Simpson's Rule Calculator
Integrate with the 1/3 and 3/8 rules, with the weight pattern shown, the subinterval count adjusted when it must be, and the error bound.
Related tools
All Calculus tools →Open Simpson's Rule Calculator and you get an answer straight away, with no account to create. Its place is under Calculus; Cramer's Rule Calculator and Descartes' Rule of Signs Calculator answer the questions closest to this one.
How to use it
- Open the tool — no signup or install needed.
- Enter your input or adjust the available options.
- Get your result instantly, then copy or download it.
Frequently asked questions
What is Simpson's Rule Calculator?
Integrate with the 1/3 and 3/8 rules, with the weight pattern shown, the subinterval count adjusted when it must be, and the error bound.
When would I actually use this?
Checking a derivative or an integral you worked out by hand, finding where a function turns, and getting a numeric answer when no closed form exists.
What is the most common mistake?
Integrating across a discontinuity as if it were not there. A numeric method will happily return a finite value for an integral that diverges — check the domain before trusting the number.
How is Simpson's Rule Calculator different from Cramer's Rule Calculator?
They sit next to each other but answer different questions: Cramer's Rule Calculator is the one to open when you need it to solves a 2×2 or 3×3 system with exact fractions, shows every determinant expanded term by term, and when D = 0 separates the two cases most calculators merge: dependent with infinitely many solutions, or inconsistent with none. Pick whichever matches what you're starting from — both are free.
Is there a tool for the next step?
Descartes' Rule of Signs Calculator is the closest one after this: Sign changes in f(x) and f(−x) marked one by one, then every possible (positive, negative, complex) combination that adds up to the degree.
What else is worth having open alongside it?
Trapezoidal Rule Calculator and Rule of three — they come up in the same task often enough to be worth a second tab.
Where do the figures come from?
Symbolic results are exact; numeric ones come from adaptive quadrature or a standard step method, and the tool reports which. Where both are available, compare them — a large gap means the problem is ill-conditioned.