Value-based bidding in Google Ads: what values to send and when to switch

Value-based bidding in Google Ads is Smart Bidding that optimizes for the value each conversion brings to the business, rather than the number of conversions. You run it with Maximize conversion value, optionally with a Target ROAS, and it only works as well as the values your conversion actions send. This guide covers what value-based bidding Google Ads campaigns need in practice: which values to send for ecommerce and for lead generation, how to price a lead without making the number up, what data to have before you leave Maximize conversions, where conversion value rules and customer lifecycle goals fit, and how to tell whether the switch worked.

What value-based bidding means: Maximize conversion value and Target ROAS

Volume-based strategies such as Maximize conversions and Target CPA treat every conversion of a given action as worth the same. A 300 baht order and a 30,000 baht order count as one conversion each, so the system bids to collect as many as the budget or the CPA target allows. Value-based strategies read the value attached to each conversion and bid more on auctions that look likely to produce high-value outcomes and less on the rest.

There are two settings to choose between:

• Maximize conversion value spends the daily budget trying to generate as much total conversion value as possible. It has no efficiency constraint, so it will spend the full budget even when the return on the last baht is poor.
• Target ROAS adds that constraint. You enter a target as a percentage, where 500% means 5 baht of conversion value for each 1 baht of ad spend. To work out your historical figure, take conversion value per cost and multiply by 100. Google is relabelling "Maximize conversion value with a Target ROAS" as simply "Target ROAS", and it says the behaviour does not change.

Google suggests a recommended target based on recent actual ROAS, which you can accept or replace. A target that is set too high limits the traffic your ads can win, which often reduces total conversion value rather than improving it. If conversion volume matters more to you than value, Google's own guidance is to stay on Maximize conversions or Target CPA.

What conversion values to send: ecommerce vs lead gen

Google Ads supports two ways of assigning value to a website conversion action. You can use the same value for every conversion, which Google calls static values, or use different values for each conversion, which are dynamic values passed at the moment the conversion fires. Codeless website setup only supports the same-value option. Dynamic values need the conversion event snippet or a tag manager setup that passes the value and currency at runtime.

Ecommerce: transaction value with a currency code

For an online shop, the natural value is the order value, sent dynamically with each purchase. Pass the currency as an ISO 4217 code string, such as 'THB'. If the tag omits a valid currency code, Google Ads ignores the tag's currency and uses the currency you set with the default value for that conversion action. Values are always reported in the account's billing currency, and when the currencies differ, Google converts them using the average daily exchange rate.

Decide whether the value is revenue or something closer to margin. Revenue is easy to pass from the checkout page, but if one product line carries far thinner margin than another, revenue-based bidding will chase the low-margin items just as hard. Some shops pass a margin-weighted value instead. Whatever you choose, choose it once and keep it consistent, because a change in what "value" means will look like a change in performance.

Lead generation: static values per action, or proxy values

A lead form has no price at the moment of submission, so lead-gen accounts usually assign values in one of three ways:

• Static values per action. A phone call, a quote request and a brochure download each get a different fixed value. Google's guidance counts this as reporting two or more unique values, because the values differ across goals.
• Proxy values. A lead score from your CRM or form logic, translated into a baht amount. Google says proxy values such as a lead score are acceptable.
• Downstream values. The actual sale value, imported back from your CRM through offline conversion import. This is the most accurate, but if the sale closes weeks after the click, the delay hurts bidding. Google's guidance is to consider an earlier goal, such as a qualified lead, when the final sale takes too long.

Assigning values to leads honestly

The honest way to price a lead is to work backwards from what leads of that type have actually been worth to you. Take a recent period of CRM data, count how many leads of each type became customers, and multiply that close rate by the average first sale or gross margin from those customers.

An illustrative example, using made-up numbers only to show the arithmetic: if quote requests closed at 10% and the average first job was 40,000 baht, a quote request is worth about 4,000 baht at the moment it arrives. If brochure downloads closed at 1% on the same job size, they are worth about 400 baht. Those two values tell the system that one quote request is worth about ten downloads, which is the ratio that matters for bidding.

Three rules keep this honest. First, use your own data, not an industry average you read somewhere. Second, revisit the values when close rates change, and annotate the date you changed them. Third, if you cannot measure close rates at all, use rough ratios between actions rather than precise-looking baht figures, and say internally that they are estimates.

Data requirements before switching from Maximize conversions

Google publishes minimums and recommendations. Check them against the current help pages before each switch, because they are updated:

• Volume: Target ROAS on Search and Shopping should have at least 15 conversions in the past 30 days at the conversion tracking level.
• Variety: you must report two or more unique values for the conversion goals the campaign uses. A single static value for one action gives the system nothing to rank.
• History: report values for at least three weeks or one to two conversion cycles, whichever is longer, before activating value-based bidding. Google advises against backfilling historical value data.
• Delay: report conversions as soon as they happen, or daily for offline feeds. Google recommends conversion delays under seven days. If no conversion data arrives within seven days of the click, ramp-up can take several months.

The cleanest sequence is gradual. Change the conversion goal first while still bidding to CPA, for example moving from all form submits to qualified leads. Start passing values while the campaign is still on Target CPA. Once values have been reporting for the required period, switch to value-based bidding and use the last 30 days of ROAS as the benchmark for the target.

How conversion value rules and customer lifecycle goals fit

Conversion value rules let you adjust the value you report, based on who converted, where or on what device, without changing your tags. You create them under Goals, then Conversions, then Value rules. Each rule has a primary condition (audience, device or location) and an optional secondary condition of a different type, and both must match for the rule to apply. All rules in an account have to use the same condition types, so plan them before you build the first one.

The actions are Add, which adds a fixed amount, and Multiply, which multiplies the passed value by a factor between 0.5 and 10. A Set action exists in beta. Only one rule applies to any conversion. The most specific location wins over a broader one, Customer Match audiences win over other audience types, and on a tie a Multiply rule beats an Add rule. Rules apply to Search, Shopping, Display, Hotel and Performance Max campaigns, and Smart Bidding uses the adjusted values in real time.

Customer lifecycle goals answer a different question: should a new customer be worth more than a returning one? The new customer acquisition goal has three modes. "Bid higher for new customers" (New Customer Value) works with value-based strategies, needs at least one Purchase conversion goal, and keeps existing customers in the auction at a lower priority. "High Value New Customer", in beta for Search, Performance Max and Shopping, bids higher again for new customers who resemble your most valuable ones and identifies them only from Customer Match lists you upload. "Bid only for new customers" (New Customer Only) excludes recognized existing customers and is meant for strict acquisition budgets or non-purchase goals such as lead generation. The setting is available in Performance Max, Search, Shopping and Demand Gen campaigns, and it relies on Customer Match lists, conversion tags or Google's auto-detection to tell new from existing customers.

Common mistakes with value-based bidding

• Equal values on every action. If a phone call and a newsletter signup both send 1, the strategy is volume bidding with extra steps. Values need to differ in proportion to real worth.
• Inflated values. Sending a lead value equal to the full lifetime value of a customer makes reported ROAS look excellent and makes the target meaningless. Bidding follows the number you send, so an inflated value encourages overspending on the action it inflates.
• Missing or wrong currency. A THB account receiving values without a currency code falls back to the conversion action's default currency. If someone set that default to USD, every value is converted at the exchange rate and inflated many times over.
• Zero or placeholder values. A dynamic tag that fires before the cart total loads can send 0 or a stray default such as 1.
• Double counting. Two primary purchase actions, for example a Google Ads tag and an imported GA4 purchase, both counted in the goal, roughly double the value the system sees.
• Moving the target too often. Google advises against several ROAS target changes within one conversion cycle. Each change resets what the system is aiming at before the last change has been measured.

How to measure the switch

The fairest test is a campaign experiment, where a control arm keeps the current CPA strategy and a trial arm runs value-based bidding on a share of traffic. Google's experiment guidance notes that ROAS target changes in the trial should be kept in line with any CPA changes in the control, or the comparison is unfair, and that a slow trial ramp can be helped by lowering the ROAS target.

When you read the results:

1. Judge value-based bidding on conversion value relative to cost. Google says not to judge it against the old Target CPA, because it is no longer trying to hit a CPA.
2. Exclude the most recent conversion-delay window from the comparison. Conversions that have not arrived yet make the newest days look worse than they are.
3. Wait one to two full conversion cycles before comparing actual ROAS with the target.
4. Check outside the ad platform. Compare the revenue or closed deals in your shop system or CRM for the same period, since Google Ads only knows the values you send it.
5. Watch conversion count alongside value. A rise in value with a sharp fall in volume can be correct, but it should be a decision you made, not a surprise.

What this means for Thai advertisers

Most Thai accounts bill in THB, so the simplest safe setup is to pass 'THB' in every tag and set THB as the default currency on every conversion action. Shops that also price in USD for foreign buyers can pass the order's real currency and let Google convert it, as long as the code is correct.

A larger gap is that many Thai sales do not finish on the website. Leads move to LINE chat or the phone, and many shoppers pay cash on delivery or buy on a marketplace instead. A form fill or a click on a LINE button is the last thing the tag sees, so the value sent at that moment is an estimate. Offline conversion import, keyed on the click ID or enhanced conversions for leads, is how a confirmed sale value gets back into Google Ads. For cash-on-delivery orders, decide whether the value is counted at order or at payment, and import adjustments for cancelled or returned orders if your system can produce them. Thai-language and English-language campaigns can also have quite different order values, which is a reason to keep them in separate campaigns so each one gets its own ROAS target.

Value-based bidding FAQ

Do I need Target ROAS to use value-based bidding?

No, Maximize conversion value is value-based bidding on its own, and Target ROAS is an optional efficiency constraint on top. Start without a target if you are not sure what ROAS your business can sustain, then add one once you have a few weeks of value data.

How many conversions does Target ROAS need?

Google lists at least 15 conversions in the past 30 days at the conversion tracking level for Search and Shopping campaigns. Other campaign types have their own minimums, so check the current Target ROAS help page for the type you run.

Can a lead generation account use value-based bidding?

Yes, as long as conversions carry at least two different values that reflect real differences in worth. Static values per action, proxy values from lead scoring, or imported sale values from a CRM all qualify.

Do conversion value rules change my reported conversion value?

Yes, the adjusted value appears in the conversion value column across account reporting, and Smart Bidding bids on it. Keep a record of the rules you set so that later readers of the reports know which values were adjusted.

Getting the values right first

Value-based bidding rewards accounts whose conversion values are accurate and honest, and it punishes the rest quietly. Relevant Audience's Google Ads management sets up conversion tracking with GA4, enhanced conversions and offline conversion imports so that Smart Bidding works from real revenue. If your shop runs product feeds, the Google Shopping service covers Merchant Center and Shopping campaigns, and if the tracking itself needs rebuilding, start with the GA4 setup and migration service.