Budget a weekend getaway.
A short trip budget has one cost that is shared and several that are not, and separating them is what makes the per-person figure meaningful. Accommodation is a fixed total split across the group, so its share of the budget falls sharply as the group grows — which is why weekend trips get cheaper per head with four people than two. Travel, food and activities are all per person and scale linearly. Food is the item most often underestimated, because it accrues per person per day rather than as a single line. A 10 percent contingency is added automatically, since short trips have little slack and one unplanned dinner is a large share of a two-day budget.
Per-person variable cost
Per person = travel + food per day x days + activities
Trip total
Total = (accommodation + per-person cost x travellers) x 1.10 contingency
Because accommodation is the one shared cost. A 320 apartment split two ways is 160 each and split four ways is 80, while travel, food and activities stay the same per person. That single lever is why group weekend trips are consistently better value per head.
Short trips have no slack. On a two-week holiday one expensive meal averages out; over three days it is a meaningful share of the whole budget. Ten percent absorbs the unplanned taxi, the extra round and the entry fee you did not know about without derailing the plan.