Numi
Calculator and converter application
Numi — Official Website
Quick Take: Numi
Numi does one thing exceptionally well: it makes calculations feel like writing. The natural language input, mixed text-and-math documents, and variable support create a tool that's genuinely faster than a traditional calculator for anything beyond simple arithmetic. Freelancers writing project estimates, developers doing unit conversions, and anyone who keeps calculation notes will find Numi fits naturally into their workflow. The free tier is generous—the $30 upgrade is only necessary for sync and multiple documents. The 4.5 rating reflects a mature, focused tool that's earned its 6,300+ GitHub stars.
Best For
- •Freelancers and consultants who write project estimates with calculations
- •Developers who do frequent unit and data size conversions
- •Anyone who mixes notes and math in the same document
What is Numi?
Numi is a text-based calculator for macOS that lets you type math in plain English alongside notes. Instead of punching numbers into a calculator grid, you type expressions like '15 hours * $75/hour + 10% tax' or '200 EUR in USD' directly into a text editor. Numi interprets the math, converts the units, and shows results inline. The best way to understand Numi is to compare it to how you actually do calculations on paper. When you're estimating a project cost, you don't write '15 * 75 * 1.1' — you write 'Design phase: 15 hours at $75/hour plus 10% tax.' Numi works the same way. You type the description and the math together, and Numi figures out which parts are calculations. The result appears on the right side of each line. This text-first approach turns Numi into something between a calculator and a scratchpad. A freelancer quoting a project types the breakdown in plain language and gets the total. A developer converting API response sizes types '2.5 MB in KB' and sees 2560. A traveler planning expenses types '150 EUR + 200 GBP in USD' and gets a combined total with current exchange rates. Numi handles unit conversions (length, weight, temperature, data, time), currency conversions with live exchange rates, time zone calculations, percentage operations, and basic programming operations (hex, binary, CSS colors). You can define variables—'hourlyRate = 85'—and reference them later: '40 hours * hourlyRate.' This makes Numi useful for repeated calculations that share values. The interface is minimal: a text area on the left, results on the right. No buttons, no menus cluttering the workspace, no calculator grid. It looks like a code editor for math. Lines that don't contain math are treated as comments—so you write notes, headings, and context alongside calculations. The whole document becomes a self-explanatory calculation sheet. Numi was created by Dmitry Nikolaev in 2015 and has built a steady following among developers, freelancers, and anyone who finds traditional calculators tedious. The project is open-source with 6,300+ GitHub stars. The macOS app is free with a $30 paid upgrade for iCloud sync and multiple documents. It's also available through Setapp.
Install with Homebrew
brew install --cask numiDeep Dive: Text-Based Calculators and Why They Work
How moving calculations from grids to text editors changes the way people think about math.
History & Background
The idea of typing math as text rather than clicking calculator buttons has been around since command-line tools like bc and dc in Unix (1975). But those tools required strict syntax. Numi, launched in 2015 by Dmitry Nikolaev, brought natural language parsing to the concept—you type '20% of $150' instead of '150 * 0.2.' Soulver (2005) pioneered the category with a similar approach. What both tools recognized is that people think about math in words and sentences, not in calculator syntax. The text-based calculator category remains small but has loyal users who find the approach fundamentally better for everyday math.
How It Works
Numi uses a custom parser that tokenizes each line of text, identifies mathematical expressions, operators, units, and currencies, and evaluates them. Non-mathematical text is ignored (treated as comments). Variables are stored in a symbol table that's shared across the document. The parser handles ambiguity through precedence rules—'5 feet in meters' is recognized as a unit conversion, not '5 feet' times 'in' times 'meters.' Currency rates are fetched from external APIs on launch and cached. The macOS app is built natively with Swift, while the CLI version is a separate implementation.
Ecosystem & Integrations
Numi's ecosystem includes the macOS desktop app (primary), a CLI version (numi-cli) for terminal and scripting use, and an Alfred workflow for launcher integration. The open-source repository on GitHub accepts community contributions—users have added units, fixed parsing edge cases, and improved localization. The CLI version is useful for automation: pipe calculations through numi-cli in shell scripts or CI pipelines. Soulver, the main competitor, has a broader ecosystem with iOS apps, Shortcuts integration, and more structured document features.
Future Development
As a mature open-source project, Numi's development pace has slowed from its early years, but the community continues contributing fixes and improvements. The CLI version received updates in late 2025. Potential improvements include better support for multi-line expressions, integration with macOS Shortcuts, improved currency rate sources, and dark mode refinements. The text-based calculator concept itself is stable—Numi's core value proposition hasn't changed since 2015 and doesn't need to.
Key Features
Natural Language Math
Type calculations in plain English: '20% of $150,' '5 miles in km,' 'half of 248.' Numi's parser identifies mathematical expressions within natural text and computes results. You don't need special syntax or function names—write math the way you'd write it on a whiteboard. Support includes basic arithmetic, percentages, powers, roots, and trigonometric functions.
Unit Conversions
Convert between hundreds of units by typing conversions naturally: '72°F in Celsius,' '5 kg in pounds,' '2 TB in GB,' '90 minutes in hours.' Numi covers length, weight, volume, temperature, data storage, time, speed, and area. Conversions happen inline—type the expression and the result appears immediately.
Live Currency Conversion
Convert between currencies with rates that update automatically: '500 USD in EUR,' '1200 JPY in GBP,' '150 EUR + 200 CHF in USD.' Numi pulls current exchange rates and applies them to your calculations. For freelancers billing international clients or travelers budgeting trips, currency conversion that works inside your calculation notes saves constant tab-switching to Google.
Variables and References
Define variables and use them across your document: 'hourlyRate = 85' on line 1, 'design: 20 hours * hourlyRate' on line 5, 'development: 40 hours * hourlyRate' on line 6. When you change hourlyRate, all references update automatically. This turns Numi into a lightweight spreadsheet for back-of-envelope calculations—without the overhead of actually opening a spreadsheet.
Time Zone Calculations
Calculate time differences and convert between zones: 'now in Tokyo,' '3pm EST in PST,' '9:30am London in New York.' For remote teams scheduling meetings or developers coordinating deployments across time zones, typing the conversion directly into a calculation sheet is faster than opening a separate time zone converter.
Mixed Text and Math
Write notes alongside calculations. Lines without math are treated as plain text—use them for headings, descriptions, context, or explanations. A project estimate becomes a readable document: 'Project: Website Redesign' followed by itemized calculations with descriptions. When someone reads your estimate, they see both the reasoning and the numbers.
Global Shortcut & Alfred Integration
Summon Numi instantly from any app with a configurable global keyboard shortcut. Type a quick calculation, see the result, and go back to work. The Alfred workflow lets you type calculations directly in Alfred's search bar ('numi 15% of 230') and see the result without even opening Numi's window.
CSS Color Conversions
Convert between color formats: '#FF5733 in rgb,' 'rgb(100, 200, 50) in hex.' For front-end developers who switch between hex, RGB, and HSL color values regularly, having color conversion in the same tool as other calculations is a minor but genuine convenience.
Who Should Use Numi?
1Freelancer Estimating Projects
A freelance designer needs to quote a multi-phase project for an international client. In Numi, they type: 'Research: 8 hours * $85/hour,' 'Design: 20 hours * $85/hour,' 'Revisions: 10 hours * $85/hour,' then 'Subtotal: research + design + revisions' followed by 'Total in EUR: subtotal in EUR.' The quote is a readable document with clear line items. When the client asks for a 10% discount, the designer adds 'Discount: 10% of subtotal' and 'Final: subtotal - discount in EUR.' Done in 30 seconds.
2Developer Doing Quick Conversions
A developer is debugging a file upload issue. The API returns a 413 error for files over a certain size. They open Numi and type: 'maxSize = 10 MB in bytes' to get the byte limit, '15.5 MB in bytes' to check the failing file size, and '15.5 MB - 10 MB' to see how much over the limit the file is. The entire investigation happens in a text editor, not a browser.
3Remote Team Coordinator
A project manager coordinates a team across San Francisco, London, and Tokyo. They need to find a meeting time that works for everyone. In Numi: '10am PST in London' shows 6pm GMT, '10am PST in Tokyo' shows 3am JST (too late). They try '8am PST in Tokyo' — 1am JST (still bad). '5pm London in Tokyo' — 2am JST. They see there's no perfect time and decide on async updates for Tokyo.
How to Install Numi on Mac
Numi is available through Homebrew and the Mac App Store.
Install via Homebrew
Run `brew install --cask numi`. The app installs to your Applications folder.
Launch Numi
Open Numi from Applications or Spotlight. You'll see a clean text area—start typing calculations immediately.
Set Up Global Shortcut
Go to Numi > Preferences > General and configure a global keyboard shortcut (e.g., Option+Space). This lets you summon Numi from any app for quick calculations.
Optional: Alfred Workflow
If you use Alfred, install the Numi Alfred workflow from the Numi website. This lets you run calculations directly from Alfred without opening Numi's window.
Pro Tips
- • Start by typing a simple calculation: '15% of 230' or '100 USD in EUR.' See how the result appears on the right side of the line.
- • Use blank lines and text-only lines as section headers. Numi ignores non-math lines, so you can organize calculations with headings.
- • Define variables at the top of your document for values you reference multiple times: 'rate = 85' then use 'rate' anywhere below.
Configuration Tips
Create Template Documents
If you regularly make the same type of calculation (weekly invoicing, travel budgets, project estimates), create a template document with your standard variables and structure. Duplicate it for each new calculation. The template keeps your format consistent and saves setup time.
Use Numi as a Unit Conversion Scratchpad
Keep Numi running and use the global shortcut whenever you need a quick conversion. '72°F in C' during a weather discussion. '2.5 liters in cups' while cooking. '500 GB in TB' while shopping for drives. The shortcut makes Numi faster than opening Google for conversions.
Alternatives to Numi
Text-based calculators are a small but interesting category with a few strong options.
Soulver
Soulver ($34.99) is Numi's closest competitor—a text-based calculator with natural language support, variables, and unit conversions. Soulver has more structured syntax, better spreadsheet-like features (sheets, totals, stocks), and a more polished interface. Numi's advantage is being open-source with a free tier. If you want the best text-based calculator regardless of price, Soulver edges ahead on features. If you want free or open-source, Numi wins.
Raycast Calculator
Raycast includes a built-in calculator that handles basic math and unit conversions from the launcher. It's faster for one-off calculations ('15% of 200') but lacks Numi's multi-line documents, variables, and currency conversions. Use Raycast for quick math, Numi for calculation documents.
Spotlight Calculator
macOS Spotlight can do basic arithmetic—type '15 * 23' and see the result. It handles simple unit conversions too. But it's one expression at a time, no variables, no document, no currency. It's the baseline that tools like Numi improve upon.
Pricing
The free version is fully functional for single-document calculations. The paid version ($30 one-time, covers two devices) adds iCloud sync across Apple devices and multiple document support. Also available through Setapp subscription.
Pros
- ✓Natural language input removes the friction of calculator interfaces
- ✓Mixed text and math creates self-documenting calculation sheets
- ✓Live currency conversion with current exchange rates
- ✓Variables make repeated calculations easy to update
- ✓Global shortcut provides instant access from any app
- ✓Open-source with active community (6,300+ GitHub stars)
- ✓Available on macOS, Windows, Linux, and as a CLI tool
- ✓Clean, distraction-free interface
- ✓One-time $30 purchase — no subscription for the paid tier
Cons
- ✗iCloud sync and multiple documents require the $30 paid version
- ✗$30 is steep compared to free alternatives for basic calculations
- ✗Learning natural language syntax takes experimentation—some expressions parse unexpectedly
- ✗No graphing or visualization capabilities
- ✗Currency rates may lag behind real-time market rates
- ✗Not a replacement for a full spreadsheet—no cell references, no formulas across sheets
Community & Support
Numi is an open-source project created by Dmitry Nikolaev, hosted on GitHub with 6,300+ stars and 247+ forks. The repository accepts community contributions—users have contributed localization, additional unit support, and bug fixes. Discussion happens on GitHub Issues, Reddit (r/macapps), and the broader macOS productivity community. The CLI version (numi-cli) is maintained separately and supports scripting and automation workflows. An Alfred workflow is maintained for launcher integration.
Video Tutorials
Getting Started with Numi
More Tutorials
Numi | The Smartest Calculator for Mac?
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Frequently Asked Questions about Numi
Our Verdict
Numi does one thing exceptionally well: it makes calculations feel like writing. The natural language input, mixed text-and-math documents, and variable support create a tool that's genuinely faster than a traditional calculator for anything beyond simple arithmetic. Freelancers writing project estimates, developers doing unit conversions, and anyone who keeps calculation notes will find Numi fits naturally into their workflow. The free tier is generous—the $30 upgrade is only necessary for sync and multiple documents. The 4.5 rating reflects a mature, focused tool that's earned its 6,300+ GitHub stars.
About the Author
Productivity & Workflow Analyst
Related Technologies & Concepts
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Sources & References
Fact-CheckedLast verified: Feb 23, 2026
- 1Numi - Beautiful Calculator for Mac
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- 2Numi GitHub Repository
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