Methodology

Last updated: 20 June 2026
App version covered: 1.0 · Factor vintages included: 2024, 2025, 2026

This document explains how ScopeSimple calculates carbon footprints and greenhouse gas (GHG) inventories: where our emission factors come from, what we include and exclude, and every simplification we make. We publish it because a number is only as trustworthy as the method behind it. Our guiding principle: every simplification should be documented transparently enough that a professional could verify our approach.

ScopeSimple is built for individuals and small-to-medium businesses, not industrial operators or regulated facility-level reporting. The figures it produces are estimates for self-assessment and education — not a certified or assured emissions statement. (See our Terms of Service for the full disclaimer.)

1. The greenhouse gas framework

1.1 What we measure

ScopeSimple expresses results in tonnes of carbon dioxide equivalent (tCO₂e) — the standard unit that converts every greenhouse gas into the amount of CO₂ that would cause the same warming, using each gas's Global Warming Potential (GWP).

1.2 Scopes 1, 2, and 3

The GHG Protocol — the most widely used emissions accounting standard — divides emissions into three "scopes":

• Scope 1 — Direct emissions from sources you own or control: burning natural gas or heating oil on-site, fuel burned in vehicles you operate, and refrigerant gases that leak from your equipment.
• Scope 2 — Indirect emissions from purchased energy: the emissions produced elsewhere to generate the electricity (and purchased heat or steam) you use.
• Scope 3 — All other indirect emissions across your value chain: purchased goods and services, business travel, employee commuting, waste, and more.

ScopeSimple covers Scope 1 and Scope 2. It does not calculate Scope 3.

1.3 Why we stop at Scope 2 (and why that matters)

Scope 3 is often the largest part of an organisation's true footprint — commonly two to four times the size of Scope 1 + 2 for many small businesses — but it is also by far the hardest to estimate, requiring supply-chain data most small organisations don't have. We deliberately focus on the Scope 1 + 2 figures we can calculate rigorously rather than produce a low-confidence Scope 3 guess.

We state this limit plainly in the app and in every exported report, so a Scope 1 + 2 figure is never mistaken for a complete footprint. Scope 3 estimation is on our future roadmap.

2. Emission factors: sources

An emission factor converts an activity (kilowatt-hours of electricity, litres of fuel) into emissions. ScopeSimple uses official, published factors from the recognised national authority in each of our four launch markets:

Every factor in the app carries its specific source, publication, and vintage year in our internal factor database, and is listed in the tables in Section 6 below. The exact editions in use are:

• Canada: ECCC Emission Factors and Reference Values v3.0.
• United States: EPA eGRID (eGRID2022 and eGRID2023 rev.2) and the EPA GHG Emission Factors Hub 2025.
• United Kingdom: UK Government / DEFRA Greenhouse Gas Conversion Factors (2024, 2025, and 2026 editions).
• Australia: DCCEEW National Greenhouse Accounts Factors (2024 and 2025 editions).

Factor sets are refreshed as each national authority publishes. The UK's DEFRA 2026 conversion factors have been released and are applied for the 2026 vintage. Where an authority has not yet published its latest annual edition — for example Australia's NGA 2026, expected later in 2026 — the most recent published edition (2025) is carried forward for that vintage and refreshed in routine annual maintenance, as noted per row in Section 6.

3. How calculations work

3.1 The basic method

For each input, ScopeSimple multiplies your activity by the matching emission factor for your region and the relevant year, then sums the results:

emissions (kg CO₂e) = activity quantity × emission factor (kg CO₂e per unit)

Results are summed across all inputs and converted to tonnes (÷ 1000).

3.2 Scope 1 — direct emissions

• Stationary combustion — natural gas, heating oil, propane burned on-site, converted using the fuel's combustion factor.
• Mobile combustion (fleet) — fuel burned in vehicles you operate, by fuel type (gasoline, diesel, etc.).
• Fugitive emissions — refrigerant gases that leak from air-conditioning and refrigeration equipment, converted by the refrigerant's GWP (see Section 5.4).

3.3 Scope 2 — purchased energy

• Purchased electricity — kWh × your region's grid emission factor. This is the single most region-sensitive number in the app, which is why we apply a province/state-specific factor rather than a national average (Section 4).
• Purchased heat / steam — where applicable.

3.4 Personal mode

Personal mode uses the same engine, focused on the two largest household sources: home energy (electricity + heating fuel) and transport (personal vehicles). Home energy is divided by the number of people in the household — because a home is heated and powered once regardless of how many people live there — while transport stays personal, so the result is a true per-person footprint. That number is then compared, for context, against a national-average per-person figure.

Importantly, that comparison baseline is household-direct emissions per person — the emissions from people's own homes and personal travel — not a whole-economy per-capita figure (which would fold in industry, agriculture, and energy production that an individual doesn't control). This makes the comparison like-for-like with what the app actually measures.

Each figure is built on a uniform method — residential energy (including home electricity) plus personal road transport, divided by population — using each country's official national statistics. Canada's is a directly published household figure; the United States and United Kingdom are derived from primary government sources; Australia's is a derived estimate carrying the lowest confidence of the four (one input is drawn from a building-sector analysis rather than a primary government statistic) and is flagged for periodic review. These averages are used only as a contextual comparison and do not affect your computed footprint.

3.5 Reporting periods (snapshot vs. tagged)

• Free tier uses a snapshot model: you enter figures for a typical month or year, and the app reports that snapshot without attaching it to a specific calendar period.
• Premium / Business can tag a specific reporting period (a month, a quarter, or a fiscal year). Tagging is what enables period-correct factor selection (Section 5.2) and audit-grade history.

4. Regional variation (why your province/state matters)

Electricity grid emissions vary enormously by region, because the mix of generation (hydro, nuclear, gas, coal, wind) differs. A kilowatt-hour in a hydro-dominated grid can carry a small fraction of the emissions of the same kilowatt-hour in a coal-dependent grid. Using a national average would therefore be misleading for most users.

ScopeSimple applies the emission factor for your specific province, territory, or state wherever the source data supports it, and uses a national figure only where a regional one is unavailable.

4.1 Delivered-basis electricity

Our electricity factors are applied on a delivered (consumption) basis — reflecting the emissions associated with the electricity actually delivered to and consumed in your region. This is the basis most appropriate for an end-user's Scope 2 reporting across all four countries.

All electricity factors are applied on a delivered basis (reflecting electricity consumed in the region). For the United States, the published eGRID output rates are grossed up for transmission and distribution losses so the factor reflects delivered rather than generated electricity. The per-row notes in our factor database record any country-specific nuance.

5. Vintages, periods, and other documented choices

5.1 Factor vintages

Emission factors are republished periodically (typically annually) as grids decarbonise and methods improve. ScopeSimple ships multiple vintages — currently 2024, 2025, and 2026 — rather than only the latest, so that a calculation for a past period can use the factors that were actually in force then.

5.2 Period-correct factor selection

When a Premium/Business user tags an entry to a specific reporting period, ScopeSimple looks up the factor vintage in force during that period rather than today's. For example, an inventory tagged to a 2024 period uses 2024 factors. For untagged snapshot entries, the current vintage is used.

5.3 The fiscal-year vintage rule (important)

A fiscal year usually straddles two calendar years, which means it could touch two factor vintages. ScopeSimple does not blend factors across the calendar boundary — each entry uses exactly one vintage. For a fiscal year, we apply the vintage of its start year, on the basis that the start year covers the majority of the reporting months.

Worked example: a fiscal year ending 31 March 2026 runs April 2025 → March 2026 — nine of its twelve months fall in 2025, so it is calculated with 2025 factors. This means a report labelled "FY2026" is computed using 2025 factors. This is a deliberate, defensible simplification (majority of months), but we state it openly so the choice is never hidden.

Edge case we acknowledge: for a fiscal year ending in June, the split is 6 months / 6 months, so "majority" is arbitrary; we still apply the start-year vintage for consistency. Blended-vintage calculation and month-by-month assembly of fiscal years are planned future enhancements.

5.4 Refrigerant GWP table

Fugitive refrigerant emissions are converted using a single, fixed Global Warming Potential table based on the IPCC Fourth Assessment Report (AR4), 100-year basis, applied consistently across the whole app. AR4 is the basis used across all four launch markets (it underpins US EPA reporting under 40 CFR Part 98, Australia's accounts, and the GHG Protocol's AR4 values), which makes it the right common standard for ScopeSimple. A Global Warming Potential is a global physical constant for a given IPCC report, so — unlike electricity — a single value per refrigerant is correct in every region. The AR6 values are shown alongside for reference only; the app does not use them.

Source: GHG Protocol Global Warming Potential Values (IPCC AR4 100-year basis), consistent with US EPA and Australian DCCEEW reporting requirements.

5.5 Fuel-use factor sub-types

ScopeSimple models the household and small-business fuels that are actually metered or purchased: natural gas, heating oil, propane (LPG), gasoline/petrol, and diesel. Each is converted with the country-specific combustion factor in Section 6.5, which already combines CO₂, methane, and nitrous oxide into a single CO₂e value per unit. The app does not break these into finer sub-types (for example by grade or blend); it applies one representative factor per fuel per country. This is a deliberate simplification appropriate to self-assessment, and we state it plainly rather than implying a precision the inputs don't support.

5.6 Personal-mode methodology

Personal mode produces a genuine per-person footprint. Home energy — electricity, natural gas, heating oil, and propane, with any solar generation applied as a reduction to electricity — is divided by the number of people in the household, because a home is heated and powered once regardless of how many people live there. Personal transport (up to three vehicles by fuel type, plus an optional public-transit estimate) is not divided, because it's individual. The two are then combined into your personal total.

This design — sharing the household inputs across occupants while keeping personal inputs individual — is what lets your result be compared like-for-like against the per-person national averages in Section 3.4. (Earlier versions computed a whole-household total, which made larger households look worse than they were against a per-person benchmark; that mismatch is resolved in the current version.) The public-transit estimate uses a single indicative per-minute factor rather than a region-specific one, which we note as a simplification.

6. Full emission-factor tables

The complete factors used by ScopeSimple are listed below by country and vintage. Each row shows the region, the factor, its unit, and its source.

6.1 Canada — electricity grid factors (kg CO₂e/kWh)

6.2 United States — electricity grid factors (kg CO₂e/kWh)

ScopeSimple uses official EPA eGRID delivered-basis factors for all 50 states plus the District of Columbia. A representative range is shown below — from the highest-carbon grids (e.g. West Virginia, Kentucky) to the lowest (e.g. Vermont, Washington) — to illustrate the spread. The complete state-by-state set is applied in the app and available on request.

6.3 United Kingdom — electricity grid factor (kg CO₂e/kWh)

6.4 Australia — electricity grid factors (kg CO₂e/kWh)

6.5 Combustion factors (Scope 1 fuels)

Combustion factors are country-specific (kg CO₂e per unit), combining CO₂, CH₄ and N₂O. Sources: Canada — ECCC NIR v3.0; USA — EPA GHG Emission Factors Hub; UK — DEFRA GHG Conversion Factors; Australia — DCCEEW National Greenhouse Accounts Factors. See each national source for the precise vintage applied.

7. Trip & travel calculator

ScopeSimple includes a trip calculator for estimating the footprint of a vacation or journey — flights, accommodation, ground transport, rail, ferry, and cruise. Because a flights calculator in particular invites scrutiny, this section documents every factor and every choice behind it. All figures are per person, and unless noted every factor is DEFRA 2026 on a full-lifecycle basis — direct combustion plus well-to-tank (WTT, the upstream emissions of producing and delivering the fuel) — expressed in kg CO₂e per passenger-kilometre.

7.1 Flights

Flights are the most carefully-treated part of the calculator. The factors are built on the most complete basis DEFRA publishes: direct combustion + radiative forcing (RF) + WTT. Radiative forcing (an approximately 1.9× uplift) accounts for the extra warming effect of aircraft emissions released at high altitude — contrails, nitrogen oxides, and water vapour that do more warming up there than the CO₂ alone. We include RF deliberately: it is the most honest, most complete position, even though it makes the flight number larger. We would rather show the fuller impact than a flattering under-count.

Cabin class matters. A first-class seat carries roughly two to four times the footprint of economy on the same flight, because premium cabins take up far more space and weight per passenger — fewer people occupy the same aircraft.

Two deliberate choices we flag openly:

• Band mapping. For overseas trips the app uses DEFRA's "International, to/from non-UK" band — a set purpose-built for flights that don't touch the UK, with the cabin-class split shown above. For flights within a country, it uses DEFRA's "Domestic" factor (0.26278) as a proxy. ⚠️ Honest caveat: DEFRA "Domestic" is specifically UK-domestic, so using it for, say, a Toronto–Vancouver flight is the least geographically precise element of the calculator. It is a defensible proxy for short internal hops, but we name it as the weakest match rather than hide it.
• Short-haul emits more per km than long-haul. This looks backwards but is correct: take-off and climb burn a disproportionate amount of fuel, and on a short flight that burn is spread over fewer kilometres. The calculator reflects this rather than "correcting" it.

If you enter flight time instead of distance, the app converts using an effective speed of 800 km/h (distance = hours × 800). That is deliberately below the ~880–920 km/h raw cruise speed, because gate-to-gate block time includes taxi, climb, descent, and holding — so the real door-to-door distance per quoted hour is lower. Entering distance directly is preferred when you know it; the hours path is a conservative fallback.

7.2 Accommodation

DEFRA 2026 publishes a per-country "Hotel stay" factor in kg CO₂e per room, per night (drawn from the Cornell Hotel Sustainability Benchmarking index), covering around 55 countries. The app stores the raw per-room value and divides by room occupancy (default: 1 person per room) to get your per-person share.

Around 30 destinations are stored in total. ⚠️ Important honesty note: DEFRA lists 0 for some countries where its source simply has no data (for example Greece, Ireland, and New Zealand) — this is a data gap, not zero emissions. The app never presents 0 as if a hotel were carbon-free; it substitutes a sensible global default (~20 kg per room-night) for any country with missing data.

7.3 Ground transport (car)

Car travel reuses the same DEFRA 2026 road factors described elsewhere in this methodology, applied per vehicle-kilometre and divided by the number of occupants for the per-person share.

⚠️ The EV figure uses UK grid intensity, so it is a caveat for non-UK users whose local grid may be cleaner or dirtier. Both are per-vehicle and divided by occupancy.

7.4 Rail

7.5 Ferry

A foot passenger is the default for a ferry leg; travelling with a car aboard is much higher because that passenger carries the vehicle's share.

7.6 Cruise

Cruise is the least precise factor in the whole calculator, and we mark it plainly as an estimate. We use 250 kg CO₂e per passenger per day, derived from research by the International Council on Clean Transportation (ICCT, theicct.org) (~250 g CO₂ per passenger-km for efficient ships, on a lifecycle basis). Cruise emissions vary enormously by ship, itinerary, cabin, and fuel (heavy fuel oil versus LNG), so no single figure can be exact. We deliberately use ICCT's defensible central estimate rather than the higher ~421 kg/day figure that circulates in advocacy writing, which is not a like-for-like measured value. Even as an estimate, 250 correctly conveys that a cruise is a very high-impact way to travel.

7.7 Scope and boundaries

• Trip results are per person (version 1.0 does not compute group totals).
• Food and activities are deliberately excluded — they are too granular and variable to estimate credibly, so the trip boundary is travel and accommodation only. We state this so the boundary is clear rather than implied.
• Flights include radiative forcing; all travel factors are DEFRA 2026 (cruise excepted, as noted). This matches the integrity line shown in the app: "Flights include radiative forcing · factors: DEFRA 2026."

Sources: flights, rail, ferry, car — UK DEFRA / DESNZ Government GHG Conversion Factors 2026 (published 11 June 2026); accommodation — DEFRA 2026 "Hotel stay" (underlying data: Cornell Hotel Sustainability Benchmarking); cruise — ICCT cruise emissions research (theicct.org), indicative.

8. Equivalencies

To make a tonnage tangible, ScopeSimple translates results into everyday equivalents — flights, trees, kilometres driven, and so on. Rather than always showing the same list, the app draws from a pool of 14 equivalencies and selects the handful most meaningful for the size of your result (a small footprint and a large one are best illustrated by different comparisons). These are illustrative comparisons, not precise scientific claims; several are explicitly indicative. The full pool and the factors used are below.

Factors are drawn from the app's equivalency constants (verified against the code). Items marked indicative are deliberately approximate — their purpose is to give a sense of scale, not an exact figure.

9. Limitations and simplifications (summary)

In the spirit of the Consultant Test, here is every material simplification in one place:

• Scope 1 + 2 only — Scope 3 is excluded (Section 1.3).
• One vintage per entry — no blending of factors across a calendar boundary; fiscal years use their start-year vintage (Section 5.3).
• AR6 GWP values applied uniformly, even where a national inventory cites AR5 (Section 5.4).
• Delivered-basis electricity (Section 4.1).
• Regional factors where available, national fallback otherwise (Section 4).
• Estimates, not assurance — results depend on the accuracy of your inputs and are not a certified or audited statement (Terms of Service).

We document these because hiding a simplification is how an estimate becomes misleading. Naming them is how it stays honest.

10. Questions

Questions about our methodology, or a source you'd like clarified:

ScopeSimple Technologies Inc.
Alberta, Canada
hello@scopesimple.com