Composite Trapezoidal Rule Calculator

When dealing with numerical methods for integration, the Composite Trapezoidal Rule stands out as a reliable approach for approximating the value of a definite integral. This method provides a straightforward way to compute the area under a curve, even when the function is complex or lacks an elementary antiderivative.


The Composite Trapezoidal Rule formula is given by:

I = h/2 * (y0 + 2y1 + 2y2 + ... + 2yn-1 + yn)


  • I represents the approximation of the integral.
  • h denotes the width of the subintervals.
  • y0, y1, ..., yn are the function values at nodes.

How to use:

  1. Enter the width of subintervals (h) in the provided field.
  2. Input the function values at nodes (y0, y1, ..., yn), separated by commas.
  3. Click the "Calculate" button to obtain the approximation of the integral.


Let's say we want to approximate the integral of a function using the Composite Trapezoidal Rule. Given the width of subintervals (h) as 0.1 and function values at nodes as [1, 2, 3, 4], we can compute the approximation as follows:

Width of Subintervals (h): 0.1 Function Values at Nodes (y0, y1, …, yn): 1,2,3,4 Approximation of the Integral (I): [Result will be displayed here upon calculation]

Clicking the "Calculate" button will yield the approximation of the integral.


  1. What is the Composite Trapezoidal Rule?
    • The Composite Trapezoidal Rule is a numerical method used to approximate the value of a definite integral by dividing the interval into subintervals and applying the trapezoidal rule to each subinterval.
  2. When should I use the Composite Trapezoidal Rule?
    • This method is particularly useful when the integrand function is smooth and well-behaved over the interval of integration.
  3. How accurate is the Composite Trapezoidal Rule?
    • The accuracy of the approximation depends on the width of the subintervals and the behavior of the function. Generally, increasing the number of subintervals leads to a more accurate result.
  4. Can the Composite Trapezoidal Rule handle non-uniform intervals?
    • Yes, this method can be extended to handle non-uniform intervals by adjusting the width of each subinterval accordingly.
  5. What are the limitations of the Composite Trapezoidal Rule?
    • One limitation is that it may not provide accurate results for functions with sharp corners or discontinuities within the interval of integration.


The Composite Trapezoidal Rule Calculator simplifies the process of approximating definite integrals, offering a convenient tool for numerical analysis and scientific computing tasks. By inputting the width of subintervals and function values at nodes, users can swiftly obtain reliable estimates of integrals, facilitating various mathematical applications with ease.