B2B sales forecasting: methods, forecast categories and an example
Sales forecasting in B2B means estimating the revenue a company will close in a given period, based on open opportunities, historical win rates and salespeople's judgement. This article describes three forecasting methods, the forecast categories used in CRM systems, a worked example, a measure of forecast accuracy and common mistakes.
Amounts and values in the examples are illustrative and show how the calculation works. In projects, we use the client's data.
Dominik Dębski · Lemur Media · · reading time: 4 min
Reviewed by Dominik Dębski, 1 November 2026
What is sales forecasting?
Sales forecasting is estimating the value of revenue the sales team will close in a period, based on verifiable funnel data and historical win rates. A forecast differs from a sales plan: the plan sets the target, the forecast estimates how much of that target the company will actually achieve. Decisions on hiring, liquidity, purchasing and communication with investors or the bank rest on the forecast. That is why the board judges it by its accuracy, measured after the period ends.
Which forecasting methods are used in B2B?
Three basic methods are used in B2B: forecast categories assessed by salespeople, a funnel weighted by stage probability, and a historical forecast. The best results come from comparing at least two methods and explaining the difference between them.
| Method | How it works | When it makes sense | Limitation |
|---|---|---|---|
| Forecast categories | The salesperson assigns the opportunity to a category based on confidence of closing in the period | Few large opportunities, long cycle | Depends on the salesperson's judgement and experience |
| Weighted funnel | Opportunity value × historical win rate from the given stage | Many opportunities of similar size | Requires reliable stages and up-to-date dates |
| Historical forecast | Trend and seasonality of revenue from previous periods | Recurring sales, renewals | Does not see changes in the funnel or the market |
Which forecast categories are used in the CRM?
Forecast categories group opportunities by confidence of closing in the period; in Salesforce the standard categories are Pipeline, Best Case, Most Likely, Commit, Closed and Omitted. Systems allow categories to be linked to funnel stages, but the company sets the category definitions itself. Below is an example set of criteria.
| Category | Meaning | Example entry criterion |
|---|---|---|
| Closed | Opportunity won in the period | Signed contract or order |
| Commit | Closing in the period is very likely | Decision-maker has confirmed the choice, formal path known, signature date within the period |
| Best Case | Closing in the period possible under favourable circumstances | Proposal submitted, decision within the period, no confirmation from the decision-maker |
| Pipeline | Open opportunity with a close date in the period, at an early stage | Qualified opportunity before a proposal is submitted |
| Omitted | Opportunity excluded from the forecast | Lost or moved outside the period |
What does a worked example look like?
The quarterly forecast is calculated as the sum of revenue already closed and the value of opportunities in each category multiplied by that category's historical conversion rate. The conversion rate is the share of the value of opportunities in a given category at the start of the quarter that was won in the same quarter, calculated over the last four quarters.
| Category | Opportunity value | Historical conversion | Contribution to the forecast |
|---|---|---|---|
| Closed | PLN 800,000 | 100% | PLN 800,000 |
| Commit | PLN 600,000 | 90% | PLN 540,000 |
| Best Case | PLN 900,000 | 40% | PLN 360,000 |
| Pipeline | PLN 2,400,000 | 10% | PLN 240,000 |
| Forecast | PLN 1,940,000 |
If the quarter closes at PLN 1,820,000, the error is PLN 120,000, i.e. 6.6% of the actual, and accuracy is 93.4%. Accuracy is measured in successive weeks of the quarter, separately for each salesperson and team. This shows whose judgement needs correcting and from which week the forecast is reliable.
Which mistakes reduce forecast accuracy?
- Categories without written entry criteria, so each salesperson understands Commit differently.
- Opportunities with outdated close dates, pushed from quarter to quarter without recording the reason.
- Forecast equal to the plan: the team reports the target instead of an assessment.
- No measurement of accuracy after the period ends and no comparison of methods.
- A forecast based on the number of opportunities without taking their age into account: opportunities much older than the median cycle have a lower chance of winning.
- Changes to the forecast in the last weeks of the quarter without analysing which opportunities changed category.
How do you run a weekly forecast review?
The forecast review is a fixed weekly meeting at which the sales manager goes through category changes and the largest opportunities with each salesperson, and the result goes to the board in a single format. The meeting is shorter and produces better data if it focuses on changes since the previous week.
- Category changes: opportunities that entered or dropped out of Commit, with the reason.
- Opportunities with a moved close date and the number of previous moves.
- The largest opportunities in the Commit and Best Case categories with missing qualification elements.
- Comparison of the category-based forecast with the weighted funnel and an explanation of the difference.
- One forecast figure per team, with a conservative and an optimistic scenario.