Skincare Routine Product Duration Estimator

1. Enter container amount
Use the product quantity in milliliters or convert another liquid measure before entering it.

2. Estimate one application
Enter the amount you actually use for one application.

3. Set daily frequency
Enter the average number of applications per day for this specific product.

4. Allow for waste or extra use
Add a percentage for product left in packaging, spills, or occasional heavier applications.

5. Review duration
Use the estimated days and yearly container count to plan repurchase timing.

Usable product = Container size × (1 − Waste rate)
Daily use = Amount per application × Applications per day
Duration in days = Usable product ÷ Daily use
Containers per year = 365 ÷ Duration in days

Where:

• Waste rate — entered percentage divided by 100

Assumptions: Usage is assumed to remain consistent across the estimate.

What the result means

Estimated days the product will last. Use it as a planning output based on the assumptions entered.

Usage estimate only. Follow product directions and professional advice for application and treatment decisions.

Given:
Container = 60 mL
Use per application = 1.0 mL
Applications = 2/day
Waste allowance = 4%

Calculation:
Usable product = 60 × 0.96 = 57.6 mL
Daily use = 1.0 × 2 = 2.0 mL
Duration = 57.6 ÷ 2.0 = 28.8 days
Containers/year = 365 ÷ 28.8 = 12.67

Result:
About 28.8 days per container and roughly 12.7 containers per year.

A change in application amount or frequency can materially change the estimate.