📬 Email Carbon Footprint

Email carbon footprint 101 (friendly & practical)

This calculator is a lighthearted way to think about the invisible energy behind our inboxes. Emails are tiny, but sending, storing, and reading them uses electricity across a chain of devices and services—your phone or laptop, the networks that move data, and the data centres that keep messages available. When electricity is generated from fossil fuels, it produces greenhouse gases. We translate those indirect emissions into a single number called CO₂e (carbon dioxide equivalent) and compare it to playful metaphors like elephants or kettles boiled so the scale feels more tangible.

What’s actually counted here?

• Transfer energy: Moving data through the internet (ISPs, routers, cellular towers). Bigger attachments mean more data to move.
• Storage energy: Keeping emails on servers. Retaining mail for years costs more energy than clearing bulky threads.
• Device use (optional): Opening and reading messages on your device, which also draws power.
• Backups/copies: Cloud services keep redundant copies for reliability; the Copies factor knob lets you model that overhead.

How our two modes work

Simple mode uses per-email “ballpark” factors: a small value for text-only emails and a higher value for messages with attachments. It’s perfect for quick estimates when you just want to know, “Am I talking teacups or swimming pools?”
Advanced mode lets you tune the pieces: average message size, average attachment size, years stored, network energy per GB, data-centre storage energy per GB per year, grid carbon intensity (g CO₂ per kWh), device energy to read, and a copies/backups multiplier.

The friendly math

# Simple
total_grams = emails × [(1 - p_attach) × g_text + p_attach × g_attach]

# Advanced
avg_size_GB = ((1 - p_attach) × text_KB/1024
               + p_attach × (text_KB/1024 + attach_MB/1024))
total_GB     = emails × avg_size_GB × copies_factor
transfer_kWh = total_GB × network_kWh_per_GB
storage_kWh  = total_GB × storage_kWh_per_GB_per_year × years_stored
device_kWh   = emails × (device_Wh_per_email / 1000)
total_kWh    = transfer_kWh + storage_kWh + device_kWh
total_CO₂e   = total_kWh × grid_gCO₂_per_kWh

Limits to keep in mind

• Assumptions vary: Energy intensity and grid mix differ by country, time of day, and provider.
• Behavior matters: One huge attachment saved for years can outweigh thousands of tiny notes.
• It’s an estimate: We aim for clarity over false precision. Adjust the sliders to match your world.

Practical ways to shrink your inbox impact

• Unsubscribe from newsletters you rarely read.
• Send links, not large attachments (or compress files first).
• Set retention rules for bulky folders (e.g., auto-delete after 12–24 months).
• Archive locally if appropriate for long-term records you seldom access.
• Batch notifications so you receive fewer automated messages.

Why elephants? They’re just a playful metaphor. If you prefer something else—buses, blue whales, pizzas—we’ve kept the code modular so you can swap comparisons any time. 💛

Be kind to your inbox 💛

• Unsubscribe from newsletters you don’t read.
• Delete large attachments you don’t need; use links when possible.
• Auto-archive old threads, and consider shorter retention for bulky folders.