If you've been told a 4x ROAS is "good", that figure is doing less work than you think. ROAS - return on ad spend - measures how much revenue your Google Ads or Microsoft Ads campaigns generate relative to what you spend on them, and a 4:1 benchmark gets repeated across almost every generic PPC guide written for no audience in particular. The problem is that a 4x ROAS is comfortably profitable for a business running 60% margins and a straight loss for one running on 15%.

We see this gap constantly at Sway Digital. A client arrives convinced their account is underperforming because an agency quoted them a "5x or walk away" target, when their actual break-even point - the ROAS below which every sale loses money - sits closer to 2x. This guide covers the formula, the UK benchmarks that mean something once you know your industry, the break-even number that should replace any generic target, and how Google's Target ROAS bidding automates all of this once your account has the data to support it.

What Is ROAS?

ROAS stands for return on ad spend. It's the revenue your advertising generates for every pound spent, calculated as Revenue ÷ Ad Spend and expressed as a ratio or a percentage - a 300% ROAS and a 3:1 ROAS describe exactly the same result, £3 back for every £1 spent.

Most ad platforms calculate this automatically once conversion tracking is set up correctly, which is why Google Ads surfaces it directly as the "Conv. value / cost" column rather than leaving you to work it out by hand. The revenue figure should be genuinely attributable to the ad click - a sale, a booking, a lead value you've assigned deliberately - not total company revenue for the period, which would flatter the number without meaning anything.

At Sway Digital, ROAS is the headline metric we manage every Google Ads and Microsoft Ads account against, because it's the first thing that tells you whether spend is working before you get anywhere near profitability. It's a campaign health metric, not a profitability metric - it tells you whether ad spend is generating revenue efficiently, but says nothing about what happens to that revenue once your costs are subtracted. That distinction matters enough that it gets its own section below.

How to Calculate ROAS, With a Worked Example

The formula itself is simple - divide the revenue a campaign generated by what you spent on it:

ROAS = Revenue from ads ÷ Cost of ads

Say a trades business spends £800 on Google Ads over a month and generates £3,200 in booked jobs directly attributable to those ads. £3,200 ÷ £800 = 4, or a 4:1 ROAS - £4 back for every £1 spent. A service business running a lead-generation campaign would do the same calculation using the value it assigns to each lead, multiplied by the number of leads, rather than a direct sale price.

The harder part isn't the division, it's getting an accurate revenue figure into the equation in the first place. Enhanced conversions, offline conversion imports and genuinely accurate conversion values all feed into this number, and an account with broken tracking shows a ROAS that's wrong in either direction - understating real performance when conversions go unrecorded, or overstating it when the same sale gets counted twice across two different conversion actions.

Tip: Before trusting any ROAS figure, check the account's conversion actions are set to count genuinely valuable actions once each, not every form submission including a return visitor re-submitting the same enquiry a second time.

Use the calculator below to run your own numbers instantly - it applies the same formula above, plus the break-even check from later in this guide, automatically.

What Is a Good ROAS? UK Benchmarks by Industry

There's no single good ROAS - it depends entirely on your profit margin and industry. As a rough guide, UK ecommerce typically targets 3:1 to 6:1, SaaS and B2B software 3:1 to 5:1, legal services 5:1 to 8:1, and finance or insurance 5:1 to 9:1, but every one of these ranges means less than your own break-even number from the next section.

These ranges exist because margin and customer lifetime value vary so widely between sectors. A widely cited starting point is a 4:1 ROAS - £4 in revenue for every £1 spent - though the realistic range by sector looks closer to this:

• Ecommerce and retail: 3:1 to 6:1
• SaaS and B2B software: 3:1 to 5:1
• Legal services: 5:1 to 8:1
• Finance and insurance: 5:1 to 9:1
• Healthcare: 4:1 to 7:1

A business running Google Local Services Ads won't see a ROAS figure in the same way at all - that channel charges per lead rather than per click, so the number that actually matters is cost per booked job, not revenue divided by spend. Worth knowing before comparing it against a Search campaign's ROAS as though they're measuring the same thing.

A higher-margin business can genuinely afford to chase a lower ROAS and still turn a healthy profit, while a thin-margin business needs a much higher number just to stand still - which is exactly why these ranges work as a sense check and nothing more. The figure that tells you whether your specific account is profitable is the one below.

The Break-Even ROAS Number That Actually Matters

Break-even ROAS is the minimum ROAS at which a campaign stops losing money, calculated as 1 ÷ profit margin. A business with a 25% profit margin needs a 4:1 ROAS just to break even - anything below that loses money regardless of how healthy the overall number looks against someone else's benchmark.

Take a product that sells for £50 with £32 in combined production, fulfilment and payment processing costs. That leaves £18 in gross profit, or a 36% margin (£18 ÷ £50). Applying the formula: 1 ÷ 0.36 = 2.8 - this business needs at least a 2.8:1 ROAS before a single advertising pound turns a profit. A "disappointing" 3:1 ROAS against someone else's quoted 5x benchmark is actually a genuinely healthy result at this margin.

This is why a generic industry benchmark can mislead a business owner into pulling budget from an account that's working, or leaving one running that's quietly losing money on every sale. Calculating your own break-even ROAS before judging any campaign number is worth doing once and keeping on hand - the calculator earlier in this guide does it instantly - and it changes every subsequent conversation about whether a campaign is "performing".

Tip: Recalculate your break-even ROAS whenever your costs change. A supplier price increase or a new payment processor fee shifts the number even when nothing about your ads has changed at all.

ROAS vs ROI: Why a 400% ROAS Can Still Lose Money

ROAS measures revenue against ad spend alone. ROI measures profit against every cost involved in running the business, including staff, software and overheads. A campaign can show an impressive ROAS while the business behind it loses money once those wider costs are counted properly.

A useful illustration: a business generates £100,000 in revenue from £25,000 of ad spend, giving a 400% ROAS - a figure that looks strong against any benchmark in this guide. But once £80,000 in other costs (staff, stock, software, fulfilment) are factored in, the business actually made a loss, putting ROI at roughly -5%. The ads did their job. The business, as a whole, didn't.

Neither metric replaces the other. ROAS is the right number for optimising a campaign day-to-day because it's immediate and platform-reported, while ROI is the number that tells you whether the business built around that campaign is genuinely sustainable. Track both, and treat a strong ROAS as necessary but never sufficient on its own.

Target ROAS Bidding in Google Ads: How It Works

Once an account has enough conversion data, Target ROAS bidding lets Google's Smart Bidding system set bids automatically to hit a ROAS target you choose, rather than you adjusting bids manually campaign by campaign. Set a target of 500%, for example, and Google aims to generate £5 in conversion value for every £1 spent, bidding more aggressively on searches it predicts will convert at high value and pulling back on ones it predicts won't.

Google requires a minimum of 15 conversions in the past 30 days for Search and Shopping campaigns before Target ROAS becomes available, plus at least four weeks or one to two full conversion cycles of historical data to calibrate against. An account without that volume isn't ready for it yet, whatever a generic bidding guide elsewhere suggests - manual bidding or Maximise Conversion Value is the more honest choice until the data actually exists to support an automated target.

From June 2026, Google renamed "Maximise conversion value with a Target ROAS" to simply "Target ROAS" inside the interface - the underlying bidding behaviour hasn't changed, just the label, so don't expect different results from an account that already uses it under its old name. The same Smart Bidding logic underpins Performance Max campaigns, which can run on a Target ROAS goal across Search, Display, YouTube and Shopping inventory at once, and increasingly sits behind AI-assisted campaign setup tools that now automate the targeting layer as well as the bidding itself.

Tip: Set your Target ROAS at or slightly above your break-even number from earlier in this guide, never at an arbitrary industry average. Google will optimise hard towards whatever target you give it, including one that's quietly unprofitable.

How to Improve a Weak ROAS

A ROAS below your break-even number usually traces back to one of a small number of causes, and most of them are fixable without increasing budget at all.

• Broken or incomplete conversion tracking - the single most common cause. If Google Ads can't see which clicks convert, Smart Bidding is optimising blind, and your reported ROAS is simply wrong.
• No negative keyword list - budget leaking to irrelevant searches that will never convert drags the average down across the whole campaign, not just the wasted clicks themselves.
• Generic audience signals on Performance Max - PMax needs your actual customer data, such as website visitors and customer match lists, to find similar high-value searches, not Google's default targeting.
• Landing pages that don't match search intent - sending a high-intent click to a generic homepage instead of a page built around that exact search wastes spend that tracking will faithfully record as a non-conversion.

We saw this directly with Rainbow Garden Buildings, an ecommerce client whose Google Ads account had exactly these problems - a messy account structure, no Smart Shopping or Performance Max in use, and conversion tracking that wasn't capturing the full picture. Restructuring the account, adding Performance Max and fixing tracking took £1,988 in ad spend to £57,400 in revenue - a 2,899% ROAS, at a £0.15 average cost per click. None of that came from a bigger budget. All of it came from fixing what was already broken.

Organic search activity also lifts blended account performance over time - a visitor who finds you organically and later converts through a branded paid search ad still shows up inside that campaign's ROAS, even though organic did part of the work to get them there. Accounts that invest in both channels together tend to see paid ROAS climb as brand recognition grows, not because the ads themselves improved, but because fewer clicks are needed to close an already-warm visitor.

Conclusion

Three things worth taking from this: know your break-even ROAS before judging any campaign number, treat industry benchmarks as a sense check rather than a target, and hold off on Target ROAS bidding until your account has the 15 conversions in 30 days Google needs to calibrate against properly.

If you want an honest read on whether your account's ROAS is genuinely good for your margins - not just against a generic benchmark pulled from a blog post - book a free 30-minute strategy call and we'll go through your actual numbers together. And if a growing share of your potential customers are now asking ChatGPT or Google's AI Overviews what counts as a good ROAS before they ever see your ad, it's worth checking whether your own site shows up in those answers at all - get the free AEO report to find out.

FAQ

What counts as a good ROAS for a small business in the UK?

It depends on your profit margin more than your industry. As a rough guide, UK ecommerce typically sits between 3:1 and 6:1, while legal and finance services run higher at 5:1 to 9:1 given their larger margin per sale. Calculate your own break-even ROAS (1 ÷ profit margin) before comparing your account against any of these ranges.

What's the difference between ROAS and ROI?

ROAS measures revenue against ad spend alone, while ROI measures profit against every cost involved in the business - staff, software, stock and overheads included. A campaign can report a strong ROAS and still contribute to an overall loss once those wider costs are factored in, so the two metrics answer different questions and neither replaces the other.

How do I calculate my break-even ROAS?

Divide 1 by your profit margin expressed as a decimal. A business with a 30% margin needs 1 ÷ 0.30 = 3.33, meaning a 3.33:1 ROAS just covers its costs - anything above that is genuine profit.

Can a high ROAS campaign still be unprofitable?

Yes, if the margin on what's being sold is thin enough. A 4:1 ROAS looks strong on a product with a 40% margin, but the same 4:1 result is a loss-making campaign for a product with only a 15% margin, because the break-even ROAS at that margin is closer to 6.7:1.

Is Target ROAS bidding worth using with a small budget?

Only once your account has at least 15 conversions in the past 30 days for Search or Shopping campaigns, which is Google's minimum for the algorithm to calibrate against. Below that threshold, manual bidding or Maximise Conversion Value gives Google less room to optimise towards an unproven target, and is the more reliable choice until the data builds up.