Use Semrush when you want keyword and SEO competitors. Use Similarweb when you want traffic, audience, and market competitors. If your question is, “Find competitors for this brand,” the best answer is usually: use both, but start with the one that matches your goal.

Semrush vs Similarweb: the simple answer

Think of Semrush as a giant search detective.

It follows keywords. It checks rankings. It shows who steals clicks from you on Google.

Similarweb is more like a traffic spy.

It estimates visits. It shows channels. It tracks audience behavior. It tells you who gets attention from the same crowd.

So, if a brand sells running shoes, Semrush may show competitors ranking for “best marathon shoes” or “trail running sneakers.” Similarweb may show brands that shoppers visit before or after that running shoe site.

Both are useful. They just answer different questions.

When Semrush is the better pick

Choose Semrush when SEO is the main game.

It is great for finding:

• Organic search competitors
• Paid search competitors
• Keyword gaps
• Content rivals
• Domains ranking for the same terms

Let’s say your brand is a project management app. You enter your domain in Semrush. The tool may show that you share 3,800 keywords with Monday.com, 2,900 with Asana, and 1,700 with ClickUp.

That is clear. Those brands compete with you in search.

Semrush also gives you the Keyword Gap tool. This is where things get fun. And slightly painful. You can see all the keywords your rivals rank for, but you do not.

Honestly, it feels like opening your fridge and seeing someone else already ate your pizza.

For competitor research, this is gold. You are not guessing. You can see the missing topics. You can see search volume. You can see keyword difficulty. You can also spot weak rivals with good rankings.

That means you can build smarter content. Faster.

Where Semrush gets annoying

Semrush can feel busy.

There are a lot of menus. A lot of charts. A lot of shiny buttons asking for attention.

If you only want a quick list of business competitors, it may feel like too much. You may need to click through Organic Research, Traffic Analytics, Market Explorer, and Keyword Gap before the picture feels complete.

Expect to waste a few minutes cleaning the list too. Some sites may be blogs, directories, or review pages. They compete in search, but they may not sell the same thing.

That matters.

A blog ranking for “best CRM tools” is not the same as a CRM software company. Semrush may show both. Your job is to sort them.

When Similarweb is the better pick

Choose Similarweb when you care about market behavior.

It helps you find brands that compete for attention, not just keywords.

Similarweb is strong for:

• Total traffic estimates
• Direct traffic
• Referral traffic
• Social traffic
• Display traffic
• Audience overlap
• Similar sites

Imagine you are checking a fitness app brand. Semrush may show keyword rivals. Similarweb may show that users also visit calorie trackers, meal plan apps, smartwatch sites, and wellness stores.

That is a wider view.

It helps answer questions like:

• Where does this audience go next?
• Which brands get more direct traffic?
• Who wins on social?
• Who gets referrals from the same sites?
• Which channels are growing?

This is very helpful for brand strategy. It shows behavior beyond Google.

Where Similarweb gets annoying

Similarweb uses estimates.

That is normal. But it can still make your eye twitch.

Small websites may have limited data. Some traffic numbers may feel too neat. Some channel splits may not match your internal analytics.

So do not treat Similarweb numbers as perfect truth. Treat them as useful signals.

If Similarweb says Competitor A gets 1.2 million visits and Competitor B gets 430,000 visits, the exact numbers may be off. But the size gap is still useful.

That can guide your research.

Which tool finds brand competitors faster?

Similarweb is usually faster for a quick competitor list.

You enter a site. You check “similar sites” or competitors. You get a list. Done.

This is handy when a client says, “Who are our competitors?” and gives you one URL. Similarweb can give a first answer fast.

Semrush is better when you need proof.

It shows why each competitor matters in search. It can show shared keywords, ranking positions, traffic value, and paid ads.

So the split is simple:

• Need a quick market list? Use Similarweb.
• Need SEO competitors? Use Semrush.
• Need content ideas? Use Semrush.
• Need traffic channel insight? Use Similarweb.
• Need boardroom-style market sizing? Use Similarweb.

A simple use case

Say you manage marketing for a new pet food brand.

Your website gets 80,000 visits per month. You want to find competitors.

In Semrush, you find three domains that rank for the same keywords:

• Brand A shares 5,200 keywords with you
• Brand B shares 3,900 keywords
• Brand C shares 2,100 keywords

Great. These are your SEO rivals.

Then you check Similarweb. You see different data:

• Brand D gets 38% of traffic from social
• Brand E gets 44% from direct visits
• Brand F gets 27% from referrals

Now the story changes.

Brand A may be your search rival. Brand D may be your Instagram rival. Brand E may have stronger brand loyalty. Brand F may have better partnerships.

That is why using both tools works so well.

The best workflow to find competitors

Start simple. Do not overthink it.

1. Enter your brand domain in Similarweb.
2. Export the similar sites list.
3. Remove media sites, marketplaces, and random blogs.
4. Enter your domain in Semrush.
5. Check organic competitors.
6. Compare keyword overlap.
7. Mark each competitor by type.

Use labels like:

• SEO competitor
• Paid search competitor
• Social competitor
• Traffic competitor
• Product competitor

This stops the messy blob problem.

Because not all competitors are the same. Some steal your clicks. Some steal your customers. Some only steal your blog traffic and make your reports look sad.

So, which one should you choose?

If you can only pick one, choose based on your job.

Pick Semrush if you run SEO, content, PPC, or search strategy.

Pick Similarweb if you work on market research, media planning, partnerships, or brand strategy.

For most teams, the real winner is the combo.

Use Similarweb to spot the crowd. Use Semrush to inspect the fight. Similarweb tells you who gets traffic. Semrush tells you who wins keywords.

That gives you a cleaner competitor list. It also saves time. And it helps avoid silly mistakes, like calling a review blog your biggest business rival.

Final answer: Semrush is better for identifying search competitors. Similarweb is better for identifying brand and traffic competitors. Use both if your budget allows. Your competitor list will be sharper, cleaner, and much less weird.