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ERP Selection Timeline Calculator: How Long Will Selection Take?

How long an ERP selection takes is one of the first questions a CIO has to answer for the board. This calculator adds up the stages, requirements, RFP, vendor response, demos, scoring, negotiation and approval, then applies a contingency. It gives a defensible range before you commit to a date.

Your numbers

Requirements gathering

6 weeks

Process workshops, prioritization and sign-off

RFP preparation

3 weeks

Writing the RFP, legal review, vendor longlist

Vendor response period

4 weeks

Includes the question and answer window

Vendors in scripted demos

3 vendors

Demo days per vendor

Demo days your team can attend per week

Negotiation and legal

6 weeks

Commercial terms, order form, statement of work

Executive and board approval

3 weeks

Contingency

15 percent

Allowance for holidays, slips and rework

Your results

Estimated duration with contingency

32.2 weeks

Estimated duration in months

7.4 months

Scripted demo phase

2 weeks

Total demo days divided by days your team can attend each week, rounded up

Scoring and reference calls

2 weeks

Assumes two weeks for scoring and reference checks, plus one if more than three vendors are in demos

Planned duration before contingency

28 weeks

Includes a fixed two-week allowance for response scoring and shortlisting

Time before the RFP is issued

9 weeks

Planning estimate only. Real durations depend on approval cycles, vendor availability, holidays and the number of sites and requirements. Stages are modeled sequentially, so overlapping work such as drafting the RFP during workshops can shorten the total.

Save results:

Selection duration versus vendors in demos

Sweeps Vendors in scripted demos from 1 to 8, holding your other inputs fixed.

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How to use the calculator

Enter the weeks you expect for each stage. Set the shortlist size and demo days per vendor, then the number of days per week your selection team can realistically attend demos. The tool converts demo days to weeks, adds two fixed weeks for scoring the RFP responses and shortlisting, adds scoring and reference call time, then applies your contingency. The chart shows how total duration changes as you add vendors to the demo phase, which is the stage that stretches most.

Count weeks of elapsed time, not effort
Use real team availability for demo days
Add contingency for holidays and approvals

The stages and typical ranges

Requirements gathering usually runs four to ten weeks for a multi-site manufacturer, fewer if processes are already documented. RFP preparation takes two to four weeks. Vendors need three to five weeks to respond properly. Scripted demos take a week or two when scheduled well. Scoring and reference calls add two to three weeks. Contract negotiation and legal review commonly take four to ten weeks, and board approval a few more. Most mid-size selections therefore land between four and nine months.

Reading the result

The planned duration is the sum of the stages, and the total adds your contingency percentage. Treat the total as the date to communicate and the planned figure as the target to manage. If the result is longer than your business expects, look at the largest stage first. Often the biggest saving comes from running requirements gathering and RFP drafting in parallel, shrinking the shortlist before demos or starting legal review of draft terms during the demo phase.

Common mistakes

The most frequent error is forgetting that selection is only the first phase. Implementation planning and partner selection come afterward, and a go-live date set before selection ends is a guess. Another is underestimating negotiation: contract terms for a multi-year ERP deal and a statement of work seldom close in two weeks. Finally, planning demos for a time when key users are at month end or on holiday results in cancelled sessions and weeks of slippage.

Frequently Asked Questions

How long does ERP selection usually take?

Four to nine months is common for mid-size manufacturers, from kickoff to signed contract. Single-site, single-country projects with clear scope can finish in three to four months. Multi-country projects with formal board and procurement processes can take a year.

Can we shorten the process?

Yes. Prepare requirements before contacting vendors, run RFP drafting in parallel with workshops, limit demos to two or three vendors, pre-agree contract principles, and start legal review early. Skipping the reference calls or scripted demos saves time but increases the risk of a poor choice.

Does this include implementation time?

No. It covers selection only, up to signed contract. For implementation, use the ERP implementation timeline estimator. Remember that vendor and partner selection, planning and resource mobilization add several weeks before the formal project start.

Why does the number of demo vendors matter so much?

Each added vendor requires scripts, data preparation, one to three demo days, scoring and reference checks, and usually a second round of questions. Cutting from five vendors to three often saves a month and improves the quality of evaluation.

If you want help compressing the selection by pre-analyzing your requirements and documents privately, we can walk through how that works in your environment.

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