Truncation error or local truncation error (LTE) is error made by numerical algorithms that arises from taking finite number of steps in computation. It is present even with infinite-precision arithmetic, because it is caused by truncation of the infinite Taylor series to form the algorithm.
Use of arbitrarily small steps in numerical computation is prevented by round-off error, which are the consequence of using finite precision floating point numbers on computers.
Local Truncation error for a single step method: Τi+1(h)= ( yi+1 - yi ) / h - Φ(ti,yi)