Glasses to contacts · Astigmatism

Toric Contact Lens Calculator

Convert your glasses SPH, CYL and axis to theoretical contact lens power. See clear results and the calculation behind them; lens fitting remains separate.

Convert Your Astigmatism Prescription

Use the values written on your glasses prescription.

An optical conversion, not a contact lens prescription. Product powers, base curve, diameter and on-eye rotation require a professional fitting.

Both meridians calculatedPlus or minus CYL accepted

Understand your result

How to Convert Glasses to Toric Contact Lens Power

Astigmatism has two principal powers. Convert both before working out the new cylinder; simply changing SPH is not enough.

Two powers, one prescription

F_contacts = F_glasses ÷ (1 − d × F_glasses)

Apply the formula to S and S + C. Distance d is in metres: 12 mm becomes 0.012 m. Subtract the first unrounded result from the second to obtain CYL.

WORKED EXAMPLE / 12 MM

−8.00 / −2.00 × 180° in glasses

First meridian: −8.00 D: -7.2993 D
Second meridian: −10.00 D: -8.9286 D
Raw CYL: second − first: -1.6293 D

THEORETICAL RESULT / 0.25 D DISPLAY-7.25 / -1.75 × 180°

Axis stays at 180° in this minus-cylinder example. Display rounding does not select an available lens product.

A positive CYL is first transposed into minus-cylinder notation; that also turns the written axis by 90°.

Method references: ACUVUE meridian calculations and CooperVision’s theoretical and product powers. For the reverse direction, use the contacts-to-glasses calculator.

Conversion and fitting are different

What Does a Toric Conversion Tell You?

An optical starting point

The result moves the two powers from the glasses plane to the corneal plane. It does not replace a current refraction or issue a prescription.

CYL is kept separate

The spherical equivalent calculator uses S + ½C, a different calculation. This tool does not absorb cylinder into sphere or decide that spherical lenses suit your eyes.

Fit and available powers

Brands offer different sphere, cylinder and axis steps. Lens rotation, material, base curve and diameter need assessment during a fitting.

If you are planning a budget

Toric Contact Lens Price Examples

These specific products illustrate lens-supply costs. Use your prescribed product’s quote in the annual cost calculator for your own budget.

U.S. retail examples · USD · checked 2026-10-02
Product & schedule	Lenses / box	Box price	Both eyes / year
Acuvue Oasys 1-Day for Astigmatism (90 pack)Daily toric · Warby Parker	90	$137.90	$1,379.0010 whole boxes
ACUVUE® Oasys for Astigmatism Contacts14-day toric · Warby Parker	6	$73.85	$738.5010 whole boxes
Biofinity® Toric ContactsMonthly toric · Warby Parker	6	$75.85	$303.404 whole boxes

Regular prices before promotions, not national averages or product recommendations. Annual examples assume separate stock for both eyes, no starting stock, and 365 daily, 12 monthly or 27 two-week lenses per eye. Unused lenses are included in the purchase cost. Solution, tax, exams, fitting and insurance are excluded. Verify your prescribed product and checkout price.

Quick answers

Toric Contact Lens Calculator Questions

Can you wear contacts with astigmatism?

Toric contact lenses are designed to correct astigmatism. Which product and powers suit your eyes depends on a professional fitting, not on the CYL number alone.

Why does the contact lens cylinder differ from my glasses CYL?

The two principal powers change by different amounts when moved between the glasses and corneal planes. The converted CYL is calculated from the difference between those unrounded powers, then rounded for display.

Can I enter a plus-cylinder prescription?

Yes. The calculator transposes positive CYL into minus-cylinder notation before vertex conversion. Sphere and axis change as part of that equivalent notation; axis is rotated by 90°. To change notation without vertex conversion, use the cylinder transposition calculator.

Can I order toric contacts using this result?

This result is a theoretical optical equivalent. It does not determine your fitted product, base curve, diameter or on-eye rotation. Use a valid contact lens prescription and professional fitting; see the FDA contact lens guidance.

Keep Exploring Contact Lens Tools

More free tools: prescription conversion, lens prices, exam & fitting costs, and spherical equivalent. No sign-up.

Glasses & Contacts Calculator Convert theoretical lens power in either direction. Contact Lens Cost Calculator Estimate annual lens spending from your box prices. Exam & Fitting Cost Calculator Add quoted appointment fees and confirmed benefits. Spherical Equivalent Calculator Calculate SPH + CYL/2 as an average optical power. CYL Converter Transpose plus and minus cylinder prescriptions.