A free, browser-based aviation mapping tool built for pilots, dispatchers, students, and anyone who wants to understand how aircraft get from A to B, and exactly how far they can go under real-world wind conditions.
Accurate wind modelling is the technical heart of Great Circle Pro. Range circles and flight time calculations use ERA5-derived 250 hPa jet-stream winds, the pressure level corresponding to roughly 34,000 ft where most long-haul jets cruise. Two percentile settings are available, each serving a different planning purpose:
Great Circle Pro applies the selected season's wind grid across 720 radial bearings. Winter, Summer, and Average are distinct upper-air wind models calibrated for each pattern, so the season button you click is the season that drives the math.
The wind speed exceeded only 15% of the time at that point on the grid. Great Circle Pro uses this as its conservative benchmark for ETOPS sensitivity analysis, because an OEI diversion should be tested against stronger-than-average headwinds rather than a median-wind display setting.
The seasonal average wind from a global ERA5 grid, what you'd expect on a typical day. Useful as a baseline for comparison against the 85th model, and for understanding typical block times rather than conservative planning figures.
Jeff S. is the creator and aviation enthusiast whose career spans hands-on flight operations, airline network planning strategy, and technology. He is an ex. corporate pilot on business aircraft, including variants of the Cessna Citation Jet and Beechcraft King Air. He later transitioned into corporate airline roles in International Network Planning & Strategy as well as Revenue Management. Jeff has also built numerous enterprise-level websites for large organizations. Today, he works as a management consultant for a global firm that began in the early 1800s. This tool was built as a hobby in his spare time to combine his operational flying background, airline network expertise, and technical skillset into a precise, practical mapping tool designed for aviation professionals and enthusiasts who demand greater insight into route planning and global connectivity.
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Great Circle Pro is for educational, planning, and analytical use only. Wind and fuel figures are estimates. Not certified for operational flight planning or dispatch use.
See the full feature list, learn how the great circle calculations work, explore the aircraft database, or read our guide to aircraft range circles. For common questions about great circle mapping, check the FAQ & glossary.