Block Billing in Legal Invoices: A Complete Guide

Legal billing is one of the most important parts of law firm management. It is how lawyers get paid, but it is also how they communicate with their clients about the work they did. Clear billing shows professionalism, builds trust, and avoids disputes.

One billing practice that often causes problems is block billing. Clients often reject invoices that use block billing, and law firms lose money when invoices are not approved or are discounted. In this guide, we will explain everything about block billing in detail. Let’s get started.

What Is Block Billing?

Block billing is a method of recording work where multiple tasks are combined into one single line on an invoice or timesheet. Instead of writing separate entries for each task, all the tasks done in a certain time period are grouped together and the total time is added.

Block billing is used when lawyers or staff do many small tasks throughout the day and want to summarize them in a single entry. It is meant to save time, but it can make it very difficult for clients to see what exactly was done and how long each part took.

Think about it like trying to describe a whole day’s work to someone in one sentence. You can do it quickly, but it leaves out all the important details. Your client, who is paying for your time, will not see those details.

Example of Block Billing

Notice that 6 hours covers four different tasks. The client cannot see how much time was spent on each task. They only see a total number of hours for multiple unrelated activities. This makes it hard for the client to understand what exactly they are paying for.

Why It’s Called “Block Billing”?

The term comes from the idea of putting several tasks into a single “block” of time. Think of it like putting different bricks together in one pile. The problem is that the client sees the pile but cannot see each brick separately.

While block billing may seem simpler for the law firm, it reduces transparency, makes invoices harder to read, and increases the chances of disputes or questions from clients. If you are reading this, imagine being the client looking at a long list of blocks with no details. It can feel confusing and even frustrating. That is why understanding this concept is critical for anyone responsible for legal billing.

How Law Firms Use Block Billing

Many law firms still use block billing because it is fast and convenient. Writing multiple line items for each small task takes time, and lawyers often have many tasks to complete in one day. Summarizing work in a block makes billing easier, but it comes at the cost of clarity.

Some common reasons law firms use block billing:

1. Saves Time for Lawyers: Lawyers are busy with client work, court appearances, and meetings. If they must write every small task separately, it takes a lot of time. A single block entry can save minutes or even hours each week. This time savings might seem small on a daily basis, but over weeks and months it adds up significantly.

2. Easier for Staff: Billing clerks or assistants can summarize a day’s work in a few lines instead of dozens of separate entries. This reduces paperwork and administrative work, and it feels like the easiest path when managing large teams or many matters at once.

3. Old Practice: Many law firms have used this method for decades. Changing habits can be difficult because it requires lawyers and staff to track time more carefully. If you have been in a law firm for years, you may recognize this as something you have done yourself without even thinking about it.

4. Aligned with Hourly Billing: Law firms often focus on recording hours rather than task-level detail. The total time matters more than which tasks were completed. This is why, historically, block billing persisted, it feels like it gets the job done quickly.

You might recall a 2023 study that revealed 94% of law firms still rely mainly on hourly billing. To learn more about hourly billing, or if you are interested in diving into the ins and outs of hourly billing in our blog post.

Even though it saves time, block billing can create confusion and disputes when clients do not understand the invoice. If you are responsible for billing, it is important to see that convenience for the firm can sometimes come at a cost for clarity and client satisfaction.

Why Clients Reject Block Billing?

Clients, especially corporate clients and government agencies, want clear, itemized invoices. They want to know exactly what they are paying for. Block billing prevents them from understanding the work done.

Clients reject block billing for several reasons. As someone reading this, think about what it would feel like if you were the client: would you pay for work that you cannot see in detail? Most likely, the answer is no.

• Lack of Transparency

A block-billed invoice might say:

Worked on multiple tasks - 7.5 hours

This tells the client nothing about what specific tasks were done, how long each task took, or whether the time was reasonable. Clients are often required to report legal costs internally. When they cannot justify the hours spent, they are more likely to dispute the invoice.

Transparency is critical because clients want to see that the time they are paying for was spent efficiently and effectively. Without it, trust can be damaged, and clients may hesitate to approve future invoices.

• Hard to Justify Costs Internally

Many clients must explain legal bills to finance teams, auditors, or managers. A vague block billing entry is hard to defend. The client may have to ask the law firm for additional explanations, which delays payment and creates frustration for both sides.

For corporate clients, every invoice is part of a budgeting and approval process. If an entry is unclear, it may be rejected outright or require adjustments, which slows down revenue collection. This is especially true when multiple lawyers are working on a single matter, because the client may need a full breakdown to understand the time spent by each person.

• High Invoice Rejection Rates

Studies show up to 30% of invoices can be rejected due to vague or non-compliant billing. Rejections cost law firms extra time and may also delay cash flow.

Many large corporate clients now use electronic billing systems (e-billing). These systems have rules for how lawyers must record time. Block billing entries often fail to meet the required standards.

Even minor issues in task descriptions can result in rejected invoices, which means lawyers must spend more time fixing errors instead of focusing on billable work.

When reading this, imagine being the billing clerk having to go back and correct multiple invoices for multiple lawyers – it can be frustrating and inefficient.

• Perceived Inefficiency

Clients, according to a study in 2025, expect value for high hourly rates. Senior partners at large law firms may charge $2,000–$3,000 per hour.

When clients see block billing entries, they often cannot tell if the work was done efficiently. They may assume time was wasted or tasks were grouped unnecessarily. Even if the work was reasonable, the perception of inefficiency can hurt trust.

• Impacts on Trust

Transparent billing builds trust. When clients cannot see exactly what they are paying for, they may:

• Question the value of services

• Negotiate discounts

• Consider other law firms for future work

Trust is critical for long-term client relationships. Losing it can have financial and reputational consequences. For anyone managing invoices, thinking about the client’s perspective helps prevent mistakes before they happen.

Financial Implications of Block Billing

Block billing may seem harmless at first because it saves time when entering hours. But in reality, it can affect your law firm’s revenue and efficiency in several ways, and this is something everyone in billing or management should take seriously. Understanding these implications can help law firms make better decisions about how to track and bill time.

• Lost Billable Time

Block billing often leads to small tasks being unrecorded or undervalued. For example, a lawyer may spend 15 minutes reviewing emails, 10 minutes on a phone call, and 20 minutes reviewing a document. If these are all combined into one block entry, the client cannot see the breakdown. In some cases, the client may even question whether all that time was necessary.

Studies show 10–15% of billable hours can be lost due to inefficient time tracking and block billing. Think about this: if a lawyer works 1,800 hours in a year and 10% of those hours are lost or unbilled because of block entries, that is 180 hours of lost revenue per lawyer per year. Multiplied across a firm with ten lawyers, that could be 1,800 hours, which is a huge amount of money left uncollected.

• Fee Write-Downs

Clients often request discounts or write-downs when invoices are unclear. When they cannot understand the time spent, they may feel the firm is overbilling. This leads to a lower realization rate, which is the percentage of fees billed that the firm actually collects.

For example, a firm may bill $100,000 in a month, but because some invoices are rejected or require adjustments, they only collect $85,000. That is $15,000 of revenue lost simply because the invoice lacked detail.

• Extra Administrative Work

When invoices are rejected due to block billing, lawyers and billing staff must spend extra time fixing them. This involves:

• Breaking down blocks into detailed entries
• Explaining tasks to the client
• Resubmitting corrected invoices

This extra work is non-billable, meaning the firm is spending time without generating income. For law firms, time spent correcting invoices is time that could have been spent on billable client work. Over time, these small corrections add up and impact the firm’s efficiency.

Think of it this way: the time “saved” by using block billing often costs more than it saves in the long run.

Step-by-Step Conversion: Block Billing to Itemized Billing

If you or your staff are still using block billing, it’s important to know how to convert it into itemized billing. The process is straightforward but requires attention to detail. Let’s go step by step using a practical example.

Imagine a scenario in which a lawyer worked on discovery tasks on January 10, 2026.

Block Billing Entry:

Notice that the total hours are correct, but the client cannot see how time was spent on each task.

Step 1: Break Down Tasks by Time

Breaking down tasks provides transparency and shows the client exactly where their money is going.

Step 2: Prepare Itemized Invoice

Now, the client can immediately understand the breakdown of hours. They can see that 2 hours went to reviewing documents, 1 hour to calls, and 2.5 hours to drafting plans.

Tip for billing staff: Always double-check that the total hours in the itemized invoice match the total hours previously recorded in the block entry. This ensures accuracy and avoids disputes.

Visual Charts and Dummy Invoices

Visuals make it easier for everyone to understand the difference between block and itemized billing. Here are two examples:

Hours Breakdown

Notice how the same total time is now clearly distributed across tasks. Clients can see exactly what they are paying for.

The clarity score shows how easy it is for clients to understand invoices. Block billing is often confusing, while itemized billing provides transparency and trust.

Extra Tip: You can even create a small note in your invoice explaining tasks that are complex or involve multiple team members. This extra detail builds client confidence and reduces follow-up questions.

Are There Some Best Practices Or Alternatives

Block billing is not always “bad,” but it’s important to consider alternatives that make billing clear, accurate, and professional. The following are some practices that can be followed:

1. Itemized Billing: Record each task separately. This is the most transparent and widely accepted method. Clients appreciate seeing exactly what they are paying for.

2. Task or Phase-Based Billing: Sometimes, you can group tasks into phases (e.g., “Discovery Phase” or “Drafting Phase”), but still list individual tasks under that phase. This method keeps things organized without losing transparency.

3. Matter Budgeting: Provide clients with an estimated cost for a case or project before starting work. When clients know in advance what to expect, they are less likely to dispute invoices.

4. Use Billing Software: Many law firms now use software that automatically tracks time, ensures compliance with client billing rules, and generates professional invoices. This reduces human error and saves administrative time.

Tip for lawyers and billing staff: Always include short explanatory notes for complex tasks. Even one extra sentence like “Reviewed 50 pages of documents for relevancy and accuracy” can help the client understand your work and avoid confusion.

Conclusion

Block billing may save time for lawyers, but it often creates more problems than it solves:

• Clients cannot see task-level details
• Invoice rejection rates increase
• Realization rates drop
• Clients may question the value of legal services

Switching to itemized, detailed, and transparent billing can build client trust, reduce disputes and write-downs, improve law firm revenue and efficiency, and help staff and lawyers avoid unnecessary back-and-forth with clients. When it comes to legal billing, clarity, honesty, and detailed explanations are more important than convenience.

If you are responsible for billing, this guide should give you the confidence to review current invoices, convert block entries, and implement best practices that will benefit both your clients and your law firm.

For more details on block billing or if you need some guidance on how to implement the best practices of block billing in your business, do not hesitate to reach out to us today.