Free tool
Use this budget reallocation calculator to estimate what could happen if you move budget from one channel to another — before committing the spend.
Move budget from
Move budget to
Δ revenue
+£7,200
Projected revenue
£50,000
from £42,800
Projected blended ROAS
2.78×
from 2.38×
Total revenue: before vs after the move
Move it — projected revenue rises
Pick your objective, then describe the channel you would move budget away from and the channel you would move it toward: their current spend and their current efficiency (ROAS). Enter how much you intend to move and — crucially — the marginal efficiency you expect the receiving channel to deliver on that extra budget. The calculator returns the change in total revenue, your new blended ROAS, and a clear recommendation.
The single most important input is the receiving channel’s marginal efficiency. It is almost never equal to that channel’s average, a distinction explained in marginal ROAS vs average ROAS. To pressure-test that figure for one channel, use the marginal ROAS calculator.
Moving budget has two sides. The donor channel loses the revenue that its budget was producing, and the receiving channel gains revenue at its marginal rate. In revenue mode the calculator removes move × donor ROAS and adds move × receiving marginal ROAS; in lead mode it removes move ÷ donor CPL and adds move ÷ receiving marginal CPL. The net of those two is your change in total revenue. Because total spend is unchanged, any improvement is pure efficiency — more output from the same budget.
The classic mistake is to drain the lowest-average-ROAS channel and pour it into the highest-average one. But the highest-average channel may already sit deep on its saturation curve, so its next pound returns far less than its average. Reallocating on marginal return — and respecting each channel’s headroom — is what turns a reshuffle into a genuine gain rather than a lateral move. It is the same discipline behind sound budget allocation, applied to budget that is already live.
A positive change with an improving blended ROAS is a green light: the receiving channel earns more on the moved budget than the donor was giving up. A result near zero means the two channels are balanced — there is little to gain, so leave the plan alone. A negative result means you would be moving budget into a weaker marginal return; hold, or test a smaller amount first. When several channels are in play, balance them together with the budget allocation simulator.
This tool depends on your estimate of marginal efficiency. ElenIQ’s Dex removes the guesswork by deriving each channel’s marginal return from your own historical data, then forecasting reallocations across the whole plan before spend is committed — the upgrade described in ad spend forecasting.
A budget reallocation calculator estimates what happens to your total revenue or leads, and to blended efficiency, when you move budget from one channel to another. It compares the outcome before and after the move so you can decide before committing the spend.
Move budget from a channel where the next pound returns little toward one where the next pound still returns a lot. The decision should be based on marginal return — the value of the next pound — not the highest average ROAS, because a channel can post a strong average while its marginal pound has stopped scaling.
Average ROAS reflects every pound spent so far, including the cheap, early ones. The channel with the best average may already be saturated, so adding budget there returns far less than the average suggests. Reallocation should follow the marginal ROAS of the receiving channel, which is why this calculator asks for it separately.
If projected revenue falls (or leads drop, or blended CPL rises) after the move, the receiving channel’s marginal return is weaker than what you are giving up. Hold the budget where it is, or test a smaller amount first to confirm the receiving channel can absorb it efficiently.
This calculator relies on your estimate of the receiving channel’s marginal efficiency. ElenIQ’s Dex derives each channel’s marginal return from your historical data, so reallocation decisions rest on a forecast curve rather than a manual guess — and it can rebalance a whole plan, not just two channels.
Use Dex to model full paid media scenarios with channel-level forecasting and budget movement, so spend always sits where the next pound works hardest.
Explore ad spend forecasting