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How TripCalc Calculates

Last updated: 2026-08-30 · Live since August 2026

1. The one-line version

Every number on TripCalc is an estimate for planning, not a quote. We compute outputs from documented formulas applied to curated public datasets, and this page documents where each dataset comes from, what it powers, and where it falls short.

2. The budget formula

Daily travel budgets are derived from a per-country cost model, not from user surveys or scraped booking data:

mid-range day = (mid-range hotel ÷ 2 travelers) + 3 meals + local transit & activities buffer

budget tier = mid-range day × 0.6

luxury tier = mid-range day × 2

The multipliers are deliberately simple and disclosed on purpose — we would rather you know the model is a model. National averages smooth over big city-vs-rural differences, so treat a country budget as a starting point, then adjust for your itinerary.

3. Currency rates

Internal calculations use a daily-refreshed mid-market snapshot. Rates are indicative planning figures: banks, cards and exchange bureaus add their own spread, so your real conversion will differ by a percent or three. On the converter pages themselves, the widget fetches live rates hour-to-hour — those are the rates to compare against your bank, not our snapshot.

4. Visa fees and vaccine prices

Visa fees, entry rules and vaccination prices are indicative figures from our curated dataset — useful for budgeting a trip, not a substitute for the official source. Immigration authorities change fees and requirements without notice; before you travel, confirm everything with the destination country's official immigration site or embassy.

5. The vaccine cost model

Vaccination cost calculators don't look up stored prices — they model a travel-clinic visit from the destination's cost-of-living index (US = 100), so a Japan estimate and an India estimate move with local prices. Each line item is a disclosed formula, rounded to whole dollars:

consult fee = round(35 + costIndex × 0.4)

hepatitis A (2-dose pair) = round(60 + costIndex × 1.1)

hepatitis B (3-dose series) = round(90 + costIndex × 1.5)

typhoid (1-dose) = round(35 + costIndex × 0.55)

yellow fever = round(150 + costIndex × 1.1) — risk countries only

tetanus booster = clamp(round(27 + costIndex × 0.28), 35, 55)

rabies pre-exposure (3-dose) = clamp(round(225 + costIndex × 1.75), 250, 400)

antimalarials = tripWeeks × ($12 doxycycline | $55 atovaquone-proguanil | $0)

Packages are then stacked from the line items: essential = consult + hepatitis A + typhoid; standard = essential + hepatitis B + tetanus booster; comprehensive = standard + yellow fever (where relevant) + rabies pre-exposure. Per-person totals add malaria tablets by trip week, and group totals scale linearly with travelers.

The result is an indicative planning band, not a quote — clinic pricing varies more than country pricing, and the same list abroad often costs a fraction of the home quote.

6. Health guidance — not medically reviewed

Health and vaccination guide content on TripCalc is compiled from two public references:

None of it is medically reviewed. We summarize published guidance so you can budget time and money; we do not give medical advice. For anything that affects your health — vaccines, prophylaxis, pre-existing conditions — consult a travel clinic or your doctor.

7. Datasets

What each dataset powers, when it was last audited, and where its limits are:

Country cost model

Powers: Travel budget calculators, daily-cost rankings, comparisons

Last audited: August 2026

Limitations: Derived model, not surveyed prices; city-level costs vary widely from the national average

FX rates

Powers: Currency converters, budget conversions, price comparisons

Last audited: Daily (automated refresh)

Limitations: Mid-market snapshot — cards, bureaus and banks apply their own spread on top

Tipping customs

Powers: Tipping calculators for 90+ countries

Last audited: August 2026

Limitations: Norms are cultural conventions, not rules; they drift and vary by venue type

Visa fees & rules

Powers: Visa cost calculators, visa requirement checks

Last audited: August 2026

Limitations: Indicative planning figures; fees and entry rules change frequently — always confirm with the destination's official immigration authority

Vaccine & health entry costs

Powers: Vaccination cost calculators

Last audited: August 2026

Limitations: Indicative clinic prices compiled from public sources; your actual cost depends on provider and insurance

Health guidance summaries

Powers: Health & vaccination guide content

Last audited: August 2026

Limitations: Compiled from WHO/CDC public guidance; NOT medically reviewed — consult a travel clinic for personal advice

City coordinates & geocoding

Powers: Distance calculators, flight-time estimates, jet lag tools

Last audited: August 2026

Limitations: Great-circle distances — actual travel distance is longer; flight times exclude layovers and taxi time

Airline baggage rules

Powers: Baggage allowance and carry-on calculators

Last audited: August 2026

Limitations: Rules are rewritten quarterly and differ by fare class — verify against your airline's contract of carriage

Live weather (Open-Meteo)

Powers: Weather lookups on destination pages

Last audited: Live (third-party feed)

Limitations: Forecasts are the provider's; accuracy decays beyond a few days

8. Update cadence

  • FX snapshot: refreshed daily (automated).
  • Monthly FX & dataset refresh: each month we re-validate the FX snapshot series and audit the datasets behind tipping, visa, health-cost and baggage figures.
  • Dataset audits: scheduled reviews of the cost model and guide content, with material fixes logged on our updates page.
  • Corrections: reported errors are fixed as found — see our editorial policy.

9. Known limitations

Our outputs are estimates for planning, not quotes. They cannot see seasonal price swings, city-vs-average gaps, your travel style, or today's actual fares. Before you book or commit money, verify the figure that matters against the official or live source — the booking site, your bank, the embassy, your airline. That verification step is yours; the starting estimate is ours.