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Bus vs Train CO₂ Calculator — Per-Passenger Emissions (2025)

Enter From / To (or a manual distance), set occupancy, rail type and grid gCO₂/kWh, then instantly see which mode is lower on CO₂e per passenger. Auto-saves a shareable link.

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Inputs

If From/To are set, distance is auto-calculated.
🚌 Bus
🚆 Rail

Results

🚌 Bus

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Bus —
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🚆 Train

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Train —
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Per-Person CO₂e Comparison

Bars scale to the larger of the two totals. Units follow your selection (kg or lb). Round-trip & passenger count update live.

Enter a route or distance to compare.
Open all-in-one cost and emissions app
Passengers: 1 — totals are per-person. Group total appears here.
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    🧭 Overview

    The Bus vs Train CO₂ Calculator estimates the per-person carbon emissions for your trip based on distance, load factor, vehicle type, and—if the train uses electricity—the regional grid’s carbon intensity in gCO₂/kWh.

    By combining verified emission factors and real-world occupancy data, this tool helps you make environmentally smarter travel choices and understand how factors like seat utilization and national power mix affect overall climate impact.

    ⚙️ Methodology & Assumptions

    • Emission model: Per-person emissions = distance × emission factor ÷ load factor, with optional “upstream” (well-to-tank) uplift for energy supply chains.
    • Bus modes:
      • Coach (intercity) – efficient diesel power, ~25–35 gCO₂/p-km at 70–80% occupancy.
      • City bus – lower efficiency and load factor, typically 90–120 gCO₂/p-km (default baseline ≈104 g/p-km @ 60% LF before upstream).
    • Train modes:
      • Electric regional – 0.05–0.15 kWh/p-km depending on network.
      • High-speed rail (HSR) – 0.12–0.25 kWh/p-km derived from a 0.060 kWh/seat-km baseline (scaled by occupancy; ≈0.10 kWh/p-km at 60% LF) with higher average occupancy (~70%).
      • Diesel rail – ~70–110 gCO₂/p-km, similar to a full coach bus.
    • Grid intensity: Electric rail results depend on your region’s grid carbon factor (e.g., France ≈ 45 g/kWh, United Kingdom ≈ 220 g/kWh, Germany ≈ 380 g/kWh, USA ≈ 370 g/kWh).
    • Linear distance: The map uses great-circle (as-the-crow-flies) distance between cities for a simplified comparison; actual rail routes may be 10–25% longer.
    • Units: Calculations adapt automatically between km and miles, and you can switch between one-way and round-trip modes.

    📊 Formula

    Per-person CO₂ (g) = Distance × (EF_mode / LoadFactor) × (1 + UpstreamShare)

Where:
• EF_mode = base emission factor of the vehicle (gCO₂/km or gCO₂/kWh × energy use)
• LoadFactor = occupancy (0–1)
• UpstreamShare = optional energy supply chain uplift (e.g., +10%)

    For electric trains:
    EF_mode = EnergyUse (kWh/km) × GridIntensity (gCO₂/kWh)

    💡 Example Calculation

    Compare a 250 km one-way trip with defaults (passengers: 1, occupancy 60%, upstream +10%).

    • 🚌 Coach bus (baseline 27.7 g/p-km at 60% LF):
      Per-pax intensity with upstream = 27.7 × 1.10 = 30.47 g/p-km
      Total per person = 250 × 30.47 = 7,618 g ≈ 7.62 kg CO₂e.
    • 🚆 Intercity electric train (0.045 kWh/seat-km at 60% LF ⇒ 0.075 kWh/p-km):
      • EU avg grid 350 g/kWh: 0.075 × 350 = 26.25 g/p-km → with upstream ×1.10 = 28.9 g/p-km → 250 × 28.9 = 7,225 g ≈ 7.23 kg (train lower).
      • Germany 380 g/kWh: 0.075 × 380 = 28.5 g/p-km → with upstream 31.35 g/p-km → 250 × 31.35 = 7,838 g ≈ 7.84 kg (bus slightly lower).
      • France 60 g/kWh: 0.075 × 60 = 4.5 g/p-km → with upstream 4.95 g/p-km → 250 × 4.95 = 1,237 g ≈ 1.24 kg (train much lower).

    Takeaway: Results flip with the grid mix—on clean grids the train wins decisively; on fossil-heavy grids the bus can be similar or lower.

    🌍 Regional Grid Intensity & Emission Factors

    The calculator’s default grid factors are derived from the UK Department for Energy Security & Net Zero (2025 GHG Conversion Factors) and the IEA 2024 global electricity intensity dataset.

    RegionElectric Grid (gCO₂/kWh)Typical Rail Intensity (g/p-km)
    EU average350~26–30
    Germany380~28–32
    France60~4–6
    Poland720~54–60
    United Kingdom220~17–22
    USA (average)370~27–31

    Grid intensity varies daily with renewable generation. For precise results, enter your own custom gCO₂/kWh value from your country’s power operator or Ember Global Electricity Data.

    🚆 Train vs 🚌 Bus — Comparative Insights

    • Trains powered by renewable electricity can approach near-zero CO₂ per km.
    • Diesel trains or poorly loaded buses both exceed 80–120 g/p-km; occupancy is often the dominant factor.
    • On short routes (< 50 km), buses may outperform trains due to lower overhead energy for acceleration.
    • Over medium–long routes (100–800 km), electrified rail generally wins by 60–95%.

    📈 Typical Use Cases

    • Eco-travelers comparing intercity bus vs rail journeys in Europe or North America.
    • Corporate sustainability teams estimating employee travel emissions for ESG reporting.
    • Universities or students quantifying carbon savings from rail-first policies.
    • Planners benchmarking grid decarbonization impacts on transport CO₂ over time.

    ❓ Frequently Asked Questions

    Is train always greener than bus?
    Not necessarily. It depends on occupancy (load factor), distance, vehicle type, and—if electric rail is used—the grid carbon intensity. On clean grids and longer intercity routes, electric rail often wins; on short routes or low-occupancy trains, a coach bus can be competitive.
    Why does occupancy change my result?
    Per-person CO₂ divides total vehicle emissions by the number of riders. A bus or train at 25% full emits roughly four times more per person than one at 100%, all else equal.
    What about high-speed rail (HSR)?
    HSR typically uses more energy per km than regional or intercity services, but can still be low-carbon when powered by a clean grid and operated at good occupancy.
    Do longer trips favor rail?
    Often yes. Steady speeds and electrification tend to improve rail performance on medium-to-long intercity routes, while stop-and-go road services can be less efficient.
    Where do the CO₂ factors come from?
    We reference DEFRA/BEIS (UK Government) 2025 conversion factors, ICCT research, and global electricity-intensity data (e.g., OWID/IEA). This page harmonizes values with those sources and adapts them for occupancy and distance. See the Sources section for links.
    How accurate is the distance shown?
    The quick view uses great-circle distance (straight line) for fast comparison. Actual rail or road routes are usually 10–25% longer. Use the full planner for detailed multi-leg routing.
    What is grid carbon intensity, and why does it matter for trains?
    It’s the average grams of CO₂ per kWh of electricity. Electric-rail emissions scale with this factor. Cleaner grids reduce per-passenger results; fossil-heavy grids increase them. You can pick a preset or enter a custom value.
    Can I compare multiple regions or custom grid values?
    Yes. Choose a preset (EU, Germany, France, Poland, UK, USA) or enter a custom gCO₂/kWh to match a specific operator or time period.
    Does this include station energy, manufacturing, or maintenance?
    This quick view focuses on operational emissions. A full life-cycle assessment (LCA) typically adds about 10–20% for infrastructure and vehicle production (varies by system and study).
    Are electric buses included?
    Not directly. You can approximate one by using a comparable energy-per-km and grid-intensity setup in the full multi-mode calculator.
    What if my trip has multiple legs (e.g., city bus + train)?
    Open the full Travel Cost & CO₂ Calculator to chain multiple modes, regions, and legs.
    Can I export or share results?
    Yes — use the built-in Copy / Print / Export / Share actions to generate summaries for reports, coursework, or trip planning.
    What is the average carbon dioxide emissions factor in Germany?
    Germany has the sixth most carbon-intensive electricity in Europe at 381 gCO₂/kWh compared to just 56 gCO₂/kWh in France in 2023. Official Website of the International Trade Administration
    Why Electric Grid (gCO₂/kWh) for Germany is so high?
    Germany's electricity grid has a relatively high CO2 intensity (gCO₂/kWh) compared to many other European countries due to its reliance on fossil fuels like coal and gas for backup power, despite its investments in renewables. The country's coal phase-out plan is still in progress, and the intermittent nature of solar and wind power requires significant backup capacity, often supplied by fossil-fuel power plants, which raises the overall CO₂ emissions per kilowatt-hour. 

    📚 Data Sources

    • DEFRA/BEIS (UK Government): Official Greenhouse Gas Conversion Factors for Company Reporting 2025, providing verified CO₂ emission intensities for public transport modes (source).
    • ICCT (International Council on Clean Transportation): Research-based traction energy use factors for passenger rail and bus transport, harmonized with IEA/ETP datasets (source).
    • OWID (Our World in Data): Country-specific and regional electricity grid CO₂ intensities based on IEA 2024 energy data (source).

    Emission factors harmonized to the 2025 DEFRA/BEIS dataset with ICCT traction energy assumptions and OWID/IEA regional grid intensities. Real-world results vary with passenger load, vehicle technology, and local energy mix.

    Disclaimer:
    The Bus vs Train CO₂ Calculator provides indicative results based on public emission factors and average load assumptions. Actual performance varies by operator, vehicle age, route length, and energy mix. Values are for educational and informational purposes only and not for regulatory reporting. Always consult official transport or sustainability data for verified figures.