A True Side-by-Side Calculator for iPhone & iPad

Why one calculator is never enough

Every phone calculator has the same blind spot: it holds exactly one number. Compare two prices and you're memorizing the first result while typing the second. Check your work and you destroy the original. The workaround everyone uses — jotting intermediate results into Notes — is exactly the problem a side-by-side calculator removes.

CalcBoard opens with two independent panels ready to go. Type 24.99 × 3 in the left panel, 26.50 × 3 − 5 in the right, and both results sit on screen together. Nothing to memorize, nothing to clear.

Independent panels, shared results

• Each panel is a complete calculator. Its own expression, its own result, its own undo/redo — clearing one never touches another.
• Different modes per panel. Run basic arithmetic on the left and a unit converter on the right, or scientific next to programmer (modes beyond basic are part of Premium).
• Shared value tray (Premium). Push a result from one panel and pull it into any other — the tray holds up to 50 values, each tagged with its source panel.
• Named variables. Type tax=0.0825 once and use price*tax in any panel, in any mode. Variables persist between sessions.
• Built-in layouts. Quick-launch presets set up common pairs instantly: Price Comparison and Homework Helper are free; Engineering and Developer come with Premium.

Made for how you actually compare

Comparing two loan offers? Put each scenario in its own panel and change one number at a time. Grading homework? Keep the answer key calculation open while you re-run each problem. Cooking from a doubled recipe? One panel scales quantities while another converts units. The point of side-by-side isn't novelty — it's that both numbers stay visible while you think.

Results are exact, too: CalcBoard computes with decimal arithmetic rather than floating point, so 0.1 + 0.2 is exactly 0.3 — which matters when the two numbers you're comparing differ by pennies.

Frequently Asked Questions