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Select currencies and enter an amount
ⓘ Rates from open.er-api.com · updated daily. Not for financial transactions.
Fill in any two fields — the third will be calculated.
Each sleep cycle is ~90 minutes. You should sleep for 5 or 6 complete cycles (7.5–9 hours).
More calculators
Frequently used tools move up top automatically.
Recent history
Saved on this device only. Passwords and QR contents are not saved.
No saved calculations yet.
What you can calculate
Free calculators by category
CalcHive brings everyday calculators for money, health, dates, travel, study and quick conversions into one lightweight tool.
Split Workspace drag and resize calculators
WiFi QR create a scan-to-join network code
Date tools age, date range, relationship, work hours and pregnancy
Keyboard ready number keys work on the active calculator
40+ tools money, health, travel, study and utilities
Split Workspace drag and resize calculators
WiFi QR create a scan-to-join network code
Date tools age, date range, relationship, work hours and pregnancy
Keyboard ready number keys work on the active calculator
40+ tools money, health, travel, study and utilities
Split View for side-by-side calculators
Workspace mode with draggable panels
Keyboard input for active calculator
Dark and light mode
Installable PWA
Latest additions
Updated 28 May 2026
28 May 2026
Local History
Recent results are saved on this device only, with copy, clear and reopen-tool controls.
28 May 2026
Mobile Header
Logo, site badge, split and theme controls now stay together in a compact mobile row.
28 May 2026
Key Feedback
Calculator keys now blink twice with a softer final glow when pressed.
27 May 2026
Split Workspace
Drag and resize calculator panels inside a full-window workspace.
27 May 2026
More Date Tools
Pregnancy, ovulation, period, relationship and work-hours calculators added.
27 May 2026
New Utility Tools
WiFi QR, QR code, password, word count, random number and unit tools are grouped for quick access.
27 May 2026
Keyboard Calculator
Number keys, operators, Enter, Escape and Backspace work on the active calculator.