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Numerous.ai runs AI on your rows.Formula Foundry writes the formulas behind them.

Formula Foundry

Formula editor & manager

NA

Numerous.ai

ChatGPT in a spreadsheet cell

Numerous.ai is best known for one clever idea: an =AI() function you drag down a column to run ChatGPT across thousands of rows — categorize, extract, summarize, generate text — no API keys. Formula Foundry is a different tool: an AI formula IDE for Excel and Google Sheets that writes real spreadsheet formulas from plain English, fixes and explains them, and lets you save and reuse them. Plus a free in-browser playground.

Try Formula Foundry freeSee pricing

Free plan · No credit card · Your data stays in your sheet

The context worth knowing

Numerous.ai earned its niche with a genuinely useful trick — calling an AI model from inside a cell so you can apply it to data at scale without leaving the sheet or touching an API key. It also generates formulas, but its center of gravity is running AI over rows of data. Formula Foundry's center of gravity is the formula itself: a real multi-line editor, plain-English generation, debugging and explanation, global variables, and a reusable snippet library across Excel and Google Sheets.

If you're choosing between them, the question is whether you want AI to process your data row by row, or a workspace to write and maintain the formula logic that runs your model.

Side-by-side at a glance

Both touch AI and spreadsheets — but they're aimed at two different jobs. Here's the split.

Primary use case

Formula Foundry
AI formula IDE — write, fix, reuse
NANumerous.ai
AI-in-a-cell for bulk data

Where it runs

Formula Foundry
Excel + Google Sheets + browser playground
NANumerous.ai
Google Sheets + Excel

AI formula generation (plain English)

Formula Foundry
NANumerous.ai

Multi-line formula editor

Formula Foundry
NANumerous.ai

Fix / debug / explain a formula

Formula Foundry

In-editor AI

NANumerous.ai

Save & reuse formulas as snippets

Formula Foundry
NANumerous.ai

@@Global variables

Formula Foundry
NANumerous.ai

Bulk AI across thousands of rows

Formula Foundry
NANumerous.ai

=AI() function

AI text generation / enrichment in-cell

Formula Foundry
NANumerous.ai

AI web lookups / research in-cell

Formula Foundry
NANumerous.ai

Free in-browser playground

Formula Foundry
NANumerous.ai

Flat pricing (no token/character metering)

Formula Foundry
NANumerous.ai

Metered by characters

Shared team snippet library

Formula Foundry

Pro & Business

NANumerous.ai

Permanent free plan

Formula Foundry

~20 AI gens/mo

NANumerous.ai

$1 7-day trial

Pricing model

Formula Foundry
Free plan + subscription
NANumerous.ai
Subscription only

Starting price (paid)

Formula Foundry
Free; Pro $19/mo

$15/mo billed annually · Business $29/seat

NANumerous.ai
From $10/mo

Annual billing · no free plan

Prices and feature parity verified June 2026 from Numerous.ai's public pricing page. Send corrections to support@formulafoundry.io.

Where Formula Foundry wins

Built for formulas you own, not AI output you rent

Numerous.ai's =AI() returns a model's answer into a cell. Formula Foundry returns a native formula you can read, debug, reuse, and trust to recalculate on its own.

Real formulas, not live AI calls

Formula Foundry writes native spreadsheet formulas — INDEX/MATCH, QUERY, ARRAYFORMULA — that you own and that recalculate with no model in the loop. Numerous.ai's =AI() is an AI call that runs (and meters) every time it recalculates. For logic you depend on, a deterministic formula beats a rented answer.

@@Variables — change one value, update 500 formulas

Define @@DiscountRate, @@HeadcountTarget, @@FXRate once and reuse them across every formula in your workbook. Update one value, and every dependent formula follows. Numerous.ai processes rows of data; it doesn't manage reusable formula logic across a model.

A real editor — and a debugger

Multi-line, syntax-highlighted, bracket-matched, with AI that explains and fixes what's there. When a formula returns #N/A at 3pm on a Friday, you can read it and find the bug. Numerous.ai gives you a cell that says what the model returned — not a place to understand or repair the formula.

Flat pricing and a free plan that never expires

Numerous.ai meters usage by characters and has no permanent free tier — just a $1 seven-day trial. Formula Foundry is free to start forever, with flat Pro at $19/month ($15/month billed annually) and Business at $29/seat/month ($24/seat annually). No token math, no countdown.

Where Numerous.ai wins

When Numerous.ai is the better choice

Numerous.ai does something Formula Foundry deliberately doesn't. Here's when it's the right tool over us.

  • You need to run AI across thousands of rows. Drag =AI() down a column and categorize, extract, summarize, or translate at scale. Bulk AI-on-data is Numerous.ai's whole reason to exist, and Formula Foundry doesn't do it.

  • You want AI as a live spreadsheet function, no API keys. The =AI() function recalculates like any formula and handles the model plumbing for you. For AI-in-a-cell workflows, that convenience is genuinely nice.

  • Your job is generating data, not formulas. Writing product descriptions, drafting outreach copy, enriching a list — if AI *content* is the deliverable, that's Numerous.ai's lane, not Formula Foundry's.

  • You want built-in helpers for common LLM tasks. Sentiment tagging, classification, extraction, and similar templates come ready to apply to a range. If those are your daily tasks, it's purpose-built for them.

We’d rather you pick Numerous.ai for the right reason than Formula Foundry for the wrong one.

Best fit

Formula Foundry is built for you if…

  • You write and maintain real spreadsheet formulas in Excel, Google Sheets, or both
  • You want plain-English formula generation plus fix, debug, and explain
  • You want global variables that update every formula referencing them
  • You reuse logic across a model and want a saved, shareable snippet library
  • You want predictable flat pricing, not per-character metering
  • You want a free plan that never expires — and a playground to try first
Getting started

Try Formula Foundry alongside Numerous.ai

  1. Start in the playground

    Open the free in-browser playground and generate a formula from plain English — no install, no account, no credit card. See the formula workflow before touching your spreadsheet.

  2. Install the add-in

    Add Formula Foundry from the Google Workspace Marketplace or Microsoft Marketplace. It lives in the sidebar next to your sheet, and it doesn't conflict with Numerous.ai if you keep both.

  3. Free to start

    The free plan never expires — around 20 AI generations a month, the full editor, and your personal snippet library. Upgrade to Pro whenever you need more.

Get started free

Got questions?

FAQs

The AI that writes formulas
you actually own.

Numerous.ai is great when you want AI to chew through rows of data. When you want to write the formula, understand it, fix it, and reuse it — across Excel and Google Sheets — Formula Foundry is the workspace built for that job.

Pick your platform

Workspace add-on

Google Sheets

Turn Google Sheets into a maintainable formula environment.

  • Multi-line editor with @@variables
  • Excel-to-Sheets translator built in
  • Snippets sync across your team
Install on Google Sheets

Opens Google Workspace Marketplace

Excel for the Web add-in

Microsoft Excel

Reuse logic across workbooks — without rebuilding the same formulas.

  • Multi-line editor with @@variables
  • Works in Excel for the Web
  • Same library, both surfaces
Install on Excel

Opens Microsoft Marketplace

See pricing

Free plan · No credit card required · Your data never leaves your spreadsheet

See how Formula Foundry stacks up

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