How to capture the GCLID in OnceHub
Use Attributer to capture the GCLID with every OnceHub booking and send it through to your CRM, other tools, or back to Google Ads as an offline conversion.
Capturing the GCLID in OnceHub is straightforward with Attributer. Add a few hidden fields to your OnceHub booking form and Attributer will automatically pull the GCLID and pass it through with every new booking. And as a bonus, it captures UTM parameters and other attribution data at the same time.
Struggling to work out which of your Google Ads campaigns are actually generating bookings and customers? You're not alone.
Tools like Google Analytics can tell you how many people clicked your ads and visited your site, but they can't show you which of those visitors went on to book a call or become a paying customer. And without that visibility, it's really hard to know whether your ad spend is working or where to focus more budget.
The good news? There's a fix.
In this article, we'll show you how to use Attributer to capture the GCLID with every OnceHub booking, then send that data to your CRM and back to Google Ads as an offline conversion.
3 steps for capturing the GCLID in OnceHub
Getting the GCLID captured with every OnceHub booking is simple with Attributer. Here's how to set it up:
1. Install Attributer and add hidden fields to OnceHub
When you sign up for a 14-day free trial of Attributer, you'll get a small snippet of code to add to your website.
The exact process depends on what platform your site is built on (WordPress, Webflow, Squarespace, etc.), but you can typically drop it in through the settings section of your website builder.
Once the code is on your site, you'll need to add a hidden field to your OnceHub booking form. Just create a new hidden field and name it "GCLID". This gives Attributer somewhere to write the GCLID so it gets captured with every new booking.
2. Attributer stores the GCLID and passes it through with each booking
When someone clicks one of your Google Ads and lands on your site, Attributer pulls the GCLID from the URL and stores it in their browser. So even if they browse around for a while before booking, or leave and come back another day, the GCLID is still there waiting.
Then, when they complete a booking through OnceHub, Attributer writes the GCLID into the hidden field on your booking form.
3. GCLID is captured with each form submission
When someone completes a booking, OnceHub captures the GCLID right alongside all the other details they provided, like their name, email, and phone number.
You can view it in the bookings section of your OnceHub account, and it will show up in any booking notification emails you have set up.
From there, you can use OnceHub's built-in integrations or third-party tools like Zapier or Make to send the data through to your CRM or any other tools you use.
How to send the GCLID back to Google Ads and mark it as an offline conversion
Before the GCLID data can flow back to Google Ads, you need to create a conversion action to receive it.
Head into your Google Ads account and click Goals in the left sidebar, then select Conversions. From there, click the button to add a new conversion and choose Offline Conversion as the type.
Then, in the final screen when it asks you to add a data source, select the option to ‘Add data source later’.
Once your conversion action is set up in Google Ads, the next decision is figuring out which stage of your sales process should trigger the GCLID being sent back. This is worth thinking through carefully.
A lot of businesses default to sending the conversion when a deal is closed, which sounds logical but can actually work against you. Google's smart bidding strategies (like Maximise Conversions, Maximise Conversion Value, or Target CPA) generally need at least 50 conversions per month to function effectively.
If you're not closing 50 deals a month, you'll probably get better results by triggering the conversion at an earlier pipeline stage, like when a new deal is created in your CRM. You're still giving Google a meaningful signal since it's a lead your sales team has actually qualified, but you're also feeding smart bidding enough data to optimise properly.
Once you've decided on your trigger point, head into Zapier and create a new Zap. Set the trigger to match the moment you chose. For example, if you want the offline conversion to fire when a new deal is created in your CRM, use that as your trigger event.
Next, select Google Ads as the Action and then select the ‘Send Offline Conversion’ as the event.
Finally, you just need to map the GCLID from your CRM (or wherever you are storing it) to the correct field in Zapier.
That’s it! You have now set up offline conversions in Google Ads. It’s a good idea to test it’s working before piling money into ads, and you can read more about how to do that here.
Why Attributer is the best way to capture the GCLID in OnceHub
There are other ways to capture the GCLID with OnceHub bookings, so what makes Attributer worth using? Here are a few reasons it stands out:
1. Remembers the GCLID as visitors browse your site
Most other methods for capturing the GCLID only work if the visitor makes a booking on the exact page they originally landed on.
Works in theory, but presents a real problem in reality. If someone clicks your Google Ad and lands on your homepage, but then navigates to your Contact Us page to book a call, the GCLID is no longer in the URL and it never gets captured.
Attributer works differently. It stores the GCLID in the visitor's browser the moment they arrive on your site, so it doesn't matter which page they end up booking on, or even if they leave and come back days later. The GCLID gets captured every single time.
2. Captures UTM parameters as well
Attributer also captures attribution data for visitors who arrive through organic channels like Organic Search, Organic Social, Referral, or Direct traffic.
Sticking with the tax advisory firm example, if someone finds your site through a regular Google search rather than a paid ad, Attributer would capture something like this:
- Channel = Organic Search
- Channel Drilldown 1 = Google
- Channel Drilldown 2 = www.google.com (or whichever search engine domain they came from)
- Channel Drilldown 3 = tax advisory firms Sydney (or whatever keyword they searched, if available)
3. Captures information on users from organic channels
Attributer also captures attribution data for visitors who arrive through organic channels like Organic Search, Organic Social, Referral, or Direct Traffic.
Sticking with the executive recruitment firm example, if someone finds your site through a regular Google search rather than a paid ad, Attributer would pass through something like this:
- Channel = Organic Search
- Channel Drilldown 1 = Google
- Channel Drilldown 2 = www.google.com (or whichever search engine domain they came from)
- Channel Drilldown 3 = executive recruitment firms Sydney (or whatever keyword they searched, if available)
How Attributer helped Harris Federal Law track which Google Ads are truly generating customers & revenue
Harris Federal Law Firm is a Washington D.C. based legal practice that helps federal employees secure the benefits they're entitled to.
Like a lot of businesses running Google Ads, they had a visibility problem. Their campaigns were sending plenty of traffic to the site, and they could see that clearly enough in Google Analytics. But what they couldn't see was what happened after those visitors arrived. Which ones went on to book a consultation? Which ones became paying clients? And which campaigns were actually responsible?
They had no way to answer any of those questions, until they started using Attributer.
After getting everything set up, Attributer began capturing attribution data with every new booking, pulling through details like campaign, ad group, ad, keyword, and GCLID, and passing it all into their CRM alongside each new contact's details.
What that meant in practice was that for the first time, they could tie their Google Ads spend directly to real client outcomes, not just clicks and page views.
What they discovered surprised them. Several of their display campaigns looked great on paper, generating strong traffic numbers, but were barely converting any of those visitors into paying clients. Armed with that insight, they reallocated budget toward the search campaigns that were consistently bringing in new business.
The outcome was straightforward: more clients, and a lower cost to acquire each one.
"With Attributer we can see which campaigns are actually generating customers & revenue, rather than just website visitors. We were able to see that some of our campaigns were driving lots of visitors but few of them converted into leads and customers. Now we’re able to reinvest that budget into other campaigns that we can see are generating revenue."
Nick Child - Director of Marketing, Harris Federal Law Firm
Wrap Up
Want to know which Google Ads campaigns are actually generating bookings and customers?
Capturing the GCLID with every OnceHub booking and sending it back to Google Ads as an offline conversion is the best way to find out, and Attributer makes the whole process straightforward.
It stores the GCLID in the visitor's browser the moment they land on your site, so it doesn't matter if they browse around for a while or leave and come back later. Then, when they complete a booking, the data is written into hidden fields in your OnceHub booking widget and captured with each booking.
The best part? Getting set up takes less than 10 minutes and it's free to get started. Kick off your 14-day free trial today and start capturing the GCLID with every OnceHub booking.
Get Started For Free
Start your 14-day free trial of Attributer today!
About the Author
Aaron Beashel is the founder of Attributer and has over 15 years of experience in marketing & analytics. He is a recognized expert in the subject and has written articles for leading websites such as Hubspot, Zapier, Search Engine Journal, Buffer, Unbounce & more. Learn more about Aaron here.