What is Rolling forecast?
Actuals for closed months plus a re-cut forecast for the rest of the year — same horizon, refreshed every cycle.
A rolling forecast is a plan that moves with the calendar: closed months lock to actuals, the remaining months are re-forecast with what you now know, and the full-year number is implied by the join of the two. Instead of a January budget that's fiction by March, every cycle produces a current, honest view of where the year lands.
The mechanic is the formula: implied full year = actuals year-to-date + re-cut forecast for the remaining months. Nothing is rebuilt — each month one more column flips from forecast to actual, the forecast window shrinks by one, and the implied year re-anchors. The re-cut cadence is usually monthly; the horizon is usually the fiscal year or a fixed 4–6 quarters ahead.
What makes rolling forecasts hard in spreadsheets isn't the math — it's that the "same" view is rebuilt by hand every cycle, in workbooks that fork. Keep it as one query over the planning export and the roll-forward is mechanical: drop the new export, re-run, compare implied years.
Formula
Implied full year = actuals YTD + re-cut forecast for remaining months
The horizon can be rest-of-year or a fixed rolling window (e.g. 4+8 or 6 quarters) — rest-of-year is what the worked example uses, matching how planning tools export actual + forecast scenarios.
The Sumwise question
Build the rolling forecast: year-to-date actuals, the re-cut forecast for the rest of the year, and the implied full-year total per line item, biggest lines first.
Runs on rolling_forecast.csv. The same sample the rolling-forecast live demo runs on — actuals Jan–Sep plus the re-cut Oct–Dec forecast per line item.
Worked example — rolling_forecast.csv
| Revenue actuals, Jan–Sep (YTD) | $4,927,200 |
| Revenue re-cut forecast, Oct–Dec | $1,809,500 |
| Implied full-year revenue | $6,736,700 |
| Share of the implied year already locked | 73.1% |
The implied full year for revenue is $6,736,700 — 73.1% of it is already locked actuals, and only the $1.81M Q4 forecast is still an assumption.
rolling_forecast.csv — drop it into the demo's Your-own-CSV tab (or Excel) and re-run the example.
Common questions
How is a rolling forecast different from a budget?
A budget freezes at the start of the year and goes stale; a rolling forecast re-cuts the remaining months every cycle using what actually happened. Many teams run both — budget as the commitment baseline, rolling as the live view.
How far should it roll — rest of year or a fixed window?
Rest-of-year answers "where does this land" for the fiscal year; a fixed window (always 6 quarters ahead) answers "what does the next phase look like" independent of the calendar. Rest-of-year is the more common FP&A start, and it's what planning exports carry natively.
What does "rolling" cost in effort?
Done by hand, a full re-cut each month — which is why spreadsheet versions decay. As one saved query over the export, the incremental cost per cycle is dropping in the new file: actuals accumulate, the forecast shrinks, the implied year re-computes.
Compute rolling forecast on your own export, every month
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Related terms
Run rate
A trailing period's revenue annualized to a full year — the forward-looking size of the business.
Variance percent
How far an actual landed from its benchmark, as a share of the benchmark — (actual − plan) ÷ plan.
Seasonality
A pattern that repeats on a fixed calendar — measured as a seasonal index, period average ÷ overall average.