⚖️ Comparison · Updated for 2026
MPH (miles per hour) vs KPH (kilometres per hour)
Side-by-side comparison, when-to-use-each guide, and instant conversion. Reviewed for 2026.
Quick answer: 1 mph = 1.609 kph. Mental shortcut: kph = mph × 1.6 (or add 60%). Most of the world uses kph on road signs; UK, US, Liberia and Myanmar use mph. Aviation uses knots, which is different again.
Decision guide — when to use which
Use MPH (miles per hour) when…
US, UK road signs and speedometers, Liberia, Myanmar.
Use KPH (kilometres per hour) when…
Most of the world. Republic of Ireland switched from mph to kph in 2005.
📊 Side-by-side comparison
| Aspect | MPH (miles per hour) | KPH (kilometres per hour) |
|---|---|---|
| UK motorway limit | 70 mph | 113 kph |
| Most EU motorway limits | ≈ 80-87 mph | 130-140 kph |
| Conversion | ×1.609 → kph | ×0.621 → mph |
| Speedometer dual | Most UK cars | Most European cars |
Frequently asked
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How fast is 100 mph in kph?
100 mph = 160.93 kph. Mental shortcut: multiply by 1.6 (so 100 mph ≈ 160 kph). Key speeds: 30 mph = 48 kph (urban UK limit), 70 mph = 113 kph (UK motorway limit), 100 mph = 161 kph, 120 mph = 193 kph. The UK uses mph for all road speeds; EU uses kph.
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Why does the UK still use mph?
The UK kept mph despite signing up to metric trade. Replacing road signs and speedometers across the country was costed at over £750 million in 2002 — politically unattractive ever since.
Reviewed for 2026. All conversion factors and historical references verified against official sources (ISO standards, government weights & measures legislation, IEC technical specifications). Built by a UK-based qualified primary teacher and FA Level 2 coach as part of 247QuickTools' free utility-tools project. We don't sell SEO links or accept paid placements in this content.