Excel Trendline Start From a Different Point?

Yes. In Excel, a trendline is fitted to a chart series, so to start it at a later point, create a separate helper series containing only the data from your chosen start and add the trendline to that series. The built-in trendline settings do not let you choose a different first data point within an existing series.

How Excel trendlines work

A trendline summarizes the relationship between the values in a chart series. Excel calculates its equation from the usable points in that series, then draws the fitted line across the series’ range. For a linear trendline, the calculation finds a straight line that best fits the points; choosing a different subset can therefore change both the line’s slope and its position.

This distinction matters: changing where a line is drawn is not always the same as changing which points determine it. If you keep all the original points in the series, Excel still uses them to calculate the trendline, even if you want the visible line to begin later. To fit only recent data, the trendline needs its own series containing only that recent data.

For example, suppose a chart shows annual sales from 2019 through 2024, but a business change in 2022 makes you want a trendline for 2022–2024 only. A trendline attached to the original six-year series includes all six years. A trendline attached to a second series containing just the 2022, 2023, and 2024 values reflects the later period instead.

Make a trendline start at a later data point

The most dependable approach is to add a separate series for the selected period. Keep the original series if you still want to display all measured data, and make the helper series visually unobtrusive if its points would otherwise appear twice.

Arrange the horizontal values and measurements in separate columns. For example, put years 2019–2024 in A2:A7 and sales values in B2:B7. Put the chosen start year, 2022, in E1.
In C2, create a helper column that keeps the measurements from the chosen year onward and excludes earlier ones. Fill the formula down through C7.
Click the chart, then choose Chart Design > Select Data > Add. Give the new series a name, and set its X values to A2:A7 and its Y values to C2:C7. For a line chart using category labels, select the matching year labels and helper values instead.
Select the new series in the chart. Choose Chart Design > Add Chart Element > Trendline, then pick a trendline type. To choose a type or adjust its settings, open Chart Design > Add Chart Element > Trendline > More Trendline Options.
If the helper data points should not be visible, format the helper series so its line is set to No line and its markers are set to None. The trendline remains associated with that series.

Excel for Mac has similar chart-selection and trendline controls, although ribbon wording and layout can vary slightly by release. In Excel for the web, available chart editing options can also differ; use desktop Excel if a needed trendline setting is missing.

Use a helper formula to exclude earlier points

With years in A2:A7, measurements in B2:B7, and the chosen start year in E1, enter this formula in C2 and fill it down through C7:

=IF(A2>=$E$1,B2,NA())

For the example where E1 contains 2022, the helper results for 2019–2021 are #N/A, while the results for 2022–2024 are the corresponding values from column B. The formula uses the real Excel function NA() to mark earlier rows as unavailable, so they are not shown as ordinary data points. The trendline should be attached to this helper series, not to the original series.

This method changes the data used for the fitted line; it does not delete or alter the original measurements. If Excel fails to create the trendline or reports an error because of the excluded values, make a compact helper table containing only the selected years and measurements, then add that table as the trendline series. That avoids including error cells in the series range.

Choose the right chart type and start value

For data with numeric horizontal values—such as dates, elapsed time, distance, or temperature—a scatter chart is often the clearest choice. In a scatter chart, Excel uses the actual X and Y values. This matters when observations are unevenly spaced: a point three months later should be farther along the horizontal axis than one a week later.

A line chart is useful when the horizontal axis represents an ordered sequence of categories, such as months or product names. Its axis may space categories evenly, even if the labels resemble dates. If the intervals between observations are meaningful and unequal, consider a scatter chart before interpreting the slope. Excel offers trendlines for many two-dimensional chart types, but not every chart type supports them; if the Trendline command is unavailable, try a supported chart such as a scatter or line chart.

Choose the start point based on the question you are asking, not simply on which point makes the line look more convincing. A later start can be justified by a documented change in process, a new measurement method, or a clearly defined period of interest. It can also make a trend look stronger by excluding inconvenient earlier values, so label the period and explain why it was selected.

Trendline start point versus forecast and intercept

Excel’s Forecast settings in the Format Trendline pane extend a trendline backward or forward beyond the data used to fit it. Forecasting backward can make a line appear to begin before the first point, but it does not remove early observations from the calculation. It extrapolates the existing fitted relationship.

The Set Intercept option is different again. It forces the trendline equation to cross a specified vertical-axis value, usually at X = 0. It does not tell Excel to begin fitting at a particular year, date, or row. Forcing an intercept can materially change the fitted line, so use it only when the chosen intercept has a sound reason in the context of the data.

If the goal is only to hide the left portion of a line while keeping the original fit, changing the horizontal-axis bounds may crop what is visible. However, axis bounds affect the chart’s view and can also hide data or other series; they do not create a new fit or change which observations determine the trendline.

Common problems and how to fix them

The trendline still reflects early data: Check that it is attached to the helper series. Selecting the original data series and adding a trendline fits the original full range.
The helper points appear on top of the original points: Keep the helper series but format its markers as None and its line as No line. Do not delete the series, because the trendline depends on it.
The chart has gaps or error messages: Confirm that the helper range is correct. If #N/A values cause trouble in your chart or Excel build, create a compact table with only the included observations and chart that table.
The line starts at the wrong horizontal position: Check the X values assigned to the helper series and whether the chart is a scatter chart or a category-based line chart. In a scatter chart, the X range must match the selected Y range row by row.
The equation or R-squared value changed: That is expected when the fitted series changes. Both describe the selected points, not necessarily the original full dataset. A different subset can produce a different slope, intercept, and fit statistic.
The Trendline option is unavailable: The selected chart type may not support trendlines, or you may have selected a chart element rather than a data series. Select the series itself or try a supported two-dimensional chart.

When to use a custom calculated line

A separate trendline series is usually easiest when you want Excel to calculate and display a standard trendline. A custom calculated line can be useful when you need exact control over the displayed range, want to compare a particular model, or need to show predicted values as ordinary chart data. In that case, calculate the model from the intended observations, generate predictions only for the desired X values, and add those predictions as another chart series.

Keep the model’s calculation range and its display range conceptually separate. For example, a line might be fitted using 2022–2024 observations and displayed only from 2022 onward; alternatively, a model fitted on those years might be extrapolated into 2025. Extrapolation is a prediction beyond the observed range, not evidence that the historical trend will continue. Document the included period and model so readers can understand what the line represents.

Frequently Asked Questions

Can I drag an Excel trendline so it starts at a different point?
No. A built-in trendline is calculated from its chart series and is not an independently draggable line. Use a helper series to change the points used for the fit, or use axis bounds if you only need to crop the chart view.

Can I make a trendline start at the first point after a gap?
Yes. Create a series containing only the observations after the gap and add the trendline to it. If the gap marks a genuine change in the data-generating process, fitting separate periods may be more informative than forcing one line across both periods.

Does Forecast backward make the trendline start later?
No. Forecast backward extends a fitted trendline to the left of its data range. It does not exclude earlier points or move the start of the fitted period later.

Will changing the trendline start change its equation?
Usually, yes. If the new series excludes observations, Excel fits the trendline to a different set of values, which can change the equation and R-squared value.

Can I have two trendlines on one chart?
Yes. Add separate data series for the periods or groups you want to compare, then add a trendline to each series. Make the series and trendlines visually distinct and label the periods so the comparison is clear.

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Sources: Function behaviour and menu paths: Microsoft Support documentation for Excel. Method & sources

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