columns the operator need not see are hidden	I gather the evidence, you judge it
A12	Unused sheets are removed	I answer it from the file
A13	Worksheets are named appropriately	I answer it from the file

B. Mathematical Specification

Check	What it asks	Who answers it
B1	The correct SOP is used	Only you can answer it
B2	The formulae and methods chosen from that SOP are specified	I answer it from the file
B3	Sources and references for formulae are specified	I answer it from the file
B4	The SOP, its methods and formulae are appropriate to the level of precision	Only you can answer it

C. Code Review

Check	What it asks	Who answers it
C1	The formulae in the fields exactly match the procedure	Only you can answer it
C2	Repeated calculations appropriately reference the correct cells	I answer it from the file
C3	Calculations, tested with reference data, show appropriate accuracy	I answer it from the file
C4	Rounding is done at the appropriate locations in the file	I answer it from the file

D. Numerical Stability

Check	What it asks	Who answers it
D1	Calculations are stable with large numbers and small differences	I answer it from the file
D2	Fields are categorized as Number and not General when appropriate	I answer it from the file
D3	Number cells are locked to an appropriate number of decimal places	I answer it from the file

E. Component Testing

Check	What it asks	Who answers it
E1	Conditional logic cells handle negative values properly	I answer it from the file
E2	Conditional logic cells withstand a boundary value test	I answer it from the file
E3	Each macro used is functional	Only you can answer it
E4	Each command/button is functional	Only you can answer it
E5	Combinations of interdependent macros are functional	Only you can answer it
E6	Plotted graphs are accurate	I gather the evidence, you judge it
E7	Plotted graphs and their axes are properly labeled	I answer it from the file
E8	Worksheets/reports print properly, if needed to	I answer it from the file
E9	Conditional (color and non-color) formatting is functional	I gather the evidence, you judge it

F. Numerical Reference Results

Check	What it asks	Who answers it
F1	Look-up tables and lists match the latest calibration report	Only you can answer it
F2	Uncertainties match the latest Scope	I answer it from the file
F3	Values that reference another workbook are dated	I answer it from the file
F4	Behaviour is as intended when a master list's date is updated	I gather the evidence, you judge it

G. Embedded Data Evaluation

Check	What it asks	Who answers it
G1	Embedded data (conversion factors, reference values) is correct	I gather the evidence, you judge it
G2	The evaluation of the embedded data is dated and documented	I answer it from the file

H. Back-to-Back Testing

Check	What it asks	Who answers it
H1	Newer and older spreadsheets agree down to intermediate calculations, dated	I answer it from the file

I. Analysis Without Computer Assistance

Check	What it asks	Who answers it
I1	Hand calculations agree with the spreadsheet, or differ insignificantly	I answer it from the file

J. Security

Check	What it asks	Who answers it
J1	Equation and calculation cells are protected against inadvertent editing	I answer it from the file
J2	Cells are locked in place and cannot be moved or dragged	I answer it from the file
J3	Confidentiality of passwords is appropriate	Only you can answer it
J4	Files are backed up automatically	Only you can answer it
J5	Additional back-up is available at alternate facilities	Only you can answer it
J6	Files on network drives cannot be accidentally deleted	Only you can answer it

2. What I do not do, and what that means for you

Read this column on the right rather than the one on the left. A list of things I refuse is only useful if it tells you what you are still on the hook for.

I do not	Which means
Decide which contributors your measurement needs	I check your budget against the contributors ILAC P14 5.4 expects, which are repeatability, resolution, reference standard, drift and environment, and I report which are absent. Whether an absent one genuinely does not apply to your measurement is metrology judgment, and it stays with you. I show gaps. I do not decide which of them matter.
Answer 11 of the 47 checks	Your record arrives with blanks in it: backups, password handling, macro behaviour, whether the correct procedure was chosen. It is not a finished document until you complete those. I leave them visible rather than filling them in, because no examination of a file can answer them.
Test macros, buttons, or printed output	GLP 15 section E leaves those to the laboratory and so do I. I detect that macros are present; I do not run them or judge whether they work.
Know what your workbook was meant to do	Section 3 of the record is a requirements specification I reverse-derived from the file, because almost no lab has one written down. If it misstates your intent, every test below it is measuring against the wrong specification. Reading that section is the one step you cannot delegate to me, and it is the single most important thing on this page.
Read legacy `.xls` files	The formula layer of that format cannot be read reliably. Open it in Excel, Save As `.xlsx`, and nothing in the file changes. Ten seconds.
Validate your LIMS	Waters, LabWare and LabLynx do that and they are good at it. I work on the side workbooks that feed it, which is a different problem.
Work under 21 CFR Part 11 or pharma CSV	Different regulator, different liability, much heavier documentation. If that is your world, see section 5.
Certify, attest, approve, or accredit anything	No body accredits validation providers. Not A2LA, not anyone. If a vendor implies otherwise, that alone should worry you. Your technical manager's signature is what gives the record standing, not mine.
Predict what your assessor will conclude	I do not control your assessor, and anyone selling "guaranteed to pass" is selling something they cannot deliver.
Give an opinion on results you already issued	I validate software. I do not bless data that has already left the building. If I find something that affects released results, I tell you and nobody else, and what you do about it is entirely your decision.
Have a track record	No record I have produced has been through an accreditation assessment yet. I started in 2026. Being able to complete a NIST form is not the same as your assessor accepting it, and I have no evidence about the second thing. That is the honest reason the first file is free.

3. Where every claim comes from

The rule I work to is that I never state a fact I have not read the source for, and that I say which sources are primary and which are not.

Claim	Source	Kind
Uncertainty must be evaluated for each measurement function	ISO/IEC 17025:2017 clause 7.6. The standard is not free to redistribute, so I describe what it requires in my own words rather than quoting its text. The method I actually test against is the GUM, below, which is free and public.	Paid standard
How an uncertainty budget is built and combined	JCGM 100:2008, the GUM, free from BIPM. This is the method every budget implements and what I test against.	Primary, free
Expanded uncertainty to at most two significant figures; coverage factor and coverage probability both stated	ILAC P14, free. A2LA's R205 defers to it.	Primary, free
A per-file software validation form exists and is expected	NIST GLP 15, and NIST IR 8250.	Primary, free
Uncertainty budgets missing required components rank second among cited A2LA deficiencies	Heather Wade Group, corroborated by In Compliance Magazine. These are two secondary sources, not A2LA's own publication. I have not been able to verify the ranking against A2LA directly, and I would rather you knew that than took the number at face value.	Secondary
ISO 17025 consulting commonly runs $100 to $250 an hour	Published industry summary. A range, not a quote, and not a claim about any particular consultant.	Secondary
Your accreditation scope and the range in my first email	Your own certificate in the A2LA public directory, with the date I retrieved it recorded.	Primary, free

4. How to do all of this yourself, for nothing

Every tool needed to do this work is free, and most labs simply do not have the hours. If you do have them, here is the path, in order.

The honest catch: doing one file properly this way is most of a day the first time, and you have more than one file. That gap is the only reason I have a business, and I would rather say so than pretend the free path does not exist.

5. Who else does this, and when you should use them instead

Prices below were checked in July 2026 and will drift. Verify before you buy anything on my say-so.

ISOBudgets

Go to them, not me, if you do not have an uncertainty budget yet. They build budgets; I document and verify budgets you already have. Different product, same reader. They sell uncertainty calculators from $19 to $49, instrument-specific budget templates for particular calibrators and multimeters at $1,500 to $2,500, and a training bundle at $197. Consulting is quote-based with no public price. They say they have worked with more than 3,000 laboratories since 2011. isobudgets.com. Their blog is fifteen years of free writing aimed squarely at you and is worth reading whether or not you ever buy anything.

The 17025 Store, now trading as Uncera

Sells an Equipment Uncertainty Calculation Excel sheet at $49, reduced from $99, with a step by step guide. A template to build with, not a validation of what you have. uncera.com.

Pharma and 21 CFR Part 11 specialists

If you are FDA-regulated, I am the wrong supplier and you should not hire me. Ofni Systems sells ExcelSafe, which adds audit trails and electronic signatures to Excel, and does validation packages around it. That world is far heavier and considerably more expensive than anything on my price list, and correctly so, because the regulator is different. ofnisystems.com.

A general ISO 17025 consultant

Commonly $100 to $250 an hour. More expensive than me and much broader: a good one will make the metrology judgments I explicitly refuse to make, write your quality manual, and sit with you through an assessment. If what you actually need is someone to decide what belongs in your budget, hire one of them.

LIMS validation vendors

Waters, LabWare and LabLynx validate the central system. That is a real and different job. Nobody in that market is interested in the thirty side workbooks that feed it, which is the entire reason I exist.

Doing nothing

Sometimes the right answer. If your scope has three CMC lines, you have three budgets, and this is not a spreadsheet problem. The labs this helps are the ones with more calculation files than anyone can remember building.

6. What happens to your file

That last point deserves saying plainly, because it cuts against me: asking you to look inside a workbook is asking you to find out whether you have a problem. Some labs would rather not know. I would rather write that down here than discover you were worried about it after you had already decided not to reply.