Statistical
FORECAST.LINEAR Function in Excel
Calculates a future value using linear regression.
Syntax
- =FORECAST.LINEAR(x, known_y's, known_x's)
Arguments
- x (required): Data point to predict value for
- known_y's (required): Dependent data range
- known_x's (required): Independent data range
Examples
- =FORECAST.LINEAR(15, B2:B10, A2:A10) - Predict Y when X=15 - Result: Predicted value
Excel FORECAST.LINEAR function documentation
- FORECAST.LINEAR predicts a future y value using linear regression on known x-y pairs.
- Syntax: =FORECAST.LINEAR(x, known_y's, known_x's). Replaces legacy FORECAST.
- Use for trend extrapolation when relationship is approximately linear.
- Related: [TREND](/functions/trend/), [SLOPE](/functions/slope/), [INTERCEPT](/functions/intercept/), [LINEST](/functions/lin-est/).
FORECAST.LINEAR syntax
- x: independent value you want prediction for.
- known_y's and known_x's: historical paired data same length.
- Assumes linear fit — poor for curved data — check scatter plot.
- #N/A if insufficient variation in known_x's.
Step-by-step: forecast next month sales
- Step 1 — Month index 1..12 in A, sales in B.
- Step 2 — Next month x=13: =FORECAST.LINEAR(13, B2:B13, A2:A13).
- Step 3 — Compare [TREND](/functions/trend/) for array of forecasts.
- Step 4 — Chart line + forecast point for stakeholders.
- Step 5 — Seasonal data — linear forecast may fail — use moving average or seasonality model.
FORECAST.LINEAR vs TREND vs GROWTH
- FORECAST.LINEAR — single x prediction.
- TREND — array of fitted y values.
- GROWTH — exponential trend.
- Analysis guide: [/guides/best-excel-functions-for-data-analysis/](/guides/best-excel-functions-for-data-analysis/).
Worked examples to copy
- Single point: =FORECAST.LINEAR(25, y_range, x_range).
- From cell x: =FORECAST.LINEAR(E1, B:B, A:A).
- With IFERROR: =IFERROR(FORECAST.LINEAR(x,y,x), "N/A").
- Check line: =SLOPE(y,x)*x+INTERCEPT(y,x) equivalent.
People also ask
- FORECAST vs FORECAST.LINEAR? — FORECAST deprecated alias in modern Excel.
- FORECAST.LINEAR confidence? — No interval — use LINEST or add-in for stats.
- FORECAST.LINEAR seasonal data? — Often wrong — de-season first.
- FORECAST.LINEAR Google Sheets? — FORECAST or LINEST equivalents.
Common errors
- Arrays must be same size
- #N/A if no variance in x
Use cases
- Sales forecasting
- Trend prediction
- Linear projection
Frequently asked questions
- How do I forecast next month's sales? If you have monthly sales data with months numbered 1-12, use =FORECAST.LINEAR(13, SalesRange, MonthRange) to predict month 13. The function fits a line through your data and extrapolates to the new point.
- What is the difference between FORECAST.LINEAR and TREND? FORECAST.LINEAR predicts a single value for one x. TREND can predict multiple values at once and can handle multiple independent variables. For simple single-point prediction, FORECAST.LINEAR is easier.
- How accurate is FORECAST.LINEAR? Accuracy depends on how linear your data actually is. Check R² (=RSQ(y_range, x_range)) - values close to 1 mean good linear fit. For non-linear data, consider FORECAST.ETS or polynomial regression instead.
Editorial review
- Reviewed by Excel.Directory Editorial Team. Updated May 2026.
When to use FORECAST.LINEAR
- Sales forecasting — common Statistical scenario for FORECAST.LINEAR.
- Trend prediction — common Statistical scenario for FORECAST.LINEAR.
- Linear projection — common Statistical scenario for FORECAST.LINEAR.
FORECAST.LINEAR in the Statistical category
- Browse all Statistical functions at /categories/statistical/ for related formulas.
- FORECAST.LINEAR syntax: =FORECAST.LINEAR(x, known_y's, known_x's)
- x (required): Data point to predict value for
- known_y's (required): Dependent data range
- known_x's (required): Independent data range
- Confirm FORECAST.LINEAR arguments match the syntax shown above before filling down.
- Lock table and range references with $ when copying formulas across rows or sheets.
Formula checklist before you copy down
- Confirm FORECAST.LINEAR arguments match the syntax shown above before filling down.
- Lock table and range references with $ when copying formulas across rows or sheets.
- If results look wrong, check for text stored as numbers and invisible spaces with TRIM.
- Spot-check three known input rows manually against expected output.
Related Excel functions
- TREND (/functions/trend/): Returns values along a linear trend.
- SLOPE (/functions/slope/): Returns the slope of the linear regression line.
- INTERCEPT (/functions/intercept/): Returns the y-intercept of the linear regression line.
- LINEST (/functions/linest/): Returns the parameters of a linear trend using least squares method.
Errors to watch for
- Arrays must be same size — review causes on linked error pages in the directory.
- #N/A if no variance in x — review causes on linked error pages in the directory.
Copy-paste audit workflow
- Enter FORECAST.LINEAR on three test rows with known expected output documented on a QA tab.
- Fill down only after absolute references are locked on lookup tables and rate tables.
- Compare against manual calculation or a calculator for financial and statistical functions.
- Search this directory for comparison guides when choosing between similar functions in the same category.
FORECAST.LINEAR worked examples to copy
- =FORECAST.LINEAR(15, B2:B10, A2:A10) — Predict Y when X=15. Expected result: Predicted value.
FORECAST.LINEAR reference summary for crawlers and offline review
- FORECAST.LINEAR belongs to the Statistical category in Excel. Calculates a future value using linear regression.
- Full syntax: =FORECAST.LINEAR(x, known_y's, known_x's). Open /functions/forecast-linear/ for parameters, FAQs, and related pages.
- Common mistakes: Arrays must be same size; #N/A if no variance in x
- Pair this function with comparison guides when another Excel formula might fit the same task better.
- Review fix-excel-formula-errors when unexpected errors appear after upgrading Excel or sharing across locales.