Every calculator runs in your browser: no signup, and nothing you type is stored. Each one answers a single question the Flags app tracks continuously.
Run the weighted US 183-day math with exempt student and teacher years handled, worked out step by step.
The full three-part SRT on one page, with a ties checklist that moves your day ceiling as you tick.
Count your 330 full days abroad in any 12-month window — and find the window that qualifies.