Formal vs Casual Ways to Say ‘Let me know’

When you need someone to update you, the phrase “Let me know” is a natural choice. However, the same words can sound too direct in a formal email or too stiff in a casual text. The direct answer is this: use “Please keep me informed” or “I would appreciate an update” for formal situations, and use “Keep me posted” or “Just tell me” for casual conversations. This guide will help you choose the right version for every context, whether you are writing to a client, a colleague, a friend, or a family member.

Quick Answer: Which Version Should You Use?

If you are unsure, follow this simple rule: when in doubt about formality, match the tone of the person you are writing to. For a boss or a customer, lean formal. For a teammate or a friend, lean casual. Below is a quick reference to help you decide.

• Formal (emails, reports, official requests): “Please keep me informed,” “I would appreciate an update,” “Kindly advise.”
• Casual (texts, chats, friendly conversations): “Keep me posted,” “Just give me a heads up,” “Tell me how it goes.”
• Neutral (works well in most situations): “Let me know when you have an update,” “Feel free to update me.”

Comparison Table: Formal vs Casual Versions

Formal Ways to Say ‘Let me know’

Formal language is about respect, clarity, and distance. You use it when you do not know someone well, when you are in a position of less authority, or when the topic is serious. Here are the most useful formal alternatives.

1. Please keep me informed

This is a standard, polite request. It works in almost any professional email. It shows you expect updates without sounding demanding.

Example: “Please keep me informed of any progress on the project.”

2. I would appreciate an update

This phrase adds a layer of politeness. It implies that the update is a favor, not an obligation.

Example: “I would appreciate an update once the team has reviewed the proposal.”

3. Kindly advise

Short and formal. “Kindly advise” is common in business correspondence, especially when you need a decision or next step.

Example: “Kindly advise on the preferred delivery date.”

4. I look forward to your update

Use this as a closing line. It is confident and polite, and it sets a positive expectation.

Example: “Thank you for your time. I look forward to your update.”

5. Please notify me of any changes

This is direct but respectful. It works well for official notices or when you need to be alerted about specific changes.

Example: “Please notify me of any changes to the schedule.”

Casual Ways to Say ‘Let me know’

Casual language is for people you know well or for situations where you want to sound friendly and relaxed. It is shorter and often uses phrasal verbs.

1. Keep me posted

This is the most common casual alternative. It is friendly and natural.

Example: “Keep me posted on how the interview goes.”

2. Just give me a heads up

Use this when you want a quick warning or early information. It is very informal.

Example: “Just give me a heads up if you are going to be late.”

3. Tell me how it goes

This is perfect for after an event or meeting. It shows interest without pressure.

Example: “Tell me how it goes with the new client.”

4. Let me know what’s next

Simple and direct. It works in texts or quick chats.

Example: “Let me know what’s next after the meeting.”

5. Can’t wait to hear

This adds enthusiasm. Use it with friends or close colleagues when you are excited about the outcome.

Example: “Can’t wait to hear how your presentation went.”

Natural Examples in Context

Seeing these phrases in real situations helps you understand when to use each one. Below are examples for different scenarios.

Formal Email Example

Subject: Update on Q3 Report

Dear Ms. Chen,

Thank you for your work on the Q3 report. Please keep me informed of any revisions before the final submission. I would appreciate an update by Friday if possible.

Best regards,
James

Casual Text Example

Message: Hey, keep me posted on the game tonight. Just give me a heads up if you are running late. Tell me how it goes!

Workplace Speaking Example

Manager to team member (formal): “Please keep me informed about the client’s feedback.”

Colleague to colleague (casual): “Let me know what’s next after the call.”

Common Mistakes

Even advanced learners make these errors. Here are the most frequent ones and how to fix them.

Mistake 1: Using “Let me know” in very formal writing

Incorrect: “Let me know if you have any questions.” (in a formal job application email)

Correct: “Please do not hesitate to contact me if you have any questions.”

Mistake 2: Using “Kindly advise” with friends

Incorrect: “Kindly advise on what time we should meet.” (to a close friend)

Correct: “Just tell me what time works for you.”

Mistake 3: Mixing formal and casual tone in one sentence

Incorrect: “I would appreciate an update, and keep me posted.”

Correct: Choose one tone. Either “I would appreciate an update” (formal) or “Keep me posted” (casual).

Mistake 4: Overusing “Please advise”

This phrase is common but can sound robotic if used too often. Vary your language with “I would appreciate your guidance” or “Please let me know your thoughts.”

Better Alternatives for Specific Situations

Sometimes you need more than just a general phrase. Here are alternatives for specific contexts.

When you need a decision

• Formal: “Please let me know your decision by end of day.”
• Casual: “Just tell me yes or no when you can.”

When you need confirmation

• Formal: “Kindly confirm your availability for the meeting.”
• Casual: “Confirm if you can make it.”

When you need feedback

• Formal: “I would appreciate your feedback on the draft.”
• Casual: “Let me know what you think.”

Mini Practice: Choose the Right Version

Test your understanding. Choose the best phrase for each situation. Answers are below.

Question 1: You are writing to your manager about a project deadline. What is the best phrase?

A) Keep me posted
B) Please keep me informed of any changes to the deadline
C) Just tell me when

Question 2: You are texting a friend about their job interview. What is the best phrase?

A) I would appreciate an update on the interview outcome
B) Kindly advise on the interview results
C) Keep me posted on how it goes

Question 3: You are emailing a new client about a proposal. What is the best phrase?

A) Let me know what’s next
B) Please let me know your thoughts on the proposal at your earliest convenience
C) Tell me how it goes

Question 4: You are in a team meeting and want a quick update from a colleague. What is the best phrase?

A) I look forward to your update
B) Kindly advise on the status
C) Let me know what’s next after the meeting

Answers: 1-B, 2-C, 3-B, 4-C

Frequently Asked Questions

1. Can I use “Let me know” in a formal email?

Yes, but only if you add polite words. For example, “Please let me know if you have any questions” is acceptable in semi-formal emails. For very formal situations, use “Please keep me informed” or “I would appreciate an update.”

2. Is “Keep me posted” too casual for work?

It depends on your workplace culture. In many modern offices, “Keep me posted” is fine with colleagues you work with regularly. Avoid it in emails to senior executives or external clients unless you know them well.

3. What is the most neutral way to ask for an update?

“Let me know when you have an update” is neutral and works in most situations. It is not too formal and not too casual. You can use it in emails, messages, and even in person.

4. How do I ask for an update without sounding impatient?

Add a polite opener. For example, “When you have a moment, please let me know the status” or “No rush, but I would appreciate an update when you can.” This shows respect for the other person’s time.

Final Tips for English Learners

Choosing between formal and casual language is about understanding your audience. When you are unsure, start with a neutral or slightly formal phrase. You can always adjust later if the other person responds casually. Practice by writing one formal email and one casual message each day. Over time, the right phrase will feel natural.

For more help with polite everyday phrases, visit our Polite Everyday Phrases section. If you need professional email alternatives, check out our Professional Email Alternatives category. For workplace speaking, see our Workplace Speaking Phrases guide. And for more comparisons like this one, explore our Formal and Casual Versions page.

If you have questions about this guide, please contact us. We are happy to help you improve your English.