Business case

    Legacy System Cost Calculator

    What is the old application actually costing you to keep alive?

    Most legacy applications are budgeted as a single licence line, which is why retiring them looks less valuable than it is. Enter what each component actually costs and the model returns an indicative annual saving, three-year saving and payback period.

    Your numbers

    All figures in pounds per year, except the one-off project estimate. Nothing is submitted — the calculation runs entirely in your browser.

    Including extended or third-party support
    Internal or outsourced application support effort
    Environments, licences for adjacent tools, audit remediation
    Leave blank if you do not have one yet

    What the model assumes

    Annual legacy costThe sum of every component you entered. In practice this is usually higher than the budgeted figure, because application support, DBA time and security remediation are rarely charged to the application.
    Annual archive costModelled as a proportion of the current annual cost, with a floor. An archive has no application licence, no application tier, no non-production copies and materially less support demand.
    First-year savingAnnual legacy cost, less the archive running cost, less the one-off implementation.
    Three-year savingThree years of annual saving, less the one-off implementation.
    Payback periodHow long the ongoing saving takes to recover the implementation cost.
    What the model does not knowYour contract notice periods and renewal dates. Those usually determine when the saving actually starts, and they are established during discovery.

    Indicative modelling only. Actual savings depend on contracts, infrastructure, support model and implementation scope.

    Request a Detailed Legacy Exit Assessment

    The calculator models one application from figures you already have. An assessment establishes the whole estate: what has to be retained, at what volume, under what retention rules, and what a scoped retirement would take.