Available free on iPhone & iPad · No ads · No account needed

Multiple Calculators.
One Screen.

CalcBoard is the multi-panel calculator app for iPhone and iPad. Run up to 8 independent calculators side by side, share values between panels, and switch between basic, scientific, programmer, and unit converter modes — all on one screen. No mainstream calculator app does this.

0
Ads. Ever.
4
Calculator modes
8
Simultaneous panels
79
Units to convert
$2.99
One-time unlock. Forever.

Why CalcBoard Replaces Your Default Calculator

Multiple independent calculator panels running simultaneously, with shared state between them — something no mainstream calculator app offers. Stop switching between apps. Stop losing your place.

Multi-Panel Calculator Layout

Open up to 8 independent calculators at once. Each panel runs its own mode, history, and state. Compare prices, run scenarios, or solve homework problems — all in parallel without switching screens.

Shared Value Tray

Push a result from one panel to the shared tray and pull it into another. Transfer values between calculators instantly — no copying, no retyping, no lost numbers.

Named Variables

Save any value as a variable — type tax=0.0825 once, then use price*tax in any panel. Variables persist between sessions and work across every calculator mode.

Four Calculator Modes

Basic, scientific, programmer, and unit converter. Each panel picks its own mode independently. One app handles every type of calculation — from simple arithmetic to binary-to-hex conversion.

Full Calculation History

Every result is saved automatically. Bookmark important calculations and add custom labels; Premium unlocks your full history with search and CSV export. Never lose a calculation again.

Precise Decimal Arithmetic

Arbitrary-precision math with no floating-point rounding errors. 0.1 + 0.2 = 0.3 exactly, every time. Financial calculations, engineering formulas, and scientific computations you can trust.

Unit Converter (79 Units)

Instant conversion across 10 categories: length, mass, temperature, area, speed, time, data size, volume, energy, and pressure. Type a value and see the result instantly.

Control Center Quick Launch

Add CalcBoard to your iPhone's Control Center and launch it in a single tap from any screen. Faster than opening the app drawer.

Fully Customizable

8 color themes, 6 button styles (Classic, Glass, Circle, Edge-to-Edge, Soft, Minimal), light and dark mode, haptic and sound feedback. Make CalcBoard look and feel exactly how you want.

Built for Accessibility

VoiceOver labels on every key, WCAG AA contrast ratios, 48px minimum touch targets, and reduce-motion support. Designed for everyone from the start.

Four Calculator Modes. One App.

Set each panel to its own mode. Basic math in one, scientific in another, programmer in a third, unit converter in a fourth — all running simultaneously.

Free

Basic Calculator

Standard arithmetic with full algebraic expression editing and arbitrary-precision results.

  • Add, subtract, multiply, divide with correct order of operations
  • Parentheses for complex expressions
  • Casio-style percentage calculations (100+10% = 110)
  • Undo, redo, and inline cursor editing
Premium

Scientific Calculator

Trigonometric, logarithmic, and exponential functions for students, engineers, and scientists.

  • sin, cos, tan and inverse functions
  • ln, log, e^x, 10^x
  • Square root, cube root, factorial
  • Constants: pi (π) and Euler's number (e)
Premium

Programmer Calculator

Binary, octal, decimal, and hexadecimal with bitwise operations for developers.

  • BIN, OCT, DEC, HEX input and simultaneous display
  • Bitwise AND, OR, XOR, NOT
  • Left shift (<<) and right shift (>>)
  • Hex digits A-F with full keyboard
Free (basic) / Premium (full)

Unit Converter

Instant conversion across 10 categories with 79 units. Results appear as you type.

  • Free: Length, mass, temperature
  • Premium: Area, speed, time, data, volume, energy, pressure
  • 79 units across all categories
  • Instant bidirectional conversion

See CalcBoard in Action

Real screenshots from the shipping app — multi-panel layouts, every calculator mode, and themes on iPhone and iPad.

CalcBoard on iPhone running two calculator panels at once in the dark Coral theme
Two panels side by side
CalcBoard scientific calculator mode on iPhone showing sin, cos, tan, ln, and log keys in the light CalcBoard Blue theme
Scientific mode
CalcBoard programmer calculator on iPhone displaying a value in binary, octal, decimal, and hexadecimal simultaneously
Programmer mode: 4 bases at once
CalcBoard unit converter on iPhone converting temperature in the light Amber theme
Unit converter
CalcBoard basic calculator on iPhone in the dark Lavender theme with edge-to-edge buttons
8 themes × 6 button styles
CalcBoard on iPad running multiple calculator panels in a landscape grid layout
Multi-panel grid on iPad

Start Calculating in Seconds

No account. No setup. No tutorial required. Open CalcBoard and you're already calculating.

Open CalcBoard

Two calculator panels are ready immediately. Start calculating with zero setup.

Choose Your Modes

Set each panel to Basic, Scientific, Programmer, or Unit Converter independently.

Calculate in Parallel

Work on multiple calculations at once. Each panel maintains its own independent state.

Share Results

Push values to the shared tray and pull them into any panel with a single tap.

Stop Juggling One Calculation at a Time

Standard calculator apps force you to do one calculation, write it down, clear, and start another. CalcBoard keeps everything visible at once.

Price Comparison

Two stores, two panels, instant side-by-side comparison

Homework Help

Multiple math problems visible and solvable simultaneously

Engineering

Convert units in one panel while calculating in another

Finance

Compare loan scenarios, budgets, or investments side by side

Software Development

Hex, binary, octal, and decimal conversions alongside math

Construction

Materials, measurements, and cost estimates all at once

How CalcBoard Compares to Other Calculator Apps

Mainstream calculator apps handle one calculation at a time. CalcBoard runs up to 8 panels at once with cross-panel value sharing.

Feature Apple Calculator PCalc ($9.99) Calzy ($2.99) CalcBoard (Free / $2.99)
Multiple simultaneous panels Up to 8
Shared value tray (cross-panel)
Scientific mode Landscape only
Programmer mode (BIN/OCT/HEX)
Unit converter Basic (iOS 18+) 79 units
Calculation history Basic (iOS 18+) Search, labels + CSV export
Arbitrary-precision decimals
Customizable themes 8 themes + 6 button styles
No ads
Price Free (built-in) $9.99 $2.99 Free / $2.99 one-time

Comparison verified August 2026 against each app's current App Store listing. Features and prices change — check the other apps' listings for their latest details.

No Subscriptions. No Ads. Ever.

Pay once, own it forever. CalcBoard will never show you an ad or charge a recurring fee. Your calculator shouldn't have a monthly bill.

One-Time Purchase

Premium Unlock

$2.99
Pay once. Yours forever. All future updates included.
  • Up to 8 simultaneous calculator panels
  • Shared value tray between panels
  • Scientific and programmer calculator modes
  • Full unit converter (10 categories, 79 units)
  • Unlimited calculation history with search & CSV export
  • 8 color themes & 6 button styles
Download CalcBoard Free

Generous Free Tier

2 panels, basic mode, 3 converter categories, last 10 history entries. No ads. No time limits. No catch.

FeatureFreePremium ($2.99)
Basic calculator with expression editing
Scientific calculator mode
Programmer calculator mode (BIN/OCT/DEC/HEX)
Unit converter (basic: length, mass, temperature)
Unit converter (full: 10 categories, 79 units)
Simultaneous calculator panelsUp to 2Up to 8
Shared value tray between panels
Calculation historyLast 10Full history + search
History export (CSV, copied to clipboard)
Color themes & button styles8 themes + 6 styles
AdsNoneNone

Frequently Asked Questions About CalcBoard

  • CalcBoard is a multi-panel calculator app for iPhone and iPad that lets you run up to 8 independent calculators on one screen simultaneously. Unlike the Apple Calculator or single-panel apps like Calzy, CalcBoard lets you see and work on multiple calculations at once, with a shared value tray to transfer results between panels. Each panel can run a different mode — basic, scientific, programmer, or unit converter.
  • CalcBoard is free to download and use with no ads. The free version includes basic calculator mode, 2 panels, 3 unit converter categories (length, mass, temperature), and the last 10 history entries. Premium is a one-time purchase of $2.99 — no subscriptions, no recurring charges. There are no ads in either version, ever.
  • Yes — that's exactly what CalcBoard is built for. You can run up to 8 independent calculator panels simultaneously on one screen. Each panel maintains its own calculation mode, state, and history. Free users get 2 panels; premium users get up to 8.
  • Yes. CalcBoard's scientific mode (premium) includes trigonometric functions (sin, cos, tan and inverses), logarithms (ln, log), exponential functions (e^x, 10^x), square root, cube root, factorial, and constants (pi, e). Unlike the Apple Calculator, which only shows scientific mode in landscape, CalcBoard's scientific mode works in any orientation and can run alongside other calculator panels.
  • Yes. CalcBoard's programmer mode (premium) supports binary (BIN), octal (OCT), decimal (DEC), and hexadecimal (HEX) input with all four bases displayed simultaneously. It includes bitwise AND, OR, XOR, NOT, and left/right bit shift operations. You can run programmer mode alongside basic or scientific panels to see decimal and hex results side by side.
  • With Premium, use the shared value tray. Long-press the active panel to open the panel menu, then tap "Push to tray." The current result appears in the shared value tray. Switch to another panel and tap any value in the tray to paste it into that panel's expression. The tray shows each value's source panel name and can store up to 50 values.
  • Open CalcBoard, go to Settings, then tap "Upgrade to Premium" and select "Restore Purchases." Make sure you're signed into the same Apple ID used for the original purchase. Your premium features will be restored immediately at no additional cost.
  • Yes. CalcBoard uses exact decimal arithmetic instead of the IEEE 754 floating-point math that causes rounding errors in most calculators. This means 0.1 + 0.2 = 0.3 exactly. Financial calculations, engineering formulas, and everyday math all produce precise results you can trust.

Don't Settle for a Single Calculator

Download CalcBoard free. No account needed. No ads. Premium is a one-time $2.99 unlock — yours forever.