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FREE INVENTORY CALCULATOR

Sales Velocity Calculator

Calculate sales velocity in units per day, compare sales rates across periods, and estimate unit demand for planning and replenishment.

  • Free to use
  • No sign-up required
  • Built for real inventory decisions

Calculator

Calculation Mode
units
Units sold in the current analysis period.
days
Days represented by current unit sales, up to 3650.
units
Units sold in the earlier comparison period.
days
Days represented by previous unit sales, up to 3650.
days
Future days used for the simplified demand projection.
units
Optional on-hand inventory used for coverage context.
days
Optional replenishment lead time used for demand context.

Results

Calculated
Current Daily Sales Velocity30 units/day

At the entered current sales rate, approximately 30 units/day sell each day.

Weekly Velocity210 units/weekDaily velocity × 7
30-Day Velocity900 units / 30 daysDaily velocity × 30
Annualized Velocity10,950 units/yearDaily velocity × 365
Current Period900 units30 days entered
Previous Daily Velocity25 units/dayPrevious entered period

Decision metrics

Velocity Difference+5 units/dayCurrent daily velocity − previous
Velocity Change+20%Relative to previous daily velocity
TrendIncreasingBased on the daily-velocity change
Planning Horizon30 daysYour selected projection period
Projected Demand900 unitsCurrent daily velocity × horizon
Lead-Time Demand420 units14 days of lead time
Inventory Coverage40 daysCurrent inventory ÷ daily velocity
Projected Inventory300 unitsAfter the planning horizon
Lead-Time Coverage2.86xCovers Lead-Time Demand
Decision Insight

Current sales velocity is approximately 30 units/day. This is +20% from 25 units/day in the previous period. The current rate implies 900 units of demand over the next 30 days. Estimated demand during the 14-day lead time is 420 units. Current inventory covers that level. With 1,200 units on hand, inventory covers about 40 days. These projections assume the current rate continues and are not demand forecasts.

Velocity Trend

Compare daily sales rates without treating the result as a forecast.

Previous
25 units/day
Current
30 units/day
Change
+20%
Trend
Increasing

Sales Velocity Comparison

Daily velocity normalizes sales across the two entered periods.

Daily Sales Velocity
Previous 25 units/day
Current 30 units/day

Planning Demand Bar

Compare projected demand with the inventory currently available.

300 units projected remaining after the planning horizon.

Key Takeaways

  • Sales velocity converts unit sales into a comparable daily rate, even when periods have different lengths.
  • Use velocity alongside lead time and inventory on hand to estimate near-term unit demand.
  • A sales-velocity change is a planning signal, not a demand forecast.
  • Compare consistent products, channels, and seasons before making replenishment decisions.

How It Works

Enter current units sold and the number of days in the current period to calculate daily sales velocity.

In Compare Periods mode, enter a previous period to measure the daily-velocity change and trend.

Choose a planning horizon to estimate unit demand if the current rate continues.

Optionally add inventory and lead time for operating context, including inventory coverage and lead-time demand.

Formula

Formula 1

Current Daily Sales VelocityCurrent Units Sold ÷ Current Period Length

Formula 2

Previous Daily Sales VelocityPrevious Units Sold ÷ Previous Period Length

Formula 3

Velocity DifferenceCurrent Daily Velocity − Previous Daily Velocity

Formula 4

Velocity Change(Current Daily Velocity − Previous Daily Velocity) ÷ Previous Daily Velocity × 100

Formula 5

Weekly VelocityCurrent Daily Velocity × 7

Formula 6

Planning-Horizon DemandCurrent Daily Velocity × Planning Horizon Days

Formula 7

Lead-Time DemandCurrent Daily Velocity × Lead Time Days

Formula 8

Inventory CoverageCurrent Inventory ÷ Current Daily Velocity

Where:

  • Sales Velocity: the number of units sold per day for the entered period.
  • Planning Horizon: the number of future days used for the simplified demand projection.
  • Lead-Time Demand: the units expected to be needed while a replenishment order is in transit.
  • Inventory Coverage: how many days current inventory would support at the current daily velocity.

Example Calculation

Let’s say:

  • Current Units Sold: 900 units
  • Current Period Length: 30 days
  • Previous Units Sold: 750 units
  • Previous Period Length: 30 days
  • Planning Horizon: 30 days
  • Current Inventory: 1,200 units
  • Lead Time: 14 days
Step 1: Current daily velocity = 900 ÷ 30 = 30 units per day. Step 2: Previous daily velocity = 750 ÷ 30 = 25 units per day. Step 3: Change = (30 − 25) ÷ 25 × 100 = 20%. Step 4: Projected 30-day demand = 30 × 30 = 900 units. Step 5: Lead-time demand = 30 × 14 = 420 units. Step 6: Inventory coverage = 1,200 ÷ 30 = 40 days.

The current rate is 30 units per day, up 20% from the previous period. At that rate, 1,200 units cover 40 days and exceed the 420 units needed during a 14-day lead time.

How to Use the Result

  • Use daily velocity to compare different periods fairly, including periods with different numbers of days.
  • Use the planning-horizon projection as a simple operating estimate, then consider promotions, seasonality, open orders, and known demand changes.
  • Compare lead-time demand with current inventory before deciding whether to replenish.
  • Use inventory coverage with Days of Supply and Reorder Point results for a broader replenishment view.
  • Investigate sharp changes before treating them as a lasting trend.

Limitations

  • Sales velocity is a historical rate, not a demand forecast.
  • The calculator assumes the current rate continues unchanged across the selected planning horizon.
  • Velocity can be distorted by promotions, stockouts, returns, new product launches, seasonal demand, and channel changes.
  • Compare like-for-like periods, products, and sales channels for the most useful trend signal.
  • Inventory coverage does not account for safety stock, open purchase orders, or reserved inventory.
  • A lead-time comparison does not replace a full reorder point calculation.
  • When the previous period has zero sales, percentage change is intentionally shown as New activity rather than an undefined percentage.

Frequently Asked Questions

What is sales velocity?

Sales velocity is the rate at which units sell over time, commonly expressed as units per day.

How do you calculate sales velocity?

Divide units sold by the number of days in the period: Units Sold ÷ Period Length.

Why calculate daily sales velocity?

A daily rate makes periods with different lengths comparable and supports demand and replenishment planning.

What is the difference between sales velocity and sell-through rate?

Sales velocity measures units sold per unit of time. Sell-through measures the share of available inventory sold during a period.

What is the difference between sales velocity and inventory turnover?

Sales velocity tracks unit movement over time. Inventory turnover compares COGS with average inventory over a period.

How is velocity change calculated?

The calculator compares current and previous daily velocity, then divides the difference by previous daily velocity.

Why does the calculator show New activity?

When previous daily velocity is zero and current velocity is positive, a percentage change would be undefined, so the tool shows New activity.

What happens when both periods have zero sales?

The tool reports No sales in either period and a No Activity trend instead of displaying an invalid percentage.

How is planning-horizon demand calculated?

It multiplies current daily velocity by the number of days in the planning horizon.

What is lead-time demand?

Lead-time demand is the estimated number of units needed while a replenishment order is in transit.

What is inventory coverage?

Inventory coverage estimates the number of days current inventory can support at the current daily sales velocity.

Can sales velocity predict demand?

No. It is a simplified projection based on the current rate and should be adjusted for known demand changes.

How often should I recalculate sales velocity?

Recalculate after meaningful demand, inventory, pricing, promotion, or seasonality changes, and as part of regular planning reviews.

Can I use this calculator at SKU level?

Yes. Use consistent unit-sales and period data for the SKU, product group, channel, or location you are reviewing.