Act on the result
Investigate whether margin dollars or average inventory investment is the more controllable driver.
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
Retailers comparing gross margin earned with the average inventory cost committed for a measured period.
Outputs
Gross margin dollars, average inventory cost, period GMROI and explicitly annualised GMROI.
Start here
Use sales, cost of goods sold and average inventory cost from the same measured period.
Use a different tool when: Do not use this to measure inventory turnover and target working-capital change; use Inventory Turnover Planner for that decision. Use this tool to compare annualised gross margin earned with average inventory investment.
Commerce & operations
Gross Margin Return on Inventory: gross margin dollars
Gross margin dollars, average inventory cost, period GMROI and explicitly annualised GMROI.
Amounts use the same currency as your inputs. No currency conversion is performed.
Gross Margin Return on Inventory
Use your own inventory and commercial records on one consistent cohort, period, valuation and tax basis.
Your numbers stay in this browser
Measured sales for the selected period. Use one consistent ex-tax currency basis.
COGS matched to the same sales period. Use one consistent ex-tax currency basis.
Average inventory investment over the selected period. Use one consistent ex-tax currency basis.
Whole elapsed days represented by the sales and inventory records.
Enter your own gross-margin return target for the same period.
Decision result
Review the inventory result and its component rows on one consistent period and quantity basis.
- Gross margin
- 10,000.00
- Period GMROI
- 2×
- Annualised GMROI
- 2×
- Target gross margin
- 12,500.00
- Gross-margin gap to target
- 2,500.00
Scenario comparison
Each row names the assumption axis changed from the baseline.
ScenarioResultDifference
Entered scenario2.00Baseline
Lower Target GMROI2.000.00
Higher Target GMROI2.000.00
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.
Gross margin
Gross margin
sales − cost of goods sold10,000 , ex taxResult10,000.00
Uses the exact shared engine result and user-entered inventory records or scenarios. Raw engine precision is retained until display; whole-pack rounding occurs only in the engine.
Gross Margin Return on Inventory Planner formulas →Inputs used by these formula steps
- Gross marginSales Ex Tax
- 20,000
- Gross marginCost Of Goods Sold Ex Tax
- 10,000
- Gross marginAverage Inventory Cost
- 5,000
- Gross marginPeriod Days
- 365
- Gross marginTarget Gmroi
- 2.5
Period GMROI
Period GMROI
gross margin / average inventory at cost2 ratioResult2×
Uses the exact shared engine result and user-entered inventory records or scenarios. Raw engine precision is retained until display; whole-pack rounding occurs only in the engine.
Gross Margin Return on Inventory Planner formulas →Inputs used by these formula steps
- Period GMROISales Ex Tax
- 20,000
- Period GMROICost Of Goods Sold Ex Tax
- 10,000
- Period GMROIAverage Inventory Cost
- 5,000
- Period GMROIPeriod Days
- 365
- Period GMROITarget Gmroi
- 2.5
Annualised GMROI
Annualised GMROI
period GMROI × 365 / period days2 ratioResult2×
Uses the exact shared engine result and user-entered inventory records or scenarios. Raw engine precision is retained until display; whole-pack rounding occurs only in the engine.
Gross Margin Return on Inventory Planner formulas →Inputs used by these formula steps
- Annualised GMROISales Ex Tax
- 20,000
- Annualised GMROICost Of Goods Sold Ex Tax
- 10,000
- Annualised GMROIAverage Inventory Cost
- 5,000
- Annualised GMROIPeriod Days
- 365
- Annualised GMROITarget Gmroi
- 2.5
Target gross margin
Target gross margin
average inventory at cost × target GMROI12,500 , ex taxResult12,500.00
Uses the exact shared engine result and user-entered inventory records or scenarios. Raw engine precision is retained until display; whole-pack rounding occurs only in the engine.
Gross Margin Return on Inventory Planner formulas →Inputs used by these formula steps
- Target gross marginSales Ex Tax
- 20,000
- Target gross marginCost Of Goods Sold Ex Tax
- 10,000
- Target gross marginAverage Inventory Cost
- 5,000
- Target gross marginPeriod Days
- 365
- Target gross marginTarget Gmroi
- 2.5
Gross-margin gap to target
Gross-margin gap to target
target gross margin − gross margin2,500 , ex taxResult2,500.00
Uses the exact shared engine result and user-entered inventory records or scenarios. Raw engine precision is retained until display; whole-pack rounding occurs only in the engine.
Gross Margin Return on Inventory Planner formulas →Inputs used by these formula steps
- Gross-margin gap to targetSales Ex Tax
- 20,000
- Gross-margin gap to targetCost Of Goods Sold Ex Tax
- 10,000
- Gross-margin gap to targetAverage Inventory Cost
- 5,000
- Gross-margin gap to targetPeriod Days
- 365
- Gross-margin gap to targetTarget Gmroi
- 2.5
Inputs used
- Sales
- 20,000.00
- Cost of goods sold
- 10,000.00
- Average inventory at cost
- 5,000.00
- Period days
- 365
- Target GMROI
- 2.5
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 |
|---|---|---|---|---|---|
| averageInventoryCost | Average inventory investment over the selected period. Use one consistent ex-tax currency basis. | currency units averaged over the selected period, at cost | 0 to 10000000 | Required | 5000 |
| costOfGoodsSoldExTax | COGS matched to the same sales period. Use one consistent ex-tax currency basis. | currency units/period, ex tax | 0 to 10000000 | Required | 10000 |
| periodDays | Whole elapsed days represented by the sales and inventory records. | whole elapsed days/measurement period | 1 to 100000 | Required | 365 |
| salesExTax | Measured sales for the selected period. Use one consistent ex-tax currency basis. | currency units/period, ex tax | 0 to 10000000 | Required | 20000 |
| targetGmroi | Enter your own gross-margin return target for the same period. | gross-margin currency units/average inventory-cost currency unit | 0 to 1000 | Required | 2.5 |
Gross Margin Return on Inventory: gross margin dollars
Treat annualised GMROI as a period-normalised comparison, not a guarantee that the same margin and inventory pattern repeats.
Formula summary
- Primary formula
- gross margin / average inventory at cost.
Data used here
- The estimate uses your inputs and the general business formula documented in the methodology.
Decision checks
Stress-test the decision
Retest lower sales, higher cost of goods sold and a longer holding period.
When this estimate can be misleading
- Use one consistent inventory cohort, planning period, valuation basis and ex-tax currency basis where money applies.
- Targets, prevention rates and planned values are user-entered scenarios, not benchmarks or demand forecasts.
- Operational feasibility flags identify the entered constraints; they do not guarantee supplier availability or sales.
- This is educational business decision support, not accounting, tax, legal or financial advice.
- Treat annualised GMROI as a period-normalised comparison, not a guarantee that the same margin and inventory pattern repeats.
Educational estimate, not advice. See all assumptions & limitations →
Related reading
Guides to interpret the decision and its assumptions.
- Inventory Turn vs Stock Availability
Compare stock efficiency and availability on aligned periods without prescribing a universal turn or service target.
Read guide
Frequently asked questions
How do I compare annualised gross margin earned with average inventory investment?
Investigate whether margin dollars or average inventory investment is the more controllable driver.
Which planning assumptions should I stress-test?
Compare a plausible alternative scenario and verify the decision-critical assumption that changes the plan most.