Calculation methodology

We parse clock values into integer seconds. Duration calculations subtract start from end, apply an explicit day boundary or date difference, and subtract a validated break.

Time arithmetic sums signed integer seconds. Decimal conversion uses hours + minutes ÷ 60 + seconds ÷ 3,600. Reverse conversion returns through integer seconds to avoid floating-point display artifacts.

The launch calculator uses local wall-clock values. It does not apply named time zones or daylight-saving transitions. See the detailed project methodology for edge cases and rounding.