Sales Forecast Template (Excel and Google Sheets)

This sales forecast template shows the structure of a simple monthly forecast that you can set up in Excel or Google Sheets in an hour: an assumptions block, a calculation block that multiplies units by price, a summary and an accuracy tracker. We show the layout and formulas in full below so you can build it yourself, with a worked three-month example. It supports the planning process described in budgeting and forecasting. If you would rather have a model built for your business, get in touch.

Sheet 1: Assumptions

Every number you type goes here, with a note on its source. Nothing is typed anywhere else.

Keep a short notes column for the owner of each assumption and the date it was last reviewed.

Sheet 2: Forecast

One block per product, one column per month.

(Illustrative numbers.) The three-month total is $204,228.70.

Formulas

Assuming the starting units are in Assumptions!B2 and growth in Assumptions!B3:

Jan units:       =Assumptions!B2
Feb units:       =B5*(1+Assumptions!$B$3)       (previous month times growth)
Revenue:         =Units*Price
Total revenue:   =SUM of product revenues

To apply seasonality, multiply the units by the month's index: =B5*(1+growth)*SeasonIndex. Check the indices average 1.0 over the year.

Sheet 3: Summary

Add one chart: monthly revenue, forecast against last year's actual.

Sheet 4: Accuracy tracker

Save a copy of the forecast each month before you overwrite anything, so you can measure accuracy and bias. See how to measure financial forecast accuracy.

Adding low and high cases

A single forecast hides risk. Add two extra columns of growth assumptions and let the same formulas run three times. For Product A in March, with starting units of 1,000 and price $40:

(1,000 × 1.02 × 1.02 = 1,040.4; 1,000 × 1.04 × 1.04 = 1,081.6.) The spread is small after three months but widens quickly over a year: at 12 months the high case is about 1,000 × 1.04^11 = 1,539 units against 1,243 for the base case (1.02^11 = 1.2434). Show the range to whoever relies on the number. See sensitivity analysis in financial models.

If your revenue recurs

For subscriptions or contracts, units are better modeled as subscribers or accounts with a churn rate and new sign-ups, not as simple growth. See SaaS revenue forecasting for that structure; the assumptions-forecast-summary-tracker layout above still applies.

Set-up mistakes to avoid

• Typing numbers into the forecast sheet instead of the assumptions sheet.
• Overwriting last month's forecast so accuracy cannot be measured.
• Growth rates copied from the target, not from history.
• Seasonality indices that do not average 1.0.
• No check that the monthly figures add to the annual total.

Using the template well

1. Fill the assumptions from actual data, not from the target.
2. Build a low and high case by changing growth and price.
3. Update monthly with actuals and re-forecast the remaining months.
4. Review the forecast with sales and operations before it is used for purchasing or hiring.
5. Check the margin behind the revenue. See unit economics.

For a method to build the drivers, read how to forecast revenue. If you sell a new product with no history, see forecasting sales for a new product.

FAQs

What should a sales forecast template include?

Assumptions, a forecast calculation by product and month, a summary and an accuracy tracker.

Can I use the same template in Excel and Google Sheets?

Yes. The formulas shown work in both.

How often should I update it?

Monthly, with actuals, and re-forecast the remaining months.

Is a template enough?

For a simple business, yes. For more complex needs, such as many products or a long sales cycle, a custom model may be better. Contact us to discuss.