UTILS.
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Limit Calculator

Estimate the two-sided or one-sided limit of f(x) as x approaches a value or ±infinity by numeric sampling, and flag when the limit does not exist.

Enter f(x) and the value x approaches. Use inf or -inf for limits at infinity.

About this tool

The Limit Calculator is a free, in-browser calculus tool that estimates the limit of a function f(x) as x approaches a chosen point c — including c = +infinity or −infinity — by sampling the function numerically. For a finite c it evaluates f at points marching geometrically closer from each side, c ± 10⁻¹, 10⁻², … down to 10⁻¹³, and watches where the values settle. For c = ±infinity it instead samples at x = ±10¹, 10², … to see the end behaviour.

Everything is computed locally in your browser, so your input never leaves your device. You can choose a two-sided limit or restrict to the left-hand or right-hand limit. The tool compares the left and right sequences: if both converge to the same value L it reports that two-sided limit; if they disagree it shows each one-sided value and flags that the limit does not exist. Runaway magnitudes are reported as +∞ or −∞.

Type f(x) with the usual operators and functions (sin, cos, exp, ln, sqrt, …), the constants pi and e, and implicit multiplication like 2x. The approach point accepts numbers, small expressions, or inf / -inf. A classic example is sin(x)/x as x → 0: although the formula is 0/0 at the point itself, the samples from both sides converge to 1, so the calculator reports a limit of 1.

Frequently asked questions

How does it compute the limit?
Numerically. It evaluates f(x) at a sequence of points approaching c — from both sides for a two-sided limit — and reports the value the samples converge to. This estimates the limit without symbolic algebra, so it works for almost any expression you can type.
What does 'does not exist' mean here?
For a two-sided limit, if the left-hand and right-hand samples converge to different values (or one side diverges), the two-sided limit does not exist (DNE). The tool still shows each one-sided value so you can see the mismatch.
Can I take a limit at infinity?
Yes. Enter inf or -inf as the approach point and the tool samples x at ±10, ±100, ±1000, … to estimate the end behaviour. For example 1/x as x → inf gives 0, and (1+1/x)^x approaches e ≈ 2.71828.
Why does sin(x)/x give 1 at x = 0?
Substituting x = 0 gives the indeterminate form 0/0, but the function is well-behaved nearby. Sampling from both sides — at ±0.1, ±0.01, … — the values close in on 1, which is the correct limit the calculator reports.

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