What inputs does the Inventory Turnover Calculator need?

It takes 4 inputs: cogs, beginningInventory, endingInventory, periodDays (default 365). Outputs returned: averageInventory, turnover, daysInventoryOutstanding.

Can I verify the Inventory Turnover Calculator with a worked example?

Yes. With cogs = $1,200,000, beginning = $150,000, ending = $200,000, period = 365. the tool returns avg_inventory = $175,000, turnover ≈ 6.86×, dio ≈ 53 days.

Where does the Inventory Turnover Calculator get its benchmark data?

Reference data is sourced from: US Census Bureau — Manufacturing and Trade Inventories and Sales (M3) (as of 2024).

What can the Inventory Turnover Calculator not tell me?

Known limitations: Benchmarks differ sharply by industry. Grocers turn > 15× annually; high-end apparel may turn 3–4×. Seasonality masks issues: Q1 inventory totals for a Q4-heavy retailer are misleadingly low.

Methodology: Inventory Turnover Calculator

1. Scope

Calculates inventory turnover (COGS / average inventory) and days inventory outstanding. It is a trailing indicator and does not forecast demand or recommend re-order points.

2. Inputs and outputs

Inputs

cogs number (currency)

Cost of goods sold for the period.
beginningInventory number (currency)
endingInventory number (currency)
periodDays number default: 365

Outputs

averageInventory

(beginning + ending) / 2.
turnover

cogs / averageInventory.
daysInventoryOutstanding

periodDays / turnover.

Engine source: src/lib/inventory-turnover-calculator/engine.ts

3. Formula / scoring logic

avg_inventory = (beginning + ending) / 2
turnover      = cogs / avg_inventory
dio           = period_days / turnover

4. Assumptions

Average inventory = simple mean of start and end. Monthly-average is more accurate but not requested.
COGS uses the same costing basis (FIFO, weighted average, or specific identification) as the inventory valuation.
No adjustment for obsolete or write-down inventory.

5. Data sources

US Census Bureau — Manufacturing and Trade Inventories and Sales (M3) as of 2024

6. Known limitations

Benchmarks differ sharply by industry. Grocers turn > 15× annually; high-end apparel may turn 3–4×.
Seasonality masks issues: Q1 inventory totals for a Q4-heavy retailer are misleadingly low.

7. Reproducibility

Input
cogs = $1,200,000, beginning = $150,000, ending = $200,000, period = 365.

Expected output
avg_inventory = $175,000, turnover ≈ 6.86×, dio ≈ 53 days.

8. Change log

2026-04-24 methodology page first published.

Worked example

Run live against the same engine this site ships (/engines/inventory-turnover-calculator.js). The inputs and outputs below are recomputed on every build and independently re-verified in CI — they are never hand-authored.

Input

tool: inventory_turnover
cost_of_goods_sold: 500000
beginning_inventory: 80000
ending_inventory: 70000
period: annual

Output

averageInventory: 75000
turnoverRatio: 6.67
dsi: 54.72
annualizedTurnover: 6.67
rating: healthy
ratingLabel: Healthy Turnover
ratingNote: Inventory is cycling at a solid pace. Monitor DSI trends to stay ahead of demand shifts.
benchmarks[0].industry: Grocery
benchmarks[0].min: 14
benchmarks[0].max: 20
benchmarks[1].industry: Retail
benchmarks[1].min: 8
benchmarks[1].max: 12
benchmarks[2].industry: E-Commerce
benchmarks[2].min: 6
benchmarks[2].max: 10
benchmarks[3].industry: Manufacturing
benchmarks[3].min: 4
benchmarks[3].max: 8
benchmarks[4].industry: Wholesale
benchmarks[4].min: 5
benchmarks[4].max: 9
benchmarks[5].industry: Automotive
benchmarks[5].min: 3
benchmarks[5].max: 6
assumptionsEcho.cogs: 500000
assumptionsEcho.averageInventory: 75000
assumptionsEcho.period: annual

Frequently asked questions

What does the Inventory Turnover Calculator calculate?: Calculates inventory turnover (COGS / average inventory) and days inventory outstanding. It is a trailing indicator and does not forecast demand or recommend re-order points.
What inputs does the Inventory Turnover Calculator need?: It takes 4 inputs: cogs, beginningInventory, endingInventory, periodDays (default 365). Outputs returned: averageInventory, turnover, daysInventoryOutstanding.
What formula does the Inventory Turnover Calculator use?: The exact computation is: avg_inventory = (beginning + ending) / 2; turnover = cogs / avg_inventory; dio = period_days / turnover
Can I verify the Inventory Turnover Calculator with a worked example?: Yes. With cogs = $1,200,000, beginning = $150,000, ending = $200,000, period = 365. the tool returns avg_inventory = $175,000, turnover ≈ 6.86×, dio ≈ 53 days.
Where does the Inventory Turnover Calculator get its benchmark data?: Reference data is sourced from: US Census Bureau — Manufacturing and Trade Inventories and Sales (M3) (as of 2024).
What can the Inventory Turnover Calculator not tell me?: Known limitations: Benchmarks differ sharply by industry. Grocers turn > 15× annually; high-end apparel may turn 3–4×. Seasonality masks issues: Q1 inventory totals for a Q4-heavy retailer are misleadingly low.