Plus One Calculator — Extra Guest Estimates

About 60-75% of guests offered a plus-one will bring someone. Single guests are more likely to bring someone (70-80%) than those in established relationships who may already be invited as a couple. For casual parties the rate is lower (50-60%) as people feel less obligation.

Traditionally, plus-ones go to guests in established relationships, guests who will not know anyone else at the event, and single guests at formal events. For casual parties, it is common to extend a general plus-one to everyone. For weddings, be selective due to cost and venue capacity.

Each attending plus-one adds the full per-guest cost for food, drink, and favours. If your per-head cost is £30 and 15 plus-ones attend, that is £450 extra (before any cost buffer). This calculator budgets for the plus-ones that actually turn up — accepted plus-ones less expected no-shows — and applies an optional cost buffer (default 1.1) on top for unexpected extras. Always factor in estimated plus-ones when setting your initial budget.

Even after someone accepts a plus-one, expect roughly 5-10% of confirmed guests to drop out at the last minute through illness or clashing plans. This calculator deducts a default 10% no-show rate from accepted plus-ones so your head count and catering budget reflect who actually attends. You can adjust the rate (0-50%) under Advanced Options.

Yes, but be consistent with your criteria. Common rules: all guests in relationships get a plus-one, or only guests who know nobody else get one. Avoid offering to some single friends but not others in the same friend group.