Eyewear & Optics Calculators
Free, practical tools for glasses and contact-lens wearers — measure your PD, convert a prescription between glasses and contacts, size a frame, estimate lens thickness, decode a sunglass tint, and budget the cost of your lenses.
Pupillary Distance (PD) Calculator
Combine per-eye PD into a binocular total, split a binocular PD into halves, and work out your near reading PD — the measurement that centres every lens on your eyes.
Vertex Distance Power Converter
Convert a prescription between glasses and contacts with the vertex-distance formula, and see the exact and nearest-0.25 D power — the correction that matters in strong prescriptions.
Frame Size & Fit Calculator
Turn the eye-size, bridge, and temple numbers plus your PD into a fit estimate: frame PD, lens span, decentration, and whether a frame runs wide or narrow.
Lens Thickness Estimator
See how sphere power, material index, and frame size drive lens thickness — and how much a higher index or a smaller frame actually slims a strong prescription.
Sunglass Tint & UV Category Finder
Turn a lens's light-transmission percentage into its filter category 0–4, with darkness, driving suitability by day and night, and where each tint belongs.
Contact Lens Cost-per-Wear Calculator
Find the real running cost of contacts — annual spend and cost per day worn — and compare daily disposables against monthlies on your own wear schedule.