Grid Reference UK - OSGB36

Surveyor.DEV

About this app

🗺️ UK Grid Tools – Grid Reference Finder, Postcode Finder & Coordinate Converter
The most accurate way to convert GPS coordinates into British National Grid References, OSGB36, and UK Postcodes — online and offline.

📍 WHAT IT DOES
UK Grid Tools is a free, professional-grade app that helps you convert your current location (GPS / WGS84 / ETRS89) into:

- 📌 British National Grid Reference
- 📌 OSGB36 (15) coordinates
- 📌 UK Postcode (powered by postcodes.io + offline fallback)
- 📌 Shareable location formats for maps and messaging

Designed for surveyors, engineers, outdoor enthusiasts, GIS professionals, and anyone needing accurate UK location data — the app ensures your coordinates are within 1 metre of accuracy.

🧠 WHY IT’S ACCURATE
Most apps rely on an outdated 7-parameter Helmert transformation, which can introduce errors of 3–10m or more across Great Britain.

UK Grid Tools uses the Ordnance Survey OSTN15 transformation model via a 20km grid implementation to achieve:

- ✅ <0.15m horizontal accuracy in 95% of the UK

- ✅ Fully compliant OSGB36(15) values

- ✅ True 10-figure Grid Reference precision

This makes it the most accurate grid reference finder available on Android today.

📫 POSTCODE FINDER (HYBRID ONLINE & OFFLINE)
We use the postcodes.io API to instantly retrieve your UK postcode from your GPS location. If you're offline, the app automatically uses a local fallback geocoder (where available) to still show a postcode — making it great for use in the field.

🌟 TOP FEATURES

✅ Convert GPS to Grid Reference, OSGB36, and Postcode
✅ Highly accurate coordinate transformation with OSTN15
✅ View coordinates in multiple formats
✅ Works both online and offline
✅ Uses postcodes.io for postcode lookup
✅ Offline fallback geocoder when no internet is available
✅ Customise the grid reference output (figures & separators)
✅ Customise WGS84 display: DMS / DM / DD, signs or quadrants
✅ Share your location via SMS, messaging apps, or clipboard
✅ Open current location in maps with one tap
✅ Tap & hold to copy values
✅ Built-in GPS accuracy display
✅ Manual coordinate input (Grid Ref, Easting/Northing, WGS84)
✅ Card visibility settings – show only the details you care about
✅ Light, dark, or system theme

📱 DESIGNED FOR FIELD USE

- Extremely lightweight app (under 10MB)
- No ads, no tracking
- Works indoors, outdoors, or with partial signal
- Great for geocaching, hiking, planning, surveying, field work

🚀 VERSION 2.1 – WHAT’S NEW

📮 Postcode card added (auto + fallback)

🧩 Card visibility settings to declutter the interface

🧪 Performance improvements & accuracy tweaks

✅ Full Material 3 UI refresh

🆓 Still 100% free, with no ads and no login

UK Grid Tools is ideal for anyone needing a reliable grid reference finder, accurate postcode lookup, or high-precision coordinate transformation between WGS84, OSGB36, and British National Grid References. Easily share location within a standard SMS size.

If you’re looking for the most accurate UK Grid Reference app, with built-in postcode lookup and robust coordinate transformation, UK Grid Tools is the one to download.

What’s new

New features:

App now shows Postcode (UK only)
Card visibility added
Further configurations for WGS84 coordinates (show letter at the beginning or the end)
Reduced shared coordinates text size to fit a standard SMS (160 characters).
Other bug fixes and QoL improvements.