What is a sales forecast?
A sales forecast estimates how much you will sell in future periods. It drives almost every other plan in a business: how much stock to order, how many people to schedule and how much cash will come in. The simplest reliable method is to start from recent actual sales and apply the trend you expect.
Formula
Forecast for period n = last period’s sales × (1 + growth ÷ 100)ⁿ
Worked example
Last period you sold 5,000. With 5% growth each period, the next period comes to 5,250 and period 6 to 6,700.48. Across all 6 periods the forecast totals 35,710.04.
How to use the sales forecast calculator
- Enter your figures: sales in the last period, expected growth per period and periods to forecast.
- Read the result. It updates as you type, so there is no button to press.
- Try other numbers to compare scenarios. Reset brings back the example values.
Getting it right
- A period can be a week, a month or a quarter; just keep the growth rate on the same basis.
- Enter a negative growth rate to model a decline.
- For seasonal products, forecast from the same period last year instead of the period just ended.
Frequently asked questions
How do you calculate a sales forecast?
Multiply the last period’s sales by one plus the growth rate, and repeat for each period ahead. Sales of 5,000 growing 5% become 5,250, then 5,512.50, and so on.
What growth rate should I use?
Start from your own history: compare the last few periods with the ones before them. Then adjust for anything you know is changing, such as a new product, a price rise or a lost customer.
Should I forecast in units or in money?
Units are better for ordering stock and planning production. Money is better for budgets and cash flow. This calculator works with either.