Quick verdict
Pick SheetAI if…
- You live in the formula bar and want AI as a primitive (
=SHEETAI(...)). - You want to bring your own OpenAI API key and pay for usage directly.
- Your main need is text intelligence: extract, classify, summarize, image generation.
- You want pay-as-you-go token packs over fixed plans.
Pick SheetBrain if…
- You want a free, unlimited, deterministic audit for broken refs, visible formula errors, mixed types, duplicate VLOOKUP keys, formula pattern outliers, and missing copied formulas — no AI quota at all (Detector Set v0.4).
- You want AI-powered schema-aware Repair after columns move or get renamed.
- You prefer a guided sidebar with Generate / Explain / Debug / Check / Repair tabs.
- You want one flat $9/mo price with all AI features included, no API key.
Side-by-side feature comparison
| Feature | SheetAI | SheetBrain |
|---|---|---|
| Delivery surface | Custom sheet functions | Sidebar add-on (5 tabs) |
| Formula generation | Yes (via =SHEETAI()) | Yes (Generate tab) |
| Formula explanation | No dedicated | Yes (Explain tab) |
| Root-cause Debug | No | Yes — finds why a formula is wrong |
| Free deterministic Sheet Check | No | Yes — unlimited, no AI quota |
| Schema-aware Repair (after column moves) | No | Yes — preview-before-apply rewrites |
| Text extract / classify / summarize | Yes — =SHEETAI_EXTRACT, =SHEETAI_CLASSIFY, =SHEETAI_SUMMARIZE | No |
| AI image generation | Yes — =SHEETAI_IMAGE | No |
| BYO-API-key tier (unlimited) | Yes — published on their pricing page | No |
| Pay-as-you-go top-ups | Yes — token packs (see their pricing page) | No — fixed monthly plan |
| Free tier (core gen) | Limited — see SheetAI pricing | 15 AI calls / mo + unlimited deterministic scans |
| Paid entry price | See SheetAI pricing for current tiers | $9/mo Pro (1,000 AI calls) |
| Works on free Gmail™ | Yes | Yes |
Where SheetAI is genuinely better
It is the formula-primitive choice
If your habit is to type formulas, SheetAI fits that habit. =SHEETAI("Translate to French", A2) in a cell, drag the formula down a column, you have a translation column. SheetBrain does not have an equivalent custom function for AI tasks; you open the sidebar instead. Some workflows are a worse fit for sidebars than for the formula bar.
BYO-API-key gives a real "unlimited" option
SheetAI's Unlimited tier asks you to provide your own OpenAI API key. They do not eat the AI cost, so they can honestly call it unlimited. SheetBrain bundles AI cost into the $9/mo plan, which means there is a 1,000-call ceiling above which you would need a fix that does not exist yet. For genuinely high-volume single-user AI work, SheetAI's BYO model is more honest. SheetAI's pricing page has the current Unlimited price.
Text intelligence is broader
SheetAI ships =SHEETAI_EXTRACT, =SHEETAI_CLASSIFY, =SHEETAI_SUMMARIZE, =SHEETAI_LIST, =SHEETAI_FILL, and image generation. SheetBrain does not currently ship custom functions for any of these. If your work is mostly "categorize 5,000 rows of free-text feedback", SheetAI is the closer match.
Where SheetBrain is genuinely better
The free deterministic Sheet Check
This is SheetBrain's actual moat. The Check tab runs Detector Set v0.4 — no AI calls, no quota — with six detectors: broken_reference (cells displaying #REF! plus lookup formulas with column or row indexes outside the referenced range, with auto-fix for the index case), visible_formula_error (formula cells returning common visible errors), mixed_text_number (mixed-type columns), duplicate_lookup_key (duplicate VLOOKUP keys), inconsistent_formula_pattern (formula pattern outliers), and missing_formula_pattern (missing copied formulas). SheetAI does not have anything in this category. Schema drift after a column moves is handled separately by SheetBrain's AI-powered Repair tab on the $9/mo Pro plan.
Schema Repair after column moves
If a column gets renamed or moved, your VLOOKUPs silently start computing the wrong thing. SheetBrain captures a schema snapshot when you use Generate or Debug, then on click of Repair surfaces every formula whose target shifted — with safe rewrites you preview and apply one-by-one. Schema drift is the bug class manual auditing cannot catch; SheetAI cannot catch it either. Neither can Formula Bot or Gemini for Workspace.
Sidebar gives a guided flow
SheetAI hands you primitives and trusts you to compose them. Generate / Explain / Debug / Check / Repair as five sidebar tabs walks a typical user from "I need help writing a formula" to "I want to know why mine returns the wrong value" to "I want to find the bugs I have not noticed yet". Different ergonomic preference; both have their audience.
One flat price, no API key
$9/mo for 1,000 AI calls including all features — no OpenAI key, no per-token billing, no top-up math. The trade-off is a ceiling at 1,000 calls; for typical Pro usage (50–200 calls/month) this is well below the ceiling.
Pricing — how to compare
SheetAI's tier names and prices change over time, and we want this comparison to stay honest rather than carry stale numbers. Live source-of-truth: sheetai.app/pricing. Their FAQ also lists separate Unlimited tier pricing details.
| Tier | SheetAI | SheetBrain |
|---|---|---|
| Free | Limited usage — see SheetAI pricing | 15 AI calls/mo + unlimited deterministic scans |
| Paid entry | See SheetAI pricing | $9/mo Pro (1,000 AI calls, all features, no API key) |
| Unlimited | BYO OpenAI key — see SheetAI pricing for current price | Not offered |
| Top-up packs | Token packs — see SheetAI pricing | Not offered (yet) |
SheetBrain at $9/mo includes the deterministic Check (Detector Set v0.4: broken references, visible formula errors, mixed types, duplicate lookup keys, formula pattern outliers, missing copied formulas) plus AI Generate / Explain / Debug / Repair. SheetAI's tiers cover a different surface: AI as a sheet-function primitive, plus image generation and text intelligence. Whether one is a better fit than the other depends entirely on what you need to do, not which is "cheaper" in the abstract.
Why someone might use both
SheetAI as the formula-primitive layer for column-wise text work (extract, classify, summarize). SheetBrain as the sidebar audit layer (Check + Repair) so the data those text functions are reading is structurally clean. Marketplace permissions for both are independent; they do not conflict.
Try SheetBrain free for 60 seconds
The deterministic Check tab is free, unlimited, and runs in the same sheet you already have open in SheetAI. Worth a real comparison.
Install free on Google Workspace