How does Stackpack forecast your spend?

Future months on the spend chart are a projection, not billed amounts. We fit a straight line through your completed monthly spend and extend it forward.

What the projection is based on

• The math uses the same period range the chart is set to. Widen the view to more months or years and the projection is recalculated over that longer history; narrow it and the projection follows a shorter, more recent run of months.

• On annual views we pull in a few extra months of history behind the first year shown. You won't see those months on the chart, but they're used to compute both the projection and the rolling twelve-month comparison, so the trend doesn't start cold at the January you happen to be looking at.

• Months before your spending with a vendor actually began are left out of the fit even when they appear on the chart as zeros, so a long quiet stretch doesn't flatten the trend.

• The current month is excluded, because it's still in progress and would make spend look like it's falling.

• One-off spikes — an annual renewal, a true-up, a credit — are softened rather than allowed to define the whole trajectory.

What you see

• The projected line is drawn from the current month forward, so it connects to your actual spend rather than starting from a gap.

• How far ahead it runs depends on the view; annual charts project whole future years, not the remaining months of the current one.

• Projections never go below zero, and with only one month of history we hold that amount flat instead of inventing a trend.

The result shows where spend is heading if current patterns hold.