Educational only: Business decision support, not accounting, tax or legal advice.
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Update policy: Reviewed when formulas or official dependencies change.
Scope: Market-neutral small-business planning using your own assumptions.
What this planner helps you decide
Best for
Businesses testing a price increase or decrease against the volume it would require.
Outputs
Required units, unit change and contribution at the proposed price.
Start here
Enter the current price, cost and volume, then change only the proposed price first.
Use a different tool when: Do not use this to set a price for a target gross margin; use Target Margin & Pricing Planner for that decision. Use this tool to find the sales volume needed to preserve contribution after changing price.
Decision pack · Step 3 of 5
Protect Margin
Move from a supplier-cost shock to a defensible price, realistic sales threshold and cash-impact check.
- 1. Measure the cost shock
- 2. Set the target price
- 3. Test allowable volume change
- 4. Confirm break-even
- 5. Review cash impact
Current decision: How much volume can change before profit falls below the baseline?
Next: Check the wider fixed-cost break-even threshold.Price & margin
Price–Volume Trade-off: required units
Required units, unit change and contribution at the proposed price.
Amounts use the same currency as your inputs. No currency conversion is performed.
Price and volume assumptions
Find the sales volume needed to preserve contribution after a price change.
Your numbers stay in this browser
Current price per unit.
Cost that changes with each unit.
Units sold in the comparison period.
Price to test for the same product.
Price-volume trade-off
Contribution comparison using amounts excluding indirect tax.
PDF and CSV exports stay on this device. Clean page links contain no inputs.
The entered-price marker and nearby engine scenarios show the volume needed to preserve current contribution.
Whole units required
- Current baseline units
- 100 units
| Proposed price (currency units ex indirect tax per unit) | Whole units required |
|---|---|
| 85.50 | 157 |
| 90.00 (current) | 134 |
| 94.50 | 116 |
Scenario comparison
Each row names the assumption axis changed from the baseline.
ScenarioResultDifference
Entered price134 unitsBaseline
Price 5% lower157 units23 units
Price 5% higher116 units-18 units
Save these results, change an input, then compare the updated figures with this baseline.
The baseline is temporary in this tab and is not added to shared scenario links or generated reports.
Calculation details
View calculation detailsView the formulas and inputs used for these results.
Whole units to preserve contribution
Current contribution
current contribution per unit × current units4,000/period ex indirect taxProposed contribution per unit
proposed price − unit cost30/unit ex indirect taxUnits needed to preserve contribution
current contribution ÷ proposed contribution per unit133.33 units/periodOperational whole-unit threshold
round required mathematical units upward134 units/periodResult134
Whole units per selected planning period, rounded upward. The mathematical threshold is rounded upward so contribution is not understated.
Price-volume formulas →Inputs used by these formula steps
- Current contributionContribution Per Unit
- 40
- Current contributionUnits
- 100
- Proposed contribution per unitProposed Price
- 90
- Proposed contribution per unitUnit Cost
- 60
- Units needed to preserve contributionBaseline Contribution
- 4,000
- Units needed to preserve contributionProposed Contribution Per Unit
- 30
- Operational whole-unit thresholdMathematical Units
- 133.33
Required volume change
Units needed to preserve contribution
current contribution ÷ proposed contribution per unit133.33 units/periodRequired volume change
required mathematical units ÷ current units − 133.33%Result33.3%
Compared with current units in the same planning period. Displayed to two percentage decimal places.
Required volume-change formula →Inputs used by these formula steps
- Units needed to preserve contributionBaseline Contribution
- 4,000
- Units needed to preserve contributionProposed Contribution Per Unit
- 30
- Required volume changeRequired Units
- 133.33
- Required volume changeCurrent Units
- 100
Current contribution
Current contribution per unit
current price − unit cost40/unit ex indirect taxCurrent contribution
current contribution per unit × current units4,000/period ex indirect taxResult4,000.00
Total contribution excluding indirect tax for the current planning period. Displayed to the nearest cent; the engine retains full precision.
Current contribution formula →Inputs used by these formula steps
- Current contribution per unitCurrent Price
- 100
- Current contribution per unitUnit Cost
- 60
- Current contributionContribution Per Unit
- 40
- Current contributionUnits
- 100
Current contribution per unit
Current contribution per unit
current price − unit cost40/unit ex indirect taxResult40.00
Per unit, excluding indirect tax. Displayed to the nearest cent; the engine retains full precision.
Unit contribution formula →Inputs used by these formula steps
- Current contribution per unitCurrent Price
- 100
- Current contribution per unitUnit Cost
- 60
Contribution at current volume
Proposed contribution per unit
proposed price − unit cost30/unit ex indirect taxContribution at current volume
proposed contribution per unit × current units3,000 per period ex indirect taxResult3,000.00
Proposed unit contribution applied to current units, excluding indirect tax. Displayed to the nearest cent; the engine retains full precision.
Contribution comparison formula →Inputs used by these formula steps
- Proposed contribution per unitProposed Price
- 90
- Proposed contribution per unitUnit Cost
- 60
- Contribution at current volumeProposed Contribution Per Unit
- 30
- Contribution at current volumeCurrent Units
- 100
Proposed contribution per unit
Proposed contribution per unit
proposed price − unit cost30/unit ex indirect taxResult30.00
Per unit at the proposed price, excluding indirect tax. Displayed to the nearest cent; the engine retains full precision.
Proposed unit contribution formula →Inputs used by these formula steps
- Proposed contribution per unitProposed Price
- 90
- Proposed contribution per unitUnit Cost
- 60
Inputs used
- Current price, excluding indirect tax
- 100.00
- Unit cost, excluding indirect tax
- 60.00
- Current units
- 100
- Proposed price, excluding indirect tax
- 90.00
Observed price elasticity
Describe one explicit before-and-after price and quantity pair with the midpoint arc method. This is descriptive evidence, not proof that price caused the quantity change.
- Observed arc elasticity
- -1.11
- Midpoint price change
- 9.52%
- Midpoint quantity change
- -10.53%
Calculation details
View calculation detailsView the formulas and inputs used for these results.
Observed arc elasticity
Observed arc elasticity
midpoint quantity change ÷ midpoint price change-1.11 ratioResult-1.11
Describes the two entered observations using midpoint changes; it is not causal attribution. The engine retains raw precision; display rounding does not feed calculation.
Observed arc-elasticity formulas →Inputs used by these formula steps
- Observed arc elasticityMidpoint Price Change Rate
- 0.1
- Observed arc elasticityMidpoint Quantity Change Rate
- -0.11
Observed midpoint price change
Observed midpoint price change
(after price − before price) ÷ midpoint price9.52%Result9.52%
Describes the two entered observations using midpoint changes; it is not causal attribution. The engine retains raw precision; display rounding does not feed calculation.
Observed arc-elasticity formulas →Inputs used by these formula steps
- Observed midpoint price changeObserved Before Price
- 100
- Observed midpoint price changeObserved After Price
- 110
- Observed midpoint price changeObserved Before Quantity
- 100
- Observed midpoint price changeObserved After Quantity
- 90
Observed midpoint quantity change
Observed midpoint quantity change
(after quantity − before quantity) ÷ midpoint quantity-10.53%Result-10.53%
Describes the two entered observations using midpoint changes; it is not causal attribution. The engine retains raw precision; display rounding does not feed calculation.
Observed arc-elasticity formulas →Inputs used by these formula steps
- Observed midpoint quantity changeObserved Before Price
- 100
- Observed midpoint quantity changeObserved After Price
- 110
- Observed midpoint quantity changeObserved Before Quantity
- 100
- Observed midpoint quantity changeObserved After Quantity
- 90
Inputs used
- Before price
- 100
- After price
- 110
- Before quantity
- 100
- After quantity
- 90
Conditional demand sensitivity
Apply your own elasticity bounds to a candidate price. The output is an assumption-led range, not a causal demand forecast or a sales promise.
- Conditional quantity low
- 80 units
- Conditional quantity high
- 95 units
- Candidate price change
- 10%
Calculation details
View calculation detailsView the formulas and inputs used for these results.
Conditional quantity low
Conditional quantity low
min(max(0, baseline quantity × (1 + elasticity bound × price change)))80 units/periodResult80 units
Conditional on the two user-entered elasticity bounds; this is not a causal forecast. The engine retains raw precision and floors negative scenario quantities at zero.
Conditional demand-sensitivity formulas →Inputs used by these formula steps
- Conditional quantity lowSensitivity Baseline Price
- 100
- Conditional quantity lowSensitivity Baseline Quantity
- 100
- Conditional quantity lowSensitivity Candidate Price
- 110
- Conditional quantity lowSensitivity Elasticity Lower Bound
- -2
- Conditional quantity lowSensitivity Elasticity Upper Bound
- -0.5
Conditional quantity high
Conditional quantity high
max(max(0, baseline quantity × (1 + elasticity bound × price change)))95 units/periodResult95 units
Conditional on the two user-entered elasticity bounds; this is not a causal forecast. The engine retains raw precision and floors negative scenario quantities at zero.
Conditional demand-sensitivity formulas →Inputs used by these formula steps
- Conditional quantity highSensitivity Baseline Price
- 100
- Conditional quantity highSensitivity Baseline Quantity
- 100
- Conditional quantity highSensitivity Candidate Price
- 110
- Conditional quantity highSensitivity Elasticity Lower Bound
- -2
- Conditional quantity highSensitivity Elasticity Upper Bound
- -0.5
Candidate price change
Candidate price change
candidate price ÷ baseline price − 110%Result10%
Conditional on the two user-entered elasticity bounds; this is not a causal forecast. The engine retains raw precision and floors negative scenario quantities at zero.
Conditional demand-sensitivity formulas →Inputs used by these formula steps
- Candidate price changeSensitivity Baseline Price
- 100
- Candidate price changeSensitivity Baseline Quantity
- 100
- Candidate price changeSensitivity Candidate Price
- 110
- Candidate price changeSensitivity Elasticity Lower Bound
- -2
- Candidate price changeSensitivity Elasticity Upper Bound
- -0.5
Inputs used
- Baseline price
- 100
- Baseline quantity
- 100
- Candidate price
- 110
- Elasticity lower bound
- -2
- Elasticity upper bound
- -0.5
Open this calculator with preset values
This calculator supports documented, shareable scenario URLs. Compatible assistants and applications can construct links using the parameters below.
Scenario links contain only allowlisted numeric and closed-choice inputs shown in the URL; Margin101 excludes free text and identifying fields. Anyone you share the URL with can read those numbers, so do not include private or identifying data.
| Parameter | Meaning | Unit | Allowed values | Presence | Default |
|---|---|---|---|---|---|
| baselinePrice | Current price per unit. | currency units/product unit, ex indirect tax | 0.01 to 10000000 | Required | 100 |
| baselineUnits | Units sold in the comparison period. | whole product units/comparison period | 1 to 10000000 | Required | 100 |
| proposedPrice | Price to test for the same product. | currency units/product unit, ex indirect tax | 0.01 to 10000000 | Required | 90 |
| unitCost | Cost that changes with each unit. | currency units/product unit, ex indirect tax | 0 to 10000000 | Required | 60 |
Price–Volume Trade-off: required units
Use the required-unit result to decide whether the proposed price can preserve contribution at a plausible sales volume.
Formula summary
- Primary formula
- required units = current contribution ÷ proposed contribution per unit
Data used here
- The estimate uses your inputs and the general business formula documented in the methodology.
Decision checks
Act on the result
Compare the required volume with recent sales and capacity before approving the new price or promotion.
Stress-test the decision
Test a less favourable proposed price and a higher unit cost to expose how quickly the volume requirement changes.
When this estimate can be misleading
- This is a contribution comparison, not a demand forecast.
- It assumes unit cost stays constant as volume changes.
- It excludes capacity, step costs, stock, cash timing and income tax.
- Use the required-unit result to decide whether the proposed price can preserve contribution at a plausible sales volume.
Educational estimate, not advice. See all assumptions & limitations →
Related reading
Guides to interpret the decision and its assumptions.
- How to Test a Price-Volume Trade-off
Compare price and unit contribution on the same period basis without pretending the calculation predicts customer demand.
Read guide
Frequently asked questions
How do I find the sales volume needed to preserve contribution after changing price?
Compare the required volume with recent sales and capacity before approving the new price or promotion.
Which planning assumptions should I stress-test?
Compare a plausible alternative scenario and verify the decision-critical assumption that changes the plan most.