Logic & Automation

Excel gives you SUM, VLOOKUP and IF. What it can’t give you is a function that works the way your business works. So you build elaborate nested formulas. Copy the same logic across thousands of rows. Train people on “the cell in column F that you must never touch”.

LAMBDA functions change that. They let you define business logic once and reuse it everywhere.

That might mean a single function that applies your exact pricing logic. One that validates and cleans data before it creates problems downstream. One that shapes data so your charts don’t break. Or one that handles the edge cases and aggregations your team runs into every week.

The result is formulas people can read. Calculations that stay consistent. And time back where it belongs.

For more complex logic, Python in Excel extends what LAMBDA does, for the cases where the complexity warrants it.

Compatibility

» Requires Excel 365. Also works in some Excel 2021 versions (depending on build).
» Not sure? Type =LAMBDA in any cell to check. If Excel recognizes it, you’re set.
» Don’t have it? No problem. I can build the same logic in VBA instead.
» Python in Excel requires a paid Microsoft 365 subscription with connected experiences enabled. In practice, LAMBDA covers most business needs. Python becomes relevant when the complexity warrants it.

I map the logic before anything is automated.

I work with you to trace the rule or calculation end to end: what inputs it needs, what happens at the edges, what it should do when something goes wrong. I document the logic until there is no ambiguity.

I build, you test, we refine.

I develop the LAMBDA function using your real scenarios. You test it against actual data and the edge cases your business sees. When something doesn’t work as expected, we document why, so you understand what the function assumes and where it might fail. We iterate until it behaves correctly.

I deliver and stay close.

You receive a ready-to-use function with clear documentation explaining what it does and how to apply it. You own it, understand it and can modify it when the business logic changes. I walk your team through its use and when something shifts, a new rule, an edge case you haven’t seen before, a question three months later, you pick up the phone and I’m there.

⬤ Tier I (€250)

Encoding one specific, complex business rule (e.g., custom pricing logic or a data validator) into a single, clean formula.

Typical delivery: 2 weeks.

⬤ Tier II (€650)

Three related custom functions built as a seamless set with shared logic. Replaces a cluster of nested formulas or repeating manual steps.

Typical delivery: 2-3 weeks.

⬤ Tier III  (€1,000–€1,750)

A fully scoped architecture of custom functions covering an entire department’s business logic, advanced conditions and deep edge-case handling.

Typical delivery: 3–6 weeks.

Team training, full documentation and structured handover are included for all tiers. Scope and price are agreed before any work starts. There are no hidden costs.

Beyond one-off projects: Ongoing support, workbook upgrades, longer engagements and team training are available. These are scoped transparently based on your needs.

All engagements are covered by a confidentiality agreement. Nothing is shared without your written consent.

Pro bono work is offered to nonprofits (see “About Me”).

Most LAMBDA functions are written to impress. Mine are written for the people who inherit the file and use it daily.

With me, you get:

⬤ Help deciding which logic to automate and which to keep flexible.
⬤ Functions structured so your team can modify them when the business logic changes.
⬤ Documentation that explains not just what the function does, but what it assumes and what to watch for.

This is Phronesis. The practical wisdom to know which rules belong in code, which need to stay flexible and how to structure both so your team can maintain them. That’s what makes the work sustainable and the solution something your team will actually use.