In general, with either conversion or new implementation, there’s a good chance you’ll spend somewhat more than you have planned, but you don’t want to dig yourself into a big financial hole in either case. It is useful to bear in mind that if your SAP ECC system is not fit for one-step conversion (because of its technical and functional aspects), or your system is not at the minimum release level specified for one-step conversion, or out of maintenance system, or a non-Unicode system, or Dual-stack system: conversion activity may cost almost as much as a Greenfield implementation, and during conversion, there’s a distinct possibility that an unexpected situation may crop up, pushing costs up further. My view is that the best choice is the one that incurs minimum deployment costs, minimum complexity, minimum disruption of users’ time, minimum downtime, retention of existing desirable functionality and minimum working hours to be able to execute the business processes on digital core and on the digital value network. “Choosing the best” requires a scientific approach suggested by SAP and needs to consider the suggestions of experienced SAP S/4HANA Conversion experts. Both options have their merits, demerits and difficulties. The choice is not always simple and indeed depends on many factors. Many IT heads are currently in a quandary about the choice between converting their existing SAP ECC system to S/4HANA, or starting from scratch and doing a Greenfield SAP S/4 HANA Implementation.