400 km trip - how much fuel and will your tank last?

    Two consumption numbers, one tank gauge, four answers. Enter city and highway consumption, trip distance and current fuel level - get blended consumption, total liters needed, whether your tank will last, and a refueling plan with stop-by-stop distances and costs.

    A 400 km trip in a typical sedan with 8 L/100 km city and 5.5 L highway consumption (80% highway split) needs about 400 x 0.06 liters of fuel. But the real number depends on your city-to-highway ratio, tank size and current fuel level. Enter your car's numbers below to see whether your tank will last the full 400 km - or where you need to stop for fuel.

    Parameters

    Enter data for calculations

    From trip computer or vehicle specs

    At steady 90-120 km/h cruise speed

    How much of the trip is highway driving

    One-way distance in kilometers

    Full fuel tank capacity in liters

    Current fuel in tank before departure

    Current pump price per liter

    Form progress0 / 7 fields

    💡 Fill in all required fields to unlock the calculate button

    Two consumption numbers, one tank gauge, four answers

    Your car burns 8.5 L/100 km in the city and 5.8 L on the highway. A 350 km vacation trip is 80% highway. How much fuel do you actually need? Will a half tank get you there? This calculator blends city and highway consumption based on your trip profile, checks your current fuel level against the distance, and builds a refueling plan with stop-by-stop distances and costs.

    How to use this calculator - step by step

    1. City consumption - fuel usage in stop-and-go traffic from your trip computer. Typical: gasoline 7-10 L, diesel 5-8 L, SUV 9-14 L.
    2. Highway consumption - steady-speed usage at 90-120 km/h. Usually 30-40% lower than city.
    3. Highway percentage - what share of your trip is highway vs city driving. A typical vacation trip: 80-90% highway.
    4. Trip distance - one-way distance in kilometers.
    5. Tank capacity - your car's full tank size in liters.
    6. Current fuel level - how full your tank is right now.
    7. Fuel price - current pump price per liter for trip cost calculation.
    8. Read results - blended consumption, total liters needed, tank sufficiency and refueling plan.

    Key numbers at a glance

    30-40%
    less fuel on highway vs city
    5-10%
    reserve when gauge hits empty
    10-20%
    premium at highway rest stops
    15-25%
    extra consumption with full load

    Blended consumption reference table

    How city/highway split affects your real consumption (based on 8 L city / 5.5 L highway baseline):

    Highway % Blended L/100km Fuel for 300 km Cost at $1.60/L
    30% 7.25 21.8 L $34.80
    50% 6.75 20.3 L $32.40
    70% 6.25 18.8 L $30.00
    80% 6.00 18.0 L $28.80
    90% 5.75 17.3 L $27.60

    Common tank sizes by vehicle type

    Vehicle type Tank (L) City L/100km Highway L/100km Highway range
    City car (Fiat 500, VW Up) 35-40 6-7 4-5 700-900 km
    Compact (Golf, Civic, Corolla) 45-55 7-9 5-6 750-1,000 km
    Sedan/Estate (Camry, Passat) 55-70 8-10 5-7 800-1,200 km
    SUV (RAV4, Tucson, X3) 55-70 9-12 6-9 600-1,000 km
    Large SUV/Van (Tahoe, Transit) 70-100 12-18 8-12 600-900 km
    Diesel sedan (3 Series, A4) 55-66 5-7 4-5 1,100-1,500 km

    Practical examples

    Family vacation 350 km, compact car (50 L tank, half full): City 8 L, highway 5.5 L, 80% highway. Blended: 6.0 L/100km. Needs 21 L, has 25 L in tank. Result: no refueling stop needed, arrives with 4 L to spare.
    Weekend getaway 500 km, SUV (65 L tank, 3/4 full): City 11 L, highway 7.5 L, 90% highway. Blended: 7.85 L/100km. Needs 39.3 L, has 48.8 L. Result: no stop needed but arrives with only 9.5 L - refuel at destination.
    Business trip 700 km, diesel sedan (60 L tank, full): City 6 L, highway 4.5 L, 85% highway. Blended: 4.73 L/100km. Needs 33.1 L. Result: zero stops, arrives with 26.9 L remaining. Diesel range advantage.
    Cross-country 1,200 km, compact (50 L tank, full): City 8 L, highway 5.8 L, 80% highway. Blended: 6.24 L/100km. Needs 74.9 L. Result: 1 refueling stop after ~760 km, total fuel cost $119.80 at $1.60/L.
    City-heavy trip 200 km, SUV (65 L tank, quarter full): City 12 L, highway 8 L, 50/50 split. Blended: 10 L/100km. Needs 20 L, has 16.3 L. Result: need 3.7 L more - refuel before departure ($5.92).

    Did you know?

    A roof box adds 10-25% to highway consumption due to increased drag. Remove it when not in use.
    Tire pressure 0.5 bar below spec increases consumption by 2-3%. Check before every long trip.
    Running air conditioning at full blast costs 0.5-1.5 L/100 km extra. At highway speeds, AC is more efficient than open windows (drag penalty).
    Every 100 kg of extra weight adds roughly 0.3-0.5 L/100 km. Unload unnecessary items before a trip.

    Who uses this calculator?

    Vacation planner
    350 km to the coast, half tank, family SUV. Do I need to stop? How much will fuel cost? Can I avoid expensive highway stations?
    Daily commuter
    60 km round trip, 70/30 highway/city split. Will a quarter tank last the week? When should I refuel?
    Business traveler
    500 km to a client meeting, expense report needed. Exact fuel cost calculation with receipt-ready numbers.
    Road trip group
    1,200 km cross-country drive. How many stops? Where to refuel? Total fuel budget for the group.

    FAQ - Frequently asked questions

    Why does the calculator use a 95% fuel safety margin?
    Running a tank completely empty risks fuel pump damage (the pump uses fuel for cooling) and being stranded. The calculator assumes you refuel at 5% remaining - roughly when the fuel warning light comes on. This gives a safety buffer without wasting range.
    How accurate is the blended consumption estimate?
    The blend is a weighted average of city and highway consumption. It is accurate when your trip actually follows the selected split. In reality, transitions between city and highway driving (on-ramps, traffic jams near cities) create intermediate consumption. Expect 5-10% real-world variance. For best results, use trip computer averages from similar past drives.
    Should I fill up before or during the trip?
    Fill up before departure when possible. Highway rest stop stations typically charge 10-20% more per liter than regular stations. The exception: if your route passes through a region with cheaper fuel (different tax zones, border crossings), plan your stop accordingly. Apps like GasBuddy help find the cheapest stations along your route.
    How does a full car load affect fuel consumption?
    Each 100 kg of passengers and luggage adds about 0.3-0.5 L/100 km to consumption. A family of four with luggage (total extra ~300 kg) increases consumption by roughly 1-1.5 L/100 km. A loaded roof box adds another 1-2 L/100 km at highway speeds due to aerodynamic drag. Factor this in by adding 10-25% to your baseline consumption.
    Does the return trip use the same amount of fuel?
    Not always. Elevation changes matter: driving uphill on the way there means driving downhill on return (less fuel). Wind direction may reverse. Traffic patterns differ (Friday evening vs Sunday evening). Temperature changes affect consumption too. For a round trip estimate, multiply the one-way result by 2 and add a 5-10% buffer.
    What about electric vehicles?
    EVs can use this calculator by entering kWh/100 km instead of L/100 km and battery capacity instead of tank size. The math is identical. City consumption for EVs is often lower than highway (regenerative braking), so the blending works in reverse compared to gasoline cars. Adjust the highway percentage accordingly.

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    See also

    100 km Trip - How Much Fuel Do You Need?200 km Trip - How Much Fuel Do You Need?300 km Trip - How Much Fuel Do You Need?500 km Trip - How Much Fuel Do You Need?600 km Trip - How Much Fuel Do You Need?800 km Trip - How Much Fuel Do You Need?1000 km Trip - How Much Fuel Do You Need?1500 km Trip - How Much Fuel Do You Need?2000 km Trip - How Much Fuel Do You Need?

    Calculator verified by the LiczGrupa.pl team

    Content, formulas and results have been reviewed for accuracy and relevance by our team of specialists.

    Natalia Skrzek

    Reviewed by: Natalia Skrzek

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