Contact lens cost per day.

The short answer

Cost per day = (box price / lenses in the box) x lenses used per day, plus solution for reusable lenses. A 90-lens daily box at $90 for two eyes is $2.00 per day; a 6-lens monthly box at $30 with $12 monthly solution is $0.73 per day.

Worked example

Product A, daily lenses: $90 for 90 lenses is $1.00 per lens. Both eyes, worn 7 days a week: 730.00 lenses a year, $730.00. No solution. That is $2.00 per day ($60.83 a month).

Product B, monthly lenses: $30 for 6 lenses is $5.00 per lens. Both eyes, replaced every 30 days: 24.33 lenses a year, $121.67. Solution at $12 per 30 days adds $146.00. Total $267.67 a year, or $0.73 per day.

With these made-up prices monthly lenses are cheaper by $462.33 a year. Your prices decide the answer, so enter your own.

How it works

For daily lenses the tool counts one lens per eye per wearing day and throws the lens away: lenses a year = eyes x wearing days a week x 365 / 7. For two-week and monthly lenses it counts a replacement every N calendar days whatever you wore: lenses a year = eyes x 365 / N. Then lens cost = lenses a year x (box price / lenses per box), solution cost = bottle price x 365 / days per bottle (reusable lenses only), and the total is divided by 365 for a per-day figure, by wearing days for a per-wearing-day figure and by 12 for a monthly figure.

Assumptions. No tax, shipping, rebates, eye exam fees, cases, contact lens rewetting drops or insurance are included; one bottle of solution is assumed to last the number of days you enter; and the lens count assumes every lens is used as scheduled. Always follow the wearing and replacement schedule your eye-care professional gives you; stretching lenses to save money is not worth the eye health risk.

Sources: none needed. This is arithmetic on the prices and schedule you enter.

FAQ

How do I work out the cost per day of contact lenses?

Divide the box price by the number of lenses to get the price per lens, multiply by how many lenses you use per day (two for both eyes with dailies), and add solution for reusable lenses. The calculator does this for you.

Are daily lenses more expensive than monthly?

It depends on the prices you enter. Dailies need no solution, while monthlies need a lens every 30 days plus solution. With the example prices here, monthly lenses come out cheaper by $462.33 a year (about $2.00 per day for the dailies against $0.73 for the monthlies), but your own prices decide it.

What if I only wear contacts a few days a week?

For daily lenses the cost drops in proportion, since you only open a pair on days you wear them. Monthly and two-week lenses still have to be replaced on schedule, so the calendar cost stays the same.

Does this include the eye exam or contact lens fitting?

No. Exam fees, tax, shipping, rebates, cases and drops are not included. Add them to the price if you want them counted.

Should I stretch my lenses to save money?

No. Wear and replace lenses on the schedule your eye-care professional gives you. Overwearing raises the risk of eye problems.

Where do the prices come from?

You enter them. The defaults are made-up round numbers for the example and are not current market prices.