Finally Know What Your EV Journey Actually Costs
Winter range loss. Battery degradation. Your actual electricity rates. All factored in.
Coming March 2026 · £2.99 · No subscriptions
Know Before You Go
Enter a distance. See exactly what it costs.
Real Costs. Even in the Cold.
Other calculators ignore winter. We don't.
Try adjusting the controls below to see efficiency reduction
Based on research from DOE, AAA, and Recurrent Auto (30,000+ vehicles)
Head to Head
Pick two. See which wins.
Battery Intelligence
See how your battery holds up over time.
Set custom degradation rates per year. Based on Geotab EV Battery Health Study.
At a Glance
Beautiful widgets for any vehicle. Tap to dive deeper.
Built for Your Wrist
Select. Twist. Done.
Rectangular complication shows vehicle, distance & cost. Circular opens directly to any vehicle.
Seamlessly Synced
Powered by iCloud. Private by design.
Vehicles
Your saved vehicles sync automatically across all your devices
Settings
Charging rates, preferences, and customizations follow you everywhere
Compare
Pick up your vehicle comparisons right where you left off
Frequently Asked Questions
Everything you need to know about WattKit.
Can I compare different electric vehicles?
Yes! WattKit lets you compare two vehicles side-by-side, showing differences in journey costs, battery health projections, winter performance, and more. Export unlimited comparisons as professional PDFs to share with family, friends, or your local EV community.
How are EV journey costs calculated?
WattKit calculates your real journey costs by combining your vehicle's efficiency (miles per kWh), your actual electricity rates for home, work, and public charging, and factors in seasonal efficiency loss from cold weather. Simply enter the distance you want to travel, and WattKit shows you exactly what it will cost at each charging location.
How much does it cost to charge an electric car at home?
Home charging costs depend on your electricity tariff and region. Many EV owners take advantage of off-peak tariffs to charge overnight at lower rates. WattKit lets you enter your exact home, work, and public charging rates — in your local currency — so you always know your true costs, not national averages.
How does cold weather affect EV range?
Cold weather can reduce EV range by 15-45% depending on temperature and whether your vehicle has a heat pump. WattKit's winter mode calculates this automatically based on research from the DOE, AAA, and Recurrent Auto (studying 30,000+ vehicles). Select your conditions — mild, typical, or severe winter — and WattKit adjusts your cost calculations accordingly.
How much does EV battery degrade each year?
Battery degradation varies by chemistry. LFP batteries retain about 93% capacity after 5 years, while NMC and NCA batteries retain around 87-88%. WattKit models degradation year-by-year based on real-world studies, showing you projected range and costs over your ownership period. All research sources are linked directly within the app if you want to dive deeper.
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