LumenSheetsSpreadsheets

A spreadsheet that checks its own work.

Profile the export, fix the types, write real formulas and chart the answer. Then it recomputes every row and re-derives the totals a second way.

Download freeWatch the agent work

Free to download, free to model in. AI features draw on your allowance.

Opens
.xlsx · .csvAnd the exports that are almost neither
Writes
Real formulasNot pasted-in results
Modelling costs
Nothing, everA free account, no card
Runs
On your machineYour data stays local

01What it does

It reads the data before changing it, and again after.

The most dangerous spreadsheet is one that is confidently wrong. Profiling comes first, and verification comes last.

01It checks itself

It reads the numbers back.

After building, it recomputes the values and re-derives the totals a second way instead of trusting the formula it just wrote, then fixes what does not reconcile.

  • Recomputes rather than trusting its own formula
  • Re-derives totals independently
  • Reports what did not reconcile instead of hiding it

02The export is never the data you wanted

Numbers stored as text, duplicate rows, blank keys, three spellings of the same customer. It profiles the sheet and tells you what is wrong before it changes anything.

Retype a whole column in one step

03Real formulas

Written into the cell, not pasted as a number, so the model still works when the data changes.

See what feeds a cell, and what depends on it

04Charts that read as an answer

Chosen for the question and labelled properly, not eleven colours and a legend.

Legible in light and dark

05Your library

The cost basis lives in a document. It reads it, so “margin” means the same thing everywhere.

Documents and PDFs read as sources

06Dashboards

Tiles, slicers and filters over the finished model, shared as a link.

For someone with nothing installed

02LumenAgent in LumenSheets

It builds the model, and stops to ask.

It profiles the sheet, reads the cost basis out of your library, and waits for you before it deletes a single row. Decline and it flags them instead.

Understand
8,412 rows, 14 columns, and the agreed cost basis
Prepare
Types fixed; duplicates removed or flagged
Build
Real formulas filled down, and the chart by quarter
Verify
Every row recomputed, the total re-derived a second way
LumenAgent · LumenSheets
Clean this export, build the margin model, chart it by quarter, and write the board memo.
Reading the exportread_data8,412 rows · 14 columns
Profiling the sheetanalyze_sheet3 numeric columns stored as text · 214 duplicate rows · 61 blanks
Searching your library for “margin model”search_library
Pricing model FY26.xlsxCost assumptions.docx
Reading the cost basisread_library_documentSo margin means the same thing here as everywhere else
Needs your approval

Delete 214 duplicate rows?

Matched on customer, quarter and invoice number. Everything so far has only read the sheet. This is the first change to it.

03The full toolkit

Everything LumenSheets does, and all of it free.

No watermark, no upsell in the middle of a model.

Read & profile

Know the data before changing it.

  • Types, blanks, duplicates, live statistics
  • What feeds a cell and what depends on it
  • Group and summarize without a pivot first
  • Find rows by condition, across sheets

Prepare

Shape it into something usable.

  • Retype a column in one step
  • Duplicates and blanks removed or flagged
  • Split, merge, transpose, map values
  • Refreshable external data

Build

Real modelling.

  • Formulas written into cells, filled down
  • Named ranges and lookups
  • Goal seek for the input you need
  • AI columns to classify, extract, summarize

Visualize

The answer, not the data dump.

  • Charts chosen for the comparison
  • Pivots that stay live
  • Dashboards with tiles, slicers and filters
  • Conditional formatting where the eye should go

Verify

The part most tools skip.

  • Every value read back after building
  • The total re-derived a second way
  • Quality and performance checks on dashboards
  • Colour and label checks on every chart

Hand it on

Out of the workbook.

  • .xlsx and .csv, formulas intact
  • A memo, a deck or a report from the same figures
  • A view-only dashboard link
  • The whole clean-up as a LumenFlow (Pro and above)

04Works with the rest

The numbers usually have to leave the sheet.

The memo, the deck and the sheet cannot drift apart.

  1. Starts here

    An 8,412-row export

    Typed as text, duplicated, and disagreeing with the contract. Profiled before anything is touched.

  2. Reads

    The supplier contract

    The agreed cost basis is in a PDF. It is read, not guessed at.

  3. Hands off

    The board memo

    Written by LumenDocs, with every figure cited to the cell it came from.

  4. Hands off

    The quarterly deck

    Same numbers, built by LumenSlides with its own charts and speaker notes.

05Questions

Common questions

Does it write formulas or paste in the answers?

Real formulas, written into the cells and filled down, so the model still works when the data changes.

Will it delete rows without asking?

No. The first change that removes data pauses and asks. Decline and it flags the rows instead of deleting them.

How does it know its answer is right?

It reads the computed values back and re-derives the totals a second way. Anything that does not reconcile is reported, not hidden.

Can it open my existing spreadsheets?

Yes. .xlsx and .csv, including the awkward exports that are nearly neither. Formulas, formats and multiple sheets come through.

Is there a row limit?

Not a fixed one. The ceiling follows your machine’s memory: about 2 million rows of a dozen columns on a 16 GB machine, and never more than 5 million. An .xlsx export is held to Excel’s 1,048,576 rows, with .csv for anything larger. Opening, editing and modelling are free; only the AI features draw on your allowance.

Trust the model again.

One download, every editor, and an agent that asks before it deletes anything.

Download freeSee pricing

Free to download, free to model in. AI features draw on your allowance.