Guide to Cost Estimation Guide to Cost Estimation

The Guide to Cost Estimation is part of Auckland Transport’s Enterprise Project and Programme Management Framework suite of guides.

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About the guide

The guide provides a structured cost estimation framework and standardised documentation for a consistent approach to the preparation and verification of Auckland Transport (AT) cost estimates.

The guide enables accurate and robust cost estimates for transport related infrastructure project funding applications from design through to physical work delivery and is aligned with the industry recognised Waka Kotahi SM014 standard. 

Download the guide

Download the Guide to Cost Estimation (PDF 2.2MB, 36 pages)


A downloadable Excel workbook template that presents the cost estimate information in a consistent format and language for use by the estimator.

A downloadable Excel workbook template for recording the outcome of the ‘Input Review Meeting’ under clause 6.3.1 of the guide. This records all the inputs used to formulate and substantiate the estimate.

A downloadable Excel workbook template for use by the estimator responsible for peer reviewing the cost estimate. It includes a checklist of all the components essential to a fully considered estimate prepared in accordance with the guide.

Additional guidance

AT Admin Fee

The AT Admin Fee is added to cost estimates where funding is being sought from Waka Kotahi NZ Transport Agency (Waka Kotahi). It applies to most cost estimates, with only a few exceptions. By arrangement with Waka Kotahi, it contributes to Auckland Transport’s (AT) overhead costs of running the organisation. Using NZS3910 language, consider this to be similar to Contractor 'Off-site Overheads’ (no profit). It is not the same provision as the ‘AT Managed Costs’, which are related to the direct costs of delivering the scheme/project at the various phases. In NZS3910 terms, consider this to be equivalent to Contractor ‘On-site Overheads’. If there are any concerns about when it is to be used, please consult with your AT Estimate Owner.

Waka Kotahi and KiwiRail managed costs

Provision for Waka Kotahi and KiwiRail managed costs depends on the scope of the project and its direct impact on corridors controlled by those authorities. Essentially though, costs need to be allowed for any works interfacing with the state highway network or rail corridor i.e., joining onto, passing under or over, where it’s most likely they need to expend management effort at the various phases to develop and deliver the project.

Additionally, other agencies that may be impacted, such as utility companies, need to be provided for as well.

The best approach is to determine up front with them as far as possible, whether they consider their involvement comes at a cost or not at each of the estimate phases. If in doubt, allow for it.

What to allow for these managed costs

How much to allow for these managed costs is always a tricky question as each situation is different. Unless a specific and well considered estimate can be undertaken, a percentage ratio of the base estimate of physical works (subtotal D.2 on the Estimate Summary Sheet, Appendix A) is the most pragmatic approach. A reasonable percentage at each estimate phase would sit between the AT Managed Costs and Consultancy Fees allowances, tending closer to the former being reflective of an owner participant effort.

The exception to this is under D.1, KiwiRail (KR) costs during the Implementation Phase, where KR management and physical works costs can be calculated with more certainty to incorporate the cost elements below (and any other KR costs as may be identified and appropriate).

  • Block Of Line costs (BOL) including potentially buses replacing passenger rail, alternative freight transportation costs incurred by KR.
  • Overhead Line Equipment (OLE) de-energized, removed and reinstated as may be applicable to the scope.
  • KR safety stand-over/protection costs.
  • Corridor access permit costs.
  • KR management costs covering all the above.

These can be minimised by incorporating any critical works impacting the KR and AT Metro operations into planned KR annual new year maintenance BOLs, for example. Essentially, where operations are always suspended for extended periods or where costs can be split amongst several Contractors (coordinated closely with KR) undertaking booked/planned works simultaneously at various locations under one BOL.

See Appendix A – Cost Estimate Calculation and Summary Workbook.

Use of cost ratios by category, spanning the three estimate phases

AT has researched project out-turn cost data from 2011 to 2020, over a range of project values and types, to identify the averaged ratios provided. These are a robust starting point. In lieu of any other calculation, these ratios shall be applied, but weighed up against the scope and risk of the intended physical works to either slightly raise or lower the ratio.

The AT Managed Cost ratios are a blend of a wide range of internal AT resources contributing to the project, as some are not readily apparent ‘up-front’ in performing a formal estimate. These costs are very difficult to estimate, even internally within AT, so the ratios provided are ‘best for project’. Only AT knows what AT costs.

See Figure 2/Table 2, page 17 and Table 3, page 18 in the guide.

External consultant access to ‘Section 5 Referenced Documents’ of the guide

The links to other AT resources listed at the back of the guide are for internal use, so only work for AT users or contracted external consultants with access to work in the AT environment. If you are unable to view these documents, please speak to your Project Sponsor i.e., the Estimate Owner in accordance with the guide definition, who can request access to the AT environment for you via the internal AT Assist system. Should you continue to have access difficulties, thereafter, please send a request via for assistance.


In addition to the Guide to Cost Estimation, AT will be looking to make more guides available to external consultants, where they are deemed a required tool of trade to deliver related consultant services. So, watch the AT website for future additions.