Generic Substitution Savings Calculator

Work out generic substitution savings instantly with clear inputs, formula shown and shareable results.

About Generic Substitution Savings Calculator

Compares brand and generic prices per fill and scales the difference across a year's refills.

Formula

Substitution saving

Annual saving = (brand cost - generic cost) x fills per year

Worked example

With the default values below, Generic Substitution Savings Calculator returns Annual saving of $1,860.00. Change any input above and every figure here is recalculated in your browser.

Inputs used

Brand cost per fillaccepts 0.01–100,000: 180
Generic cost per fillaccepts 0.01–100,000: 25
Fills per yearaccepts 1–52: 12

Results

Annual saving: $1,860.00
Saving per fill: $155.00
Saving as a share of the brand price: 86.11%
Annual generic cost: $300.00

Step by step

1Values used
2Substitution saving
3Annual saving= 1,860.00
4Saving per fill= 155.00
5Saving as a share of the brand price= 86.11
6Annual generic cost= 300.00

Assumptions and limits

The result is derived only from the 3 inputs listed above. Anything not among them is not part of the calculation.
In particular, this calculator does not take inflation or tax into account.
Figures are rounded for display to 2 decimal places, so totals built from several rounded parts can differ slightly from the unrounded arithmetic.

How these calculators are built and tested is described on the Methodology page. If a figure looks wrong, please report it.

Frequently Asked Questions

Are generics therapeutically equivalent?

Approved generics must demonstrate bioequivalence within accepted limits and contain the same active ingredient.

When is substitution inappropriate?

For narrow therapeutic index drugs and certain modified-release products where brand consistency is advised.