Math at the speed of thought.
Notes Calculator turns plain-text notes into a powerful calculator. Variables, 200+ currencies, unit conversion — all answered instantly as you type.
- macOS
- Windows
- Linux
- Web
Features
Everything a calculator should have done years ago
Powerful enough for spreadsheets-tier problems. Simple enough to feel like writing a note.
Instant answers
Write expressions on the left and watch results appear on the right in real time.
Variables
Name values once, reference them anywhere. Change one number and totals recompute instantly.
Natural percentages
Write 20% of 240 or 80 + 15% — Notes Calculator parses percentage operations the way you'd write them in a note.
200+ currencies
Mix dollars, euros, pounds, yen and crypto in the same expression — write 100 dollars in euro and get a live answer. Rates refresh every hour.
Units that just work
Length, mass, volume, temperature, time, data — convert anything inline.
Tabs for every project
Keep separate notes for budgets, invoices, trips, and quick math — rename and rearrange them. Free includes one tab; Lifetime unlocks unlimited.
Multi platform
Native apps for macOS, Windows, and Linux. Web app for everywhere else. iOS & Android coming soon.
Keyboard shortcuts
Stay on the keyboard. Every action is one chord away.
Dark & light themes
Pixel-perfect in both modes — and your eyes will thank you at midnight.
Sync across devices
Open the same note on your laptop, desktop, and browser. Changes follow you.
How it works
From blank page to answer in seconds
No formulas. No cells. No menus. Just write — and let the calculator keep up with you.
- 01
Open a fresh note
Launch Notes Calculator on any device. No accounts, no setup — just a blinking cursor.
- 02
Type math like you would write it
Mix numbers, units, and currencies. Use variables to name values and reference them anywhere.
- 03
Get answers as you type
Results appear instantly on the right. Reference variables, change one number, and watch totals update in real time.
Built for the way you work
One calculator. Every kind of math.
From freelance quotes to student homework, Notes Calculator adapts to whatever you're working on.
Freelancers
Estimate quotes, work out hourly rates, and check invoice totals before sending.
ExploreStudents
Solve homework with variables, calculate GPAs, and convert units without leaving your notes.
ExploreTravelers
Convert between 200+ currencies in real time. Plan trips with mixed-currency budgets.
ExploreDevelopers
Convert hex, decimal, binary, and bytes. Sketch out math next to your code.
ExploreBusiness owners
Track profit margins, model budgets, and forecast compound growth in plain English.
ExploreEveryday math
Tips, splits, percentages, and quick mental-math shortcuts — all in one place.
ExploreFrom the blog
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Notes Calculator is free to use, fast to learn, and ready in your browser. Upgrade later if you want sync and unlimited tabs.
Free forever plan · No credit card · Cross-platform