Ad budget split calculator

Enter a total and a weight per channel; each channel gets its weight divided by the sum of weights, times the total. A 10,000 budget split 50/30/15/5 gives 5,000, 3,000, 1,500 and 500.

Weights rather than percentages is the deliberate choice here, because weights do not have to add to a hundred. That makes it easy to say "twice as much on search as social" without doing arithmetic first, and easy to add a channel without rebalancing everything else. The daily figure matters more than it looks: most platforms pace against a daily budget, and a monthly figure entered as a daily cap is the classic way to spend a month of budget in a weekend.