The Excel SERIESSUM function evaluates a power series — it sums coefficients multiplied by rising powers of x, the building block behind many engineering and Taylor-series approximations.
Syntax
| Argument | Description | |
|---|---|---|
x | Required | The base value plugged into the power series. |
n | Required | The first power of x to use. |
m | Required | The step by which the power increases for each successive coefficient. |
coefficients | Required | The set of coefficients that multiply each successive power of x. One term is added per coefficient. |
How to use it
SERIESSUM builds the series a₁·xⁿ + a₂·xⁿ⁺₁ⁿ + a₃·xⁿ⁺₂ⁿ + ...: it starts at power n, raises the power by m for each coefficient, and multiplies by that coefficient.
With x=2, n=1, m=1 and coefficients {1,1,1}, the powers are 1, 2, 3, so the sum is 2¹ + 2² + 2³ = 14. Using an array constant in braces keeps the formula self-contained; in practice the coefficients are usually a cell range.
Why it matters: Taylor and Maclaurin series — the polynomial approximations behind functions like eₙ, sine, and cosine — are exactly this shape, which is why SERIESSUM is a staple in engineering models.
Try it: interactive demo
Pick a SERIESSUM example to see the formula and its result.
Practice workbook
Frequently asked questions
What do the n and m arguments control?
How is SERIESSUM(2,1,1,{1,1,1}) equal to 14?
Can I use a cell range for the coefficients?
What is SERIESSUM used for in practice?
Master functions like this in one day
This page covers one function. Our Excel Formulas and Functions class covers the 30 that matter most — live, hands-on, taught by professionals in Dallas–Fort Worth, Houston, Austin, Oklahoma City, Denver, or online.
See the Formulas & Functions Class