Google Ads vs Microsoft Ads: Server-Side Tracking & ROAS

Google Ads vs Microsoft Ads: which has better ROAS?

Google Ads vs Microsoft Ads ROAS comes down to three levers: what a click costs, how often it converts, and how much of the resulting revenue your tracking actually sees. In 2026 data, Microsoft clicks cost roughly a third less, but its desktop-heavy audience loses more conversions to browser-side blocking, so its ROAS is the one more likely to be understated.

That is the real answer to "which is better": neither wins on its own, and the platform dashboards cannot settle it. Google Ads brings scale and more mature measurement. Microsoft Ads (still called Bing Ads by many marketers) brings cheaper clicks and an audience Google cannot reach. Server-side tracking does not change the economics of either one. It changes how much of those economics you can see, and how much usable data each platform's bidding gets.

Here is the comparison at a glance:

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Why ROAS depends on tracking, not just the platform

ROAS is revenue divided by ad spend. Break it into its parts and the comparison becomes clearer:

ROAS = (conversion rate x average order value) / cost per click

Microsoft's advantage sits in the denominator (cheaper clicks). Google's usually shows up as scale and mature conversion signals rather than a better ratio. Tracking multiplies everything on top: if browser tags miss part of your conversions, the ROAS your dashboard reports is lower than the ROAS you actually earned, and Smart Bidding trains on that incomplete data.

A worked example (illustrative, not a forecast)

These numbers are assumptions chosen to show the mechanics. Replace them with your own.

The invisible shares come from a simple blend. Using the 37% US desktop and 15% US mobile ad-blocker rates from a 2020 survey, which are the latest device-level figures we found, a Google traffic mix of 45% desktop gives about 25% exposure, while a Microsoft mix of 80% desktop gives about 33%. Ad-blocker usage is only a proxy for script blocking, but it shows the direction.

Look at what happens to the gap. Microsoft's true ROAS is 35% higher than Google's. In the dashboards it looks only 21% higher, because Microsoft loses more to blocking. Tracking loss hides about 14 points of Microsoft's advantage. After server-side recovery, the gap is back to roughly 33%. A channel whose reported ROAS is understated is easier to under-invest in, so this matters for budget decisions, not just for reporting.

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Why Microsoft Ads traffic is exposed to more tracking loss

StatCounter's September 2026 data shows how lopsided Bing's audience is in the United States:

Bing's US desktop share is about 8.7 times its mobile share. Desktop is where ad blockers are most common, and desktop browsers such as Edge and Safari ship their own tracking prevention. So a Microsoft Ads click is more likely than a Google Ads click to come from a browser that blocks the UET tag.

There is an offsetting fact: Google carries far more spend, so even a smaller loss rate can be a larger absolute number of lost conversions. The rule of thumb is to prioritize by spend multiplied by exposure, not by either figure alone.

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Google Ads server-side tracking: Enhanced Conversions and click-ID uploads

Google gives you two server-side signals, and they work together:

• Click-ID uploads. Your server sends the gclid (or gbraid / wbraid for iOS app-to-web traffic) back with the conversion. Google keeps a GCLID for 90 days, and offline conversions uploaded more than 90 days after the click are not imported.
• Enhanced Conversions. First-party data such as an email address or phone number is hashed before it is sent, then matched to the Google accounts people were signed in to when they engaged with your ad, per Google's documentation. Enhanced conversions for web and leads were combined into a single setting from April 2026. Uploads that rely only on user-provided data have a shorter 63-day limit.

Two details matter if you build this yourself. First, Google has been moving offline-conversion and enhanced-conversions-for-leads uploads to the Data Manager API. According to Google's offline import guidance, those uploads were migrated to the Data Manager API and began to be blocked in the Google Ads API on June 15, 2026, with legacy access kept only for developer tokens that were already active. Custom scripts built on the old path need attention. Second, hashed user data should travel only when the shopper has granted ad_user_data consent. SignalBridge includes user data in a Google upload only when that consent is granted, and a click ID can still be uploaded on its own when consent blocks user data. For the full walkthrough, see our Google Enhanced Conversions setup guide.

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Microsoft Ads server-side tracking: msclkid and the Offline Conversions API

Microsoft's equivalent starts with the msclkid, the Microsoft Click ID. Creating a conversion goal automatically turns on auto-tagging, and the click ID is appended to your landing page URLs. Your server stores it and sends it back with the conversion through the Offline Conversions API.

Three things differ from Google:

• The Conversions API is still a pilot. Microsoft's CAPI documentation describes a server-side API that runs the UET event model, recommends using it alongside UET, and asks for hashed email and phone. But access is granted per account and cannot be self-activated, with no general availability date published. Most advertisers use the Offline Conversions API today.
• Consent is enforced. Since May 5, 2025, Microsoft has required consent signals for UET traffic from the EEA, UK, and Switzerland. Per Microsoft's FAQ, without Consent Mode or TCF it stops tracking UET-based conversions and populating remarketing lists.
• Matching is click-ID based. SignalBridge sends Microsoft conversions through the Offline Conversions API matched on msclkid. If a session has no click ID (auto-tagging off, parameters stripped by a redirect, or an expired click), nothing is uploaded to Microsoft for it. Google's path can still match on hashed user data alone when consent allows.

Our Microsoft Ads offline conversions guide covers the API details, and the Microsoft Ads conversion tracking pillar covers UET.

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Microsoft Ads attribution vs Google Ads attribution

The two dashboards do not count credit the same way, which makes a side-by-side ROAS comparison misleading unless you account for it.

Two consequences follow. First, a shopper who clicks a Google ad and later a Bing ad can be claimed by both platforms, so the sum of platform-reported revenue can exceed your real revenue. Second, a model difference alone can move reported ROAS without any change in real performance. The fix is to judge both on one neutral number: server-verified revenue from your own backend. Our guides on calculating true ROAS and why platform numbers never match go deeper.

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What the 2026 benchmarks say (and why they disagree)

Notice that the same report shows Microsoft with a lower CPA but a lower average ROAS. Both can be true, because the figures come from different advertiser mixes, order values, and conversion definitions. Other sources disagree too: WordStream's 2026 benchmarks, built from 13,000+ US search campaigns, put average CPC at $5.42, far above Silverback's $2.96 for Google Search.

The honest reading is directional. Microsoft is cheaper per click, the gap is narrowing as Microsoft's CPCs climb faster, and no benchmark can tell you your own ROAS. Break-even also matters more than any average: break-even ROAS is 1 divided by your gross margin, so a 30% margin needs about 3.3x before ad costs are covered.

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How to compare Google Ads and Microsoft Ads fairly

1. Use the same conversion definition on both platforms. Same event (purchase), same value rule (for example, post-discount and pre-tax), same currency. Exclude cancelled and refunded orders consistently.
2. Turn on server-side delivery for both. SignalBridge connects Google Ads in about 2 minutes and Microsoft Ads in about 3 minutes, with no code changes beyond one tracking script.
3. Keep the browser tags running. Google recommends the Google tag alongside Enhanced Conversions, and Microsoft recommends UET alongside server-side events. Follow each platform's deduplication rules (see our guide to event deduplication).
4. Sync ad spend and revenue in one place. Both integrations include automatic ad spend sync, so you can see server-verified revenue against spend for each platform as true CPA and ROAS.
5. Judge over at least 30 days against break-even. Compare platforms on true ROAS and on cost per new customer, not on platform-reported figures.
6. Reallocate gradually. If Microsoft's true ROAS is ahead, test more budget there. Microsoft's import tool copies campaigns and, with a UET tag associated, conversion goals from Google Ads, but review everything after import.

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What server-side tracking cannot fix on either platform

Be careful not to expect more than the technology delivers:

• Missing click IDs. If gclid or msclkid never reaches your site, or a redirect strips it, there is nothing to send back. Keep auto-tagging on and test your landing pages.
• Consent denials. Neither platform lets you work around them, and neither should you.
• Remarketing audiences. Server-side conversions restore measurement, but a blocked browser tag still cannot add that visitor to a pixel-built audience.
• Cross-platform double counting. Both platforms can claim the same order. Only a neutral revenue source resolves that.
• Expired windows. Google's 90-day click-ID limit and Microsoft's conversion window mean very slow sales cycles need earlier uploads.

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Which platform should you prioritize?

Silverback's report also describes Microsoft's audience as older and higher-income, which it says makes the channel especially valuable for financial services, B2B, healthcare, and legal advertisers. Treat that as one agency's view rather than a rule, and test it with your own data.

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FAQ

Is Microsoft Ads better than Google Ads for ROAS?

It depends on your account. Microsoft clicks typically cost about a third less on comparable keywords, which helps ROAS, but conversion rates, order values, and audience fit vary. Google offers more volume. Because the platforms attribute differently and lose different amounts of data to blocking, compare them on server-verified revenue against your break-even ROAS rather than on dashboards.

Does server-side tracking improve ROAS on Google Ads and Microsoft Ads?

It improves measured ROAS and the quality of data feeding Smart Bidding, but it does not change what you actually earned. Recovered conversions make dashboards more accurate, and better data can improve bidding over time. The underlying economics (click cost, conversion rate, order value) stay the same, so judge results on true ROAS.

Why does Microsoft Ads lose more conversions to ad blockers?

Its audience is desktop-weighted. StatCounter's September 2026 data shows Bing at 18.8% of US desktop search but only 2.15% of mobile, and desktop users block ads far more often than mobile users (37% versus roughly 15% in the US). More Microsoft clicks therefore come from browsers that can block the UET tag.

What is the difference between Google Enhanced Conversions and Microsoft Offline Conversions?

Enhanced Conversions sends hashed first-party data such as email, matched to signed-in Google accounts, and can supplement or replace click-ID matching. Microsoft's Offline Conversions API matches the conversion to the original ad click using the msclkid. Both recover conversions that browser tags miss, but Google also supports user-data-only matching when consent allows.

Does Microsoft Ads have a Conversions API?

Yes, but it is a per-account pilot. Microsoft publishes documentation for a server-side Conversions API that mirrors UET events, yet access must be requested through your Microsoft account team or support and cannot be switched on by you. Most advertisers use the Offline Conversions API, which is generally available.

Can I import Google Ads campaigns into Microsoft Ads?

Yes. Microsoft's import tool brings over campaigns, ads, targeting, and extensions, and can import conversion goals, but conversion goals that depend on UET need a UET tag installed and associated. Review every imported campaign afterward, since some settings are not carried over and bids may need adjusting.

How do I compare Google Ads and Microsoft Ads ROAS fairly?

Use one conversion definition on both platforms, send server-side conversions to each, and compare on server-verified revenue from your own backend rather than platform-reported figures. Judge over at least 30 days and measure against break-even ROAS, which is 1 divided by your gross margin. This removes the distortion from different attribution models and double counting.

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Related reading

• Google Enhanced Conversions: Complete Setup Guide (2026) — the full Google-side walkthrough
• Best Google Enhanced Conversions Tools in 2026 — compare ways to implement it
• Microsoft Ads Conversion Tracking: Complete Server-Side Setup (2026) — UET, offline conversions, and CAPI fundamentals
• Microsoft Ads Offline Conversions: Server-Side Setup Guide — msclkid capture and the Offline Conversions API
• How to Calculate True ROAS (When Pixels Miss Conversions) — the neutral number to compare platforms on
• Why Your Facebook and Google Ads Numbers Never Match (And What to Do About It) — why platform dashboards disagree
• Server-Side Tracking for Google Performance Max: Why Data Quality Matters — how conversion data quality drives Smart Bidding
• Ad Blocker Usage Statistics 2026: How Much Revenue Are You Missing? — desktop and mobile blocking rates
• How to Calculate Ad Spend Efficiency Beyond ROAS (CAC, LTV, MER) — judge channels on more than ROAS
• What is Event Deduplication? — run browser and server tracking together safely
• What is Server-Side Tracking? — the foundational guide