How does the calculator work?
It multiplies per-person costs by the number of travelers, works out how many hotel rooms you need from the sharing ratio, adds hotel tax, applies per diem meals with optional 75 percent days for departure and return, then adds group costs and a contingency. All math happens in your browser.
The formulas
| Line | Formula |
|---|---|
| Rooms | travelers ÷ people per room, rounded up |
| Lodging | rooms × nights × rate × (1 + tax %) |
| Meal days | travel days, with first and last at 0.75 if ticked |
| Meals | travelers × meal days × daily M&IE rate |
| Per-person lines | airfare, registration, ground transport, bag fees × travelers |
| Posters | number of posters × cost per poster |
| Total | subtotal + contingency % |
A worked example
Take four students sharing two rooms for a four-day, three-night meeting. With $420 airfare, a $209 room rate plus 13 percent tax, a $74 daily meal rate, $80 ground transport each, three posters at $55 and a 10 percent contingency:
- lodging: 2 rooms × 3 nights × $209 × 1.13 = $1,417
- meals: 4 travelers × 3.5 days × $74 = $1,036
- airfare $1,680, ground $320, posters $165
- subtotal $4,618, contingency $462, total about $5,080, or $1,270 per student
The rates in that example are illustrative. Look up the real per diem for your city on the GSA site.
Before you submit the budget
Check your institution's travel policy and the rules of the grant paying for the trip; some cap lodging at the federal rate, some require economy airfare booked through an agency, and some don't reimburse alcohol or certain incidentals. Our group travel guide covers policies and ways to cut costs.
Questions people ask
Where do the default numbers come from?
They are example values to show how the calculator works, not real rates for any city. Replace them with the GSA rates for your destination, your airfare quotes and the conference's fees.
How is the 75% meal rule applied?
With the box ticked, the first and last travel days count as three-quarters of a day for meals and incidentals, which is how federal travel rules and many university policies work. A one-day trip counts as 0.75 days.
Can I use this for a single traveler?
Yes. Set travelers to 1 and people per room to 1.