X (Twitter) Tweet Virality and Amplification Calculator

The calculator needs three counts from one post that has already run: impressions, reposts and quotes. Counts for your typical post turn the result into a comparison.

1. Open the analytics of the post and copy its impressions, reposts and quotes.
2. List the impressions of your last 10 to 20 posts in order and take the middle value. Do the same for reposts plus quotes. These are your typical post.
3. Add your follower count at the time of posting.
4. Add impressions from non-followers only when your analytics shows that split.

Tweet virality is the spread of a post beyond the followers of its author, through people passing it on. X has no metric called virality and publishes no virality score. This page measures the part of spread that X does count: reposts and quotes against impressions.

X Help, read on October 3, 2026, defines a repost as a post you share publicly with your followers. A quote is a repost with your own comment added. Each one puts the original post in front of another account's followers, which is why the two counts together describe amplification.

Why This Page Gives No Probability

A probability needs a tested model and a base rate. X publishes neither. X Help says only that posts from accounts you do not follow are selected with a variety of signals, including how popular a post is and how people in your network interact with it. No weights, thresholds or odds are given.

Any tool that prints "32% chance of going viral" has invented that number. This page reports what a finished post did, measured against your own usual post. Speed of engagement over time is a separate question, covered by the X engagement velocity calculator.

1. The tool adds reposts and quotes, divides by impressions and multiplies by 1,000.
2. It runs the same formula on your typical post.
3. It divides the first rate by the second to get a multiple.
4. It divides this post's impressions by your typical impressions.
5. It divides impressions by followers.
6. It divides non-follower impressions by all impressions, and quotes by all shares, for two percents.

A multiple of 1.00 means the post was shared at your usual rate. A multiple of 2.50 means it was shared at two and a half times that rate.

Example values only. A post collected 48,000 impressions, 420 reposts and 60 quotes. The author had 12,000 followers, and 30,000 of the impressions came from non-followers. The author's typical post gets 6,000 impressions and 24 reposts plus quotes.

• Amplification rate = (420 + 60) / 48,000 x 1,000 = 10.0 per 1,000 impressions.
• Typical post = 24 / 6,000 x 1,000 = 4.0 per 1,000 impressions.
• Amplification vs typical = 10.0 / 4.0 = 2.50 x.
• Impressions vs typical = 48,000 / 6,000 = 8.00 x.
• Impressions per follower = 48,000 / 12,000 = 4.00.
• Non-follower share = 30,000 / 48,000 x 100 = 62.5%.
• Quote share = 60 / 480 x 100 = 12.5%.

The post was seen 8 times as often as usual and shared at 2.5 times the usual rate. Most impressions came from outside the follower list. Those are facts about one finished post. They do not say what the next post will do.

When You Take the Reading

Impressions and shares keep arriving after you post. A reading at 2 hours and a reading at 7 days differ. Compare posts at the same age. To study how a post fades, see the tweet lifespan calculator.

Reposts and Quotes Are Separate Counts

The X developer documentation states that the repost count does not include quote posts. Enter both, or the rate comes out too low.

How Impressions Are Counted

An impression is a time the post appeared on a screen. X states the count is not unique, so one person viewing twice adds two. Heavy repeat viewing lowers the rate.

Promoted Posts

The X developer documentation splits metrics into organic and promoted, and paid impressions add to the public total. It also notes that quote counts are always organic. Measure promoted posts apart from organic ones.

The Mean Hides the Typical Post

Five posts with 3, 4, 5, 6 and 60 shares have a mean of 15.6 and a middle value of 5. The middle value, or median, describes your usual post better.

An amplification rate reports what a post did, and a virality score claims to say what a post will do. Only the first can be checked against your analytics.

To isolate what quotes added to a post, use the quote post impact calculator.

After a Post Takes Off

Check whether the post was shared more per impression, or only shown more. An 8.00 x impressions multiple with a 1.00 x amplification multiple means wider display at your usual share rate.

Reviewing a Month of Posts

Run each post and save the results. Sort by amplification vs typical to find the posts readers chose to pass on.

Comparing Formats

Take the typical post for threads and for single posts separately. The rate per 1,000 impressions removes the difference in reach.

Reporting to a Client

State the rate, the multiple and the age of the post at the reading. For rates that include likes, replies and clicks, use the X engagement rate calculator.

1. Believing a Viral Probability

X publishes no model, weights or base rates. A percent chance shown by a tool is made up.

2. Reading Impressions as Virality

A post can be shown widely and passed on rarely. Check both multiples.

3. Using the Mean as the Typical Post

One large post pulls the mean far above your usual result. Use the middle value.

4. Comparing Posts of Different Ages

A week-old post has had more time to collect shares than a post from this morning.

5. Buying or Trading Reposts

The X Authenticity policy prohibits coordinating to exchange engagement and paying others to inflate metrics such as reposts and views. Enforcement can include restricted reach and suspension.

6. Judging a Small Post by Its Rate

4 shares on 400 impressions is 10.0 per 1,000, the same rate as 48 shares on 4,800. Small counts swing widely, so read the raw numbers too.

Each figure is exact for the counts you enter. The figures describe one finished post, and they do not forecast any other post.

The non-follower field depends on your analytics showing that split. Leave it blank when it does not. The other results are unaffected.

No. X publishes no model, weights or base rates, so no honest probability can be computed. This calculator measures how far a finished post was shared.

Measure amplification. Add reposts and quotes, divide by impressions and multiply by 1,000. Then divide by the same rate for your typical post to see how unusual the post was.

X publishes no good or average rate. Rates differ by topic, format and audience. Compare each post with your own typical post.

No official threshold exists. X defines no impression count at which a post becomes viral. A multiple of your own typical impressions is a clearer measure.

No. X reports impressions, likes, replies, reposts, quotes and bookmarks. It publishes no virality score.

No. The X developer documentation states that the repost count does not include quote posts. Enter the two counts in separate fields.

Your typical post is the middle value of your recent posts. List the impressions of your last 10 to 20 posts in order and pick the middle one. Do the same for reposts plus quotes.

X Help says it selects them with a variety of signals, including how popular a post is and how people in your network interact with it. It publishes no weights.

No. The X Authenticity policy prohibits coordinating to exchange engagement and compensating others to inflate metrics such as reposts, likes and views. Penalties include restricted reach and suspension.

No. The maths runs in your browser and nothing is sent to us. Save keeps a result only in this browser.

• X API documentation: Metrics (X developer documentation, read 2026-10-03; definitions of impressions, reposts and quotes; the repost count excludes quotes; quotes are always organic).
• How to Repost (X Help Center, read 2026-10-03; what a repost and a quote are).
• About your For you timeline on X (X Help Center, read 2026-10-03; posts from accounts you do not follow are selected with a variety of signals; no weights are published).
• View counts (X Help Center, read 2026-10-03; who counts as a viewer; views are not unique).
• Authenticity policy (X Help Center, read 2026-10-03; engagement spam rules and enforcement options).