Lens Prescription Conversion Tool

• Lens prescription conversion tool with four modes: frame glasses ↔ contact lenses, astigmatism spherical-equivalent, and base curve reference
• Based on the vertex distance formula, automatic precise conversion for prescriptions over 400°; for dispensing reference

1. Open the tool page — no installation needed; it starts in Frame → Contact mode
2. Switch modes at the top and choose the left/right eye powers (or click "Load Example" to fill in sample data)
3. Click "Calculate" to get the result, then click "Copy Result" in the result area to copy it

• This tool is completely free and requires no sign-up
• All calculations run locally in your browser — your data never leaves your device

Free online lens prescription conversion tool supporting frame glasses to contact lenses conversion, astigmatism conversion, and base curve reference. Based on vertex distance formula, automatic precise conversion for prescriptions over 400 degrees.

Open the tool page — no installation needed; it starts in Frame → Contact mode Switch modes at the top and choose the left/right eye powers (or click "Load Example" to fill in sample data) Click "Calculate" to get the result, then click "Copy Result" in the result area to copy it

This tool is completely free and requires no sign-up All calculations run locally in your browser — your data never leaves your device

Yes, Lens Prescription Conversion Tool is completely free. No download or installation required — it runs right in your browser.