True-Wind Calculator

Sailing wind converter & log

Free · In‑App Purchases · Designed for iPad. Not verified for macOS.

New in 3.1 (Pro): live VMG and target boat speed from your polar, plus tack & layline tactics — when to tack and whether you can lay the mark. One-time unlock. The wind you feel on a moving boat isn't the real wind. True-Wind Calculator turns the apparent wind you measure into the true wind you need — in two taps, no wind instruments required. In use since 2013, completely rebuilt in 2026. HOW IT WORKS Enter boat speed, apparent wind speed, apparent wind angle and heading. The app does exact vector math — no lookup tables, no approximations — and gives you true wind speed and true wind direction instantly. Boat speed and heading can be filled automatically from GPS and compass with one tap. FREE • True wind speed, direction and angle — unlimited calculations • One-tap GPS fill for boat speed and heading • The formula explained, so you can trust the numbers • Works completely offline — no account, no ads, no tracking PRO (one-time purchase, no subscription) • Performance — live VMG, target boat speed, % of target VMG and point of sail, driven by your boat's polar • Tactics — tack preview, windward-mark laylines, and whether you can lay the mark • Boat polars — pick a preset or build your own in the editor • Compass rose view — heading, apparent and true wind on one dial • Calculation history — every result logged with its inputs • All speed units — knots, m/s, km/h, mph Bought the app back when it was paid? Pro is already yours — it unlocks automatically. PRIVACY Everything stays on your device. Location is read only to fill the input fields and never leaves your phone. No analytics, no third-party SDKs.

Ratings & Reviews

  • This app’s overall rating was recently reset.

v3.1 — Pro performance tools for serious sailors. • New: VMG and target boat speed, calculated against your polar curve (Pro) • New: tack & layline tactics — know exactly when to tack and whether you can lay the mark (Pro) • Pro remains a one-time unlock — no subscription, ever.

Version 3.1

The developer, Nejc Landeker, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer’s privacy policy .

  • Data Not Linked to You

    The following data may be collected but it is not linked to your identity:

    • Usage Data
    • Diagnostics

Privacy practices may vary, for example, based on the features you use or your age. Learn More

Accessibility

The developer has not yet indicated which accessibility features this app supports. Learn More

Information

Seller
  • Nejc Landeker
Size
  • 755.7 KB
Category
  • Navigation
Compatibility
Requires iOS 16.0 or later.
  • iPhone
    Requires iOS 16.0 or later.
  • iPad
    Requires iPadOS 16.0 or later.
  • Mac
    Requires macOS 13.0 or later and a Mac with Apple M1 chip or later.
  • Apple Vision
    Requires visionOS 1.0 or later.
Languages
English and 4 more
  • English, French, German, Italian, Slovenian
Age Rating
4+
In-App Purchases
Yes
Copyright
  • © Nejc Landeker
  • Developer Website
  • Privacy Policy

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