The Challenge of Justifying the Project
"To defend our project with the board, I can't just say we'll improve the sales forecast by X%. The director doesn't feel that in the bottom line."
It makes perfect sense. Sales forecast quality needs to be translated into financial language to gain traction in the organization. Let's show how to make this conversion in a structured way.
Market References
For each 1% improvement in forecast accuracy, two widely recognized market references help us size the impact:

IBF (Institute of Business Forecasting)
0,20%
increase in profitability per 1% improvement

McKinsey & Company
0,50%
reduction in total inventory cost per 1% improvement
By extrapolation, improving accuracy by 20 percentage points could represent around 4% gain in profitability. However, these numbers are global averages β each company feels this impact differently, with many variables involved.
Going Beyond Benchmarks
We don't need to rely exclusively on market benchmarks. It's possible to break down cost components and calculate the real financial impact by looking at your own operation's costs.
Forecast error generates two types of financial impact, each with its own cost components:
π Over-forecast: When We Aim Too High
When the forecast exceeds actual demand, the operation produces and buys more than necessary:
Excess finished goods inventory
Expired products and obsolete raw materials
Additional warehousing costs
Tied-up working capital
All of this erodes margins and immobilizes capital that could be generating returns in other areas of the business.
π Under-forecast: When We Aim Too Low
When the forecast falls below actual demand, the company cannot adequately serve the market:
Stockouts and delayed orders
Order cancellations
Urgent production, overtime, and out-of-sequence setups
Express freight to try to recover deadlines
In this scenario, the company literally leaves money on the table β lost sales and inflated operational costs.
From Accuracy to Results
When we put a price on these two effects, each 1% of accuracy becomes a tangible financial value. This is the language that allows discussing sales forecasting with the board in an objective and convincing way.
On the nPLAN website, we provide a Savings calculator that allows you to visualize typical gains by company size and simulate with your real operational data.