---
title: "Sensitivity analysis: definition and formula"
description: "Moving each input of a plan up and down by the same step to see which one changes the result most. It shows where to spend effort."
url: https://offersuite.io/glossary/sensitivity-analysis
updated: 2026-10-13
---

# Sensitivity analysis

Moving each input of a plan up and down by the same step to see which one changes the result most. It shows where to spend effort.

## In plain words

A sensitivity analysis takes a plan and nudges each input in turn: the price, the product cost, the acquisition cost, the renewal rate. Each is moved up and down by a set step while the others stay put, and the change in the result is recorded.

The output is a ranking. Some inputs barely move the result, and some move it a great deal. That tells you which numbers are worth getting exactly right, and which lever is worth pulling first.

## Formula

- Effect of an input = result with the input moved by the step − result as planned, all other inputs held

## Worked example

A coffee subscriber acquired for $30.00 is worth $23.29 of profit over twelve months. The engine moves five inputs in turn and ranks them.

Raising every renewal rate by five points changes that profit by $18.36, and raising the renewal price by 10% by $14.05. Moving the first-order price by 10% changes it by only $2.95.

### The example order

A $40.00 bag of coffee, shipped free, every cost counted

Revenue $40.00 to contribution margin $15.36 (38.4%)

Revenue

$40.00

Cost of goods

−$12.00

Pick and pack

−$1.18

Packaging

−$0.50

Shipping label

−$7.50

Card fee per order

−$0.30

Refunds

−$2.00

Card processing

−$1.16

Contribution margin

$15.36

2 declared kinds cost nothing on this option

Computed by the margin engine in Offer Suite's own code, in whole cents, from a $40.00 bag of coffee with a $12.00 unit cost.

## Sensitivity is not a forecast range

Moving one input at a time shows which input matters. It does not show how wrong the plan could be, because real inputs move together. For the range of outcomes, run many scenarios with the inputs varied at once.

## Using it

Use it to decide what to measure and what to test. If the result hangs on the renewal rate, spend your effort on knowing that rate and improving it. Arguing over a few cents of unit cost can wait. Rerun it when the plan changes: the most sensitive input for a new subscription is rarely the one for a mature one.

## In Offer Suite

For a subscription offer, Offer Suite's simulator reports how the profit per customer moves with the acquisition cost, the first-order and renewal prices, the product cost and the renewal rates, largest effect first.

Source: Offer Suite's offer simulator.

## Related

- [Glossary **Glossary of offer economics** The terms behind offer profit, defined plainly with their formulas and a worked number: contribution margin, profit per visitor, break-even lift and more.](https://offersuite.io/glossary)
- [Calculator **Subscription payback calculator: CAC and churn** How much a subscriber's first order loses against what you paid to acquire them, how many renewals it takes to earn that back with churn, and in which month.](https://offersuite.io/calculators/subscription-payback)
- [Calculator **Subscription first order vs renewal calculator** Margin on a subscription's first order and on each renewal, and the expected profit per subscriber over time at your retention, against a one-time buyer.](https://offersuite.io/calculators/subscription-first-order-vs-renewal)
- [Glossary **What-if analysis: definition, formula and example** Recomputing an offer's profit with one input changed, such as a cost or a price, and everything else held as it is today.](https://offersuite.io/glossary/what-if-analysis)
- [Glossary **Goal seek: definition, formula and example** Working backwards from a target to the input that reaches it: the price, acquisition cost or renewal rate at which a plan pays back.](https://offersuite.io/glossary/goal-seek)
- [Glossary **Customer lifetime value (LTV): definition** The profit a customer brings over the orders they stay for: the first order's margin plus each later order's, weighted by who is still buying.](https://offersuite.io/glossary/customer-lifetime-value)