Short version: GridCraft matched Excel's saved value on 1,842 of 1,968 formulas across 15 of Microsoft's own templates, and 13 of the 15 files were perfect. It's free, while Microsoft 365 Personal costs $99.99 a year. It also has a real #SPILL! bug that a save can write into your file, and it can't display Khmer yet.
▶ Full video: https://youtu.be/18kJ7HuIvnQ
What is GridCraft?
GridCraft is Excel rebuilt from scratch in Rust by storytold, the team behind ArtCraft and WordCraft.
- License: MIT or Apache-2.0
- Runs on: Mac, Windows, Linux and in the browser
- Features: reads and writes Excel files, with over 500 functions, PivotTables and charts
- Stars: about 7,300 on GitHub, one month after launch
I tested version 0.17.0 on a Mac mini M4 with 16 GB of RAM. The download matched its published checksum and was notarized by Apple.
Test 1: 15 real Excel files
Last month's reviews said it opened about half of people's files, so I retested on 15 templates straight from Microsoft: budgets, a loan schedule, a Gantt chart and PivotTables.
The CLI has a useful check for this:
gridcraft-cli check your-file.xlsx
It recalculates every formula and compares the result with the value Excel saved in the file.
One fairness detail: the templates use TODAY(), so my first run showed fake date mismatches. I froze those cells at Excel's saved value so old dates wouldn't count as errors.
- Overall: 1,842 of 1,968 formulas match (93.6%)
- Perfect files: 13 of 15, including the loan schedule (875/875) and Gantt chart (187/187)
The two failures are very different:
-
Stocks sheet (expected): it needs Microsoft's online data service, so you get
#NAME?. -
Budget wheel (a real bug): an old-style table reference,
Expenses[Amount], gets implicit intersection in Excel. GridCraft returns#SPILL!, and the chart shrinks to one slice.
Some files also warn about skipped features, such as a PivotTable with calculated items.
Test 2: Save it, then open it elsewhere
There's no Excel on my Mac, so LibreOffice opened every file GridCraft saved. It recalculated 4,117 cells, and only 46 differed, most of them tiny rounding digits.
The bad part: after GridCraft saves the budget wheel, LibreOffice shows #SPILL! too. The save rewrote the formula. Keep a copy of your files before saving over them.
Test 3: 100,000 rows vs LibreOffice
| Task | GridCraft | LibreOffice |
|---|---|---|
| CSV to Excel file | 0.40 s | 1.35 s |
| Recalculate 100,000 formulas | 1.83 s | 1.06 s |
So it isn't faster at everything. The app also opened all 800,000 cells in about 1.3 seconds, and every total matched a separate check in Python.
Test 4: Power features
On a made-up coffee shop's 2026 sales, these all worked: tables, data bars, XLOOKUP, LAMBDA, PivotTables, charts and Solver.
It's still missing three Excel habits: tables don't grow when you add rows, formulas don't fill down as calculated columns, and pivot charts include the Grand Total.
Test 5: Let an AI build the sheet
GridCraft exposes its commands to AI agents. I gave Claude Code one prompt: build a monthly budget for a student in Phnom Penh.
- Time: 57 seconds
- Tool calls: 31
- Result: real formulas, red cells for overspending and a chart
It also checked its own work with screenshots before it stopped.
The test that matters to me: Khmer
I'm in Cambodia, so I made a mini mart sheet in dollars and riel. The exchange-rate formulas worked, but Khmer text and the riel sign (៛) showed as empty boxes, and in the PDF the riel sign turned into a Chinese character. The Khmer text is saved correctly in the file. GridCraft just can't draw it yet.
If your language needs complex text shaping, test that first.
Verdict
For budgets, school work and simple sheets, I'd try it today, and I'd keep a copy of my files. If you need Khmer, or your business lives in Excel, wait a few versions. New releases come every day or two, so these results will age quickly.
What's the one spreadsheet you'd test first?
Links
- GridCraft on GitHub: https://github.com/storytold/gridcraft
- GridCraft website: https://getartcraft.com/apps/gridcraft
- Full video: https://youtu.be/18kJ7HuIvnQ
AI-assisted disclosure: I used an AI assistant to help structure this write-up. The tests and timings are my own (Mac mini M4, 16 GB, GridCraft 0.17.0, LibreOffice 26.8.2, Claude Code with Opus 5.5, November 9, 2026). Price from microsoft.com on the same date. Not sponsored by storytold or Microsoft.
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