Budget allocation is the way you divide your advertising money between campaigns, products, locations and channels. In Google Ads it mostly means deciding how much daily budget each campaign gets, and when to move money from one to another.
How budget allocation works
Google Ads does not take a single pot and share it out for you, unless several campaigns draw from one shared budget. Each campaign has its own average daily budget, and the account’s total spend is the sum of those choices. So allocation is a decision you make, campaign by campaign.
A sensible split starts with what each campaign is for. A typical lead generation account for a UK accountancy firm might have a brand campaign, a few service campaigns (tax returns, bookkeeping, payroll), a remarketing campaign and perhaps a Performance Max campaign. Each has a different job and a different cost per enquiry, so giving them equal budgets would be a coincidence, not a plan.
The useful question is not “which campaign has the best average return?” but “where would the next £100 do the most good?” That is the idea behind marginal ROAS. A campaign that returns £6 for every £1 on average may only return £2 on the extra pound, because it has already bought the cheapest, most relevant clicks. Meanwhile a campaign showing lost impression share due to budget with a healthy cost per conversion may be the better home for that £100.
Allocation also changes over time. Seasonal demand in the UK moves a lot: garden services in spring, heating repairs in autumn, gifts in November and December, accountants in the run-up to the 31 January Self Assessment deadline. A fixed monthly split ignores all of that.
Why it matters
Most accounts I look at are not short of money so much as spending it in the wrong places. Brand campaigns get more than they can use while a profitable service campaign is limited by budget every afternoon. Or a broad campaign with weak conversion rates absorbs half the spend because it was set up first and never revisited.
Good allocation lets a fixed budget produce more enquiries or sales without spending a penny more. It also makes reporting honest: when each campaign has a clear role and a budget that matches it, you can see which ones deserve more.
Common mistakes
- Splitting the budget evenly across campaigns regardless of their results.
- Judging campaigns on average return rather than on what extra spend would bring.
- Giving Smart Bidding campaigns so little budget that they never record enough conversions to learn from.
- Setting budgets once at launch and never revisiting them.
- Counting brand campaign results as proof that the whole account works.
How to act on it
List your campaigns with their spend, conversions, cost per conversion (or return) and lost impression share due to budget for the last 30 to 90 days. Mark which are limited by budget and which spend less than their budget allows. Move money gradually from campaigns where extra spend is unlikely to help to those that are capped and converting at an acceptable cost. Change budgets in steps of around 20% rather than doubling overnight, so automated bidding can adjust.
Review the split monthly and before each seasonal peak. Use my ROAS and break-even calculator to check whether each campaign clears your break-even point. If you would like this reviewed every month as part of running the account, it is a standard part of my PPC management service.