Detailed Assessment of Costs: A Practical Guide

Practice Guides — 2026-03-24

Step-by-step guide to detailed assessment under CPR Part 47: notice of commencement, points of dispute, replies, provisional assessment and the final hearing.

Updated 7 September 2026.

Detailed assessment determines the amount of costs payable where the parties have a right to assessment but cannot agree the sum. For a receiving party, it turns an entitlement to costs into an amount that can be recovered. For a paying party, it provides the procedure for challenging the bill.

This guide explains ordinary detailed assessment between parties in the High Court and County Court under CPR Part 47 and Practice Direction 47. It covers commencement, Points of Dispute, Replies, provisional assessment, hearings and settlement offers.

When Does Detailed Assessment Apply?

Detailed assessment is one way of determining costs. It is distinct from summary assessment and the recovery of fixed costs. Start with the costs order, the applicable costs regime and the document giving the right to assessment.

The procedure usually follows the conclusion of the proceedings, unless the court orders an immediate assessment. An appeal does not itself stay assessment: a stay must be ordered (CPR 47.1 and 47.2).

Solicitor and client assessments under the Solicitors Act 1974, publicly funded costs and costs payable out of a fund have separate requirements. The timetable below should not be applied to those procedures without identifying the relevant rules.

Negotiation can continue throughout the assessment. Offers and conduct may affect who pays the costs of that process, but the consequences depend on the applicable rule and the result obtained.

Commencing Proceedings: The Notice of Commencement

The receiving party commences detailed assessment by serving the paying party with Form N252, the Notice of Commencement, and the bill of costs. Filing a request for a hearing is a later step.

Under CPR 47.6 and PD 47 paragraph 5.2, the service documents comprise:

Form N252 and the bill of costs.

Copies of counsel's and experts' fee notes for fees claimed in the bill.

Written evidence of any other disbursement claimed which exceeds £500.

A statement giving the names and addresses for service of persons on whom the receiving party intends to serve the notice.

Where a costs management order has been made, the required breakdown of costs by phase, unless the electronic bill already provides the full breakdown. Precedent Q is the model for this document.

The notice and relevant documents must also reach any other person entitled to service under PD 47 paragraph 5.5. Establish the correct recipients and method of service before calculating the response deadline.

Time Limit for Commencing

For costs payable under a judgment or order, the ordinary deadline is three months after the judgment or order. CPR 47.7 specifies different starting points for other situations, including discontinuance, acceptance of a Part 36 offer and an assessment stayed pending an appeal.

The commencement period may be varied by agreement in writing or by the court under PD 47 paragraph 6.1. Ongoing negotiations do not themselves extend it.

Late commencement does not automatically extinguish the right to costs, and permission is not required merely to commence out of time. The court may disallow interest for delay under CPR 47.8. That is discretionary, not an automatic penalty for every late bill. The paying party can apply for an order requiring commencement by a specified date, with the consequences provided for in that order.

The Bill of Costs

The electronic bill requirements date from 6 April 2018. They apply to recoverable costs between parties for work undertaken after that date in Part 7 multi-track claims, subject to the exceptions in PD 47 paragraph 5.1 for fixed or scale costs, an unrepresented receiving party and a contrary court order.

Precedent S or another spreadsheet complying with PD 47 paragraphs 5.A1 and 5.A2 may be used. Where the electronic bill rules apply, work undertaken before the transition date may be presented in paper or electronic form; later work must comply with the electronic requirements.

The bill should identify the work, fee earner, time, rate and disbursements clearly. Follow the applicable requirements for certification, division into parts and service of the spreadsheet and any hard copy, including the Costs Office e-filing provisions where relevant.

Points of Dispute

Points of Dispute set out the paying party's objections to the bill.

For help preparing objections or responding to them, see the Points of Dispute and Replies service.

Time Limit

For ordinary domestic service, the deadline is 21 days after the date of service of the Notice of Commencement (CPR 47.9(2)). Service outside the jurisdiction requires separate attention to PD 47 paragraph 5.4.

Agree any extension in writing before the deadline. Because CPR 47.9(3) specifies a consequence for late service, the consent route must satisfy CPR 3.8(4): an extension of up to 28 days by prior written agreement, provided no hearing date is put at risk and the court has not ordered otherwise. Outside that route, seek the necessary court order promptly.

A party who serves Points of Dispute late needs the court's permission to be heard further in the assessment. Late service does, however, prevent a default costs certificate being issued if the points arrive before issue of the certificate. These are separate consequences.

Points of Dispute Format Under PD 47

PD 47 paragraph 8.2 requires Points of Dispute to be short and to the point and to follow Precedent G so far as practicable. They should:

Identify general points or matters of principle first.

Identify specific disputed items and state concisely the nature and grounds of each dispute.

Avoid repetition by identifying the other item numbers to which a point applies.

Proposing a realistic alternative figure can make an objection easier to resolve. It is useful drafting practice, rather than a substitute for stating the grounds of dispute.

The paying party must also send an open letter with the Points of Dispute stating what sum, if any, is offered in settlement of the total claim (PD 47 paragraph 8.3). A separate Part 36 offer may provide additional protection.

Replies to Points of Dispute

Replies are optional. If used, they must be served on the other parties to the assessment within 21 days after service of the Points of Dispute, subject to any applicable variation (CPR 47.13). This is a service deadline, not a requirement to file Replies at court within that period.

PD 47 paragraph 12.1 limits Replies to points of principle and concessions. They must not contain general or specific denials or standard responses. Use Precedent G whenever practicable.

A Reply should therefore address a point of principle that needs an answer or record an appropriate concession. It should not repeat the bill or provide a routine denial of every objection. Copies of any Replies accompany the later hearing request.

Default Costs Certificates

After the Points of Dispute deadline expires, the receiving party may request a default costs certificate if no Points of Dispute have been served. The request is made using Form N254 with the document giving the right to assessment and the prescribed fee.

Entitlement must still exist when the certificate is issued. Under CPR 47.9(5), Points of Dispute served by any party before issue prevent the court from issuing the certificate, even if they were late. A request already lodged does not avoid that rule.

The certificate includes an order to pay the costs to which it relates, together with the prescribed fixed assessment costs and court fee. It is not a reason to disregard late Points of Dispute already received.

Setting Aside a Default Costs Certificate

CPR 47.12 has two distinct limbs:

The court must set the certificate aside if the receiving party was not entitled to it.

In any other case, the court may set it aside or vary it if there is some good reason why the detailed assessment proceedings should continue.

An application under the second limb needs evidence. Promptness matters. Unless the court directs otherwise, the application should have the bill, certificate and draft Points of Dispute attached (PD 47 paragraph 11.2). A missed deadline or an administrative mistake does not itself guarantee relief.

Provisional Assessment

Requesting the Assessment

The receiving party must request a detailed assessment hearing within three months after the end of the period for commencing assessment, subject to a valid variation. The deadline runs from the end of that period, rather than from the date the bill was actually served (CPR 47.14 and PD 47 paragraph 13.1).

Use Form N258 with the documents required by PD 47 paragraph 13.2, including the bill, document giving the right to assessment, relevant orders, Points of Dispute and any Replies. The N258 procedure also applies when requesting provisional assessment, with the additional requirements in paragraph 14.3, including the relevant offers and a statement of the costs claimed for the assessment.

How Provisional Assessment Works

For qualifying Part 47 assessments in the High Court and County Court, the provisional procedure applies where the costs claimed do not exceed £75,000 (CPR 47.15 and PD 47 paragraph 14.1). The court may direct an ordinary hearing if it considers the case unsuitable. A claim governed by fixed costs does not become a provisional assessment simply because its value is below the threshold.

The court assesses the bill without the parties attending, using the bill, supporting papers and the contentions in Precedent G. There is no routine entitlement to add separate written submissions on the merits; comply with the prescribed procedure and any court directions.

After receiving the assessed Precedent G, the parties must seek to agree the resulting total within 14 days. If they cannot agree the arithmetic, they must refer the dispute to the court for determination on written submissions (PD 47 paragraph 14.4).

The Costs Cap

Where the proceedings do not go beyond provisional assessment, CPR 47.15(5) caps the costs awarded to any party for the proceedings at £1,500, plus VAT on those costs and the court fees paid by that party. Costs of drafting the bill are excluded from that cap.

The rule contains no general “exceptional circumstances” escape from this cap. An entitlement to indemnity costs under Part 36 should not be treated as automatically removing it.

Challenging the Provisional Assessment

A party seeking an oral hearing must file and serve a written request within 21 days of receiving the court's notice. The request must identify the items for review and give a time estimate. Without a timely request, the provisional assessment binds the parties, save in exceptional circumstances (CPR 47.15(7) and (8)).

The requesting party pays the costs of and incidental to the oral hearing unless it achieves an adjustment in its favour of at least 20% of the sum provisionally assessed, or the court otherwise orders. The comparison is against the whole sum provisionally assessed, not just the items challenged. Conduct and offers are relevant to the court's discretion under PD 47 paragraph 14.5.

Crossing the 20% threshold removes the usual adverse costs rule; it does not guarantee an order recovering all the requesting party's costs. Assess the likely adjustment and the hearing costs before making the request.

Oral Assessment Hearing

Assessments outside the provisional procedure will ordinarily require a hearing, subject to the court's directions. There are exceptions: where the only dispute concerns disbursements, PD 47 paragraph 13.5 ordinarily provides for determination on the papers unless the court orders otherwise.

What Happens at the Hearing

The court considers the disputed items and the parties' submissions, allowing, reducing or disallowing the sums claimed. At an ordinary detailed assessment hearing, only items specified in the Points of Dispute may be raised unless the court permits otherwise (CPR 47.14(6)).

The assessment basis matters. Under CPR 44.3, costs must be reasonably incurred and reasonable in amount on either basis. On the standard basis, they must also be proportionate and doubts are resolved in favour of the paying party. On the indemnity basis, doubts about reasonableness are resolved in favour of the receiving party; the standard basis proportionality test does not apply.

Where a costs management order has been made, CPR 3.18 governs assessment of budgeted costs on the standard basis, including the requirement for good reason to depart from approved or agreed budgeted costs. Identify the relevant phases and distinguish budgeted from incurred costs.

Preparation for the Hearing

Narrow the issues, record agreed figures and have the supporting papers and any relevant authorities ready. Follow the court's directions for lodging documents. A clear account of the remaining disputes helps the court use hearing time effectively.

After an ordinary detailed assessment hearing, complete the bill to show the figures agreed or allowed and file it within 14 days after the end of the hearing, together with the required supporting material for the final certificate (CPR 47.17 and PD 47 paragraph 16).

Interim Costs Certificates and Payments on Account

Payments on Account

Where the court orders costs subject to detailed assessment, CPR 44.2(8) requires a reasonable sum on account unless there is good reason not to order one. This is commonly addressed when the costs order is made.

There is no prescribed percentage of the bill or budget. Support the proposed sum by reference to likely recovery, the basis of assessment, the budget where relevant and the substantial disputes.

Interim Costs Certificates

The court's power to issue an interim certificate under CPR 47.16 arises after the receiving party has filed the request for a detailed assessment hearing. It may certify a sum it considers appropriate, not merely amounts already agreed. An application is made under Part 23 (PD 47 paragraph 15).

This is distinct from a payment on account under CPR 44.2(8) and from a certificate for an agreed amount under CPR 47.10. Select the route that is available at the stage reached.

Offers to Settle Costs Proceedings

Part 36 Offers

Part 36 applies with the modifications in CPR 47.20. The receiving party is treated as claimant, the paying party as defendant, and detailed assessment as an independent claim.

A valid offer must meet CPR 36.5, including its requirements for writing, reference to Part 36, scope and the relevant period. State clearly the treatment of VAT, bill preparation and interest. A figure described simply as a “Part 36 offer” is not enough if the requirements are unmet.

If the receiving party obtains a result at least as advantageous as its own effective offer, CPR 36.17 ordinarily provides for indemnity costs of the assessment from expiry of the relevant period, the prescribed enhanced interest and an additional amount, subject to the rule's limits, exceptions and the test of whether those consequences would be unjust. This does not retrospectively change the basis of the underlying litigation costs.

If the receiving party fails to beat an effective paying party's offer, the ordinary consequence is that the paying party recovers its assessment costs from expiry of the relevant period, with interest on those costs, unless unjust. The provisional assessment cap must still be considered where applicable.

Calderbank Offers

An offer made “without prejudice save as to costs” can be considered when the court decides the costs of the assessment. It does not attract the automatic consequences of a compliant Part 36 offer.

Value an offer against the likely assessment outcome and the costs of continuing. There is no standard percentage discount that protects every receiving party. Keep the offer's scope and treatment of assessment costs clear.

Costs of the Assessment

The general rule under CPR 47.20 is that the receiving party is entitled to the costs of detailed assessment, subject to contrary legislation, rules, practice directions or a court order.

In deciding whether to depart from that rule, the court considers conduct, the amount by which the bill has been reduced and whether it was reasonable to claim or dispute a particular item. Offers may also affect the result. A substantial reduction is relevant but does not automatically transfer all assessment costs to the paying party.

Common Tactical Considerations

For Receiving Parties

Serve a clear, supportable bill and the prescribed commencement documents within the applicable period.

Diary the separate N258 deadline by reference to the end of the commencement period.

Make a realistic offer based on likely recovery.

Consider a payment on account or, once N258 has been filed, an interim certificate under CPR 47.16.

Use Replies within their permitted scope and narrow the issues before a hearing.

For Paying Parties

Serve concise Points of Dispute on time and send the required open settlement letter.

Obtain any permitted extension by prior written agreement, with the 28-day limit and hearing safeguard in mind.

If already late, act promptly: service before a default certificate is issued prevents issue, but permission to be heard further remains necessary.

Make a properly valued settlement offer.

Before requesting an oral review, consider the 20% whole-assessment test, the court's discretion and the likely hearing costs.

Detailed Assessment Time Limits at a Glance

This timetable concerns ordinary inter partes assessment with domestic service. Apply the actual order, the correct CPR 47.7 trigger, the rules for calculating time and any valid variation.

Step

Ordinary deadline or starting point

Serve N252, the bill and prescribed documents

Within three months after the judgment or order; CPR 47.7 specifies other triggers where applicable.

Serve Points of Dispute

21 days after service of N252. Any consent extension must meet CPR 3.8(4), including prior written agreement, the 28-day limit and no risk to a hearing date.

Serve optional Replies

21 days after service of Points of Dispute, subject to any applicable variation.

File N258 and the required documents

Within three months after expiry of the period for commencing assessment.

Agree the arithmetic after provisional assessment

Within 14 days after receipt of the assessed Precedent G; refer any unresolved arithmetic dispute to the court.

Request an oral hearing after provisional assessment

File and serve within 21 days after receipt of the court's notice, identifying the items and giving a time estimate.

File the completed bill after an ordinary assessment hearing

Within 14 days after the end of the hearing.

Listing times vary by court and case. Settlement may resolve the assessment before any hearing is needed.

Key Takeaways

Commence by service of N252 and the bill with the prescribed documents. N258 is a separate, later request.

Use the correct bill format. The electronic requirements concern qualifying work after 6 April 2018 and have defined exceptions.

Distinguish service deadlines, consent extensions and applications for court relief.

For provisional assessment, account for the £1,500 cap, with bill drafting excluded and VAT and court fees additional. An oral review has a separate costs rule, including the 20% test and the court's discretion.

Prepare a realistic bill or focused objections, make informed offers and keep the issues proportionate to the sums at stake.

Need Help With a Detailed Assessment?

Mackenzie Costs assists receiving and paying parties with bills, objections, negotiations and hearings. The detailed assessment service explains the available support.

For an initial review, provide the costs order, bill or time ledger, any Points of Dispute and Replies, relevant offers and the current deadline. The scope, timetable and fee basis are agreed before substantive work begins.

Contact Mackenzie Costs to discuss a detailed assessment.

Related Specialist Support

Costs Budgeting and Detailed Assessment: Precedent H, dispute documents, negotiations and assessment strategy.
Bills of Costs: Clear, defensible traditional and electronic bills prepared for recovery.
Costs Lawyer Support: Direct help with costs procedure, strategy, drafting and advocacy.