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Convert metres, kilometres, miles, feet, inches and yards using exact international definitions — plus steps-to-distance based on your own height rather than one assumed average.
Enter your height and the step length fills in automatically (about 0.415 × height). A 150 cm person takes roughly 27% more steps per kilometre than a 190 cm person, so the default is only a starting point.
Pedometers, phones and fitness trackers all report steps, and converting them to distance is one of the most common reasons people look for a length converter. The problem is that almost every tool uses a single "average" step and never mentions it.
| Height | Step length | Steps per km | 10,000 steps |
|---|---|---|---|
| 150 cm (4′11″) | 0.622 m | 1606 | 6.22 km |
| 155 cm (5′1″) | 0.643 m | 1555 | 6.43 km |
| 160 cm (5′3″) | 0.664 m | 1506 | 6.64 km |
| 165 cm (5′5″) | 0.685 m | 1460 | 6.85 km |
| 170 cm (5′7″) | 0.705 m | 1417 | 7.05 km |
| 175 cm (5′9″) | 0.726 m | 1377 | 7.26 km |
| 180 cm (5′11″) | 0.747 m | 1339 | 7.47 km |
| 185 cm (6′1″) | 0.768 m | 1303 | 7.68 km |
| 190 cm (6′3″) | 0.788 m | 1268 | 7.88 km |
Based on the common estimate that step length is roughly 0.415 × height. Individual gait varies further.
Two further things worth knowing. A step is one foot landing; a stride is two steps, so a stride length is roughly double. And step length changes with pace — walking briskly lengthens it, strolling shortens it — so treat any figure as an estimate rather than a measurement. If you want it accurate, walk a measured 100 m and count.
The metre is no longer a physical object. Since 1983 it has been defined as the distance light travels in a vacuum in 1/299,792,458 of a second — a definition chosen because the speed of light is constant everywhere, so anyone with the right equipment can reproduce it.
| Unit | In metres | Exact? |
|---|---|---|
| inch | 0.0254 | Yes, by definition |
| foot | 0.3048 | Yes — 12 inches |
| yard | 0.9144 | Yes — 3 feet |
| mile | 1,609.344 | Yes — 1,760 yards |
| nautical mile | 1,852 | Yes, by international agreement |
Walk onto any Australian building site and every dimension will be in millimetres — 2400, 90, 450 — never centimetres. This is deliberate, and it is worth understanding if you are working from plans.
| Common Australian dimension | In millimetres | Imperial origin |
|---|---|---|
| Standard ceiling height | 2400 mm | Close to the old 8 feet (2438 mm) |
| Stud spacing | 450 or 600 mm | Replaced 18 and 24 inch spacings |
| Plasterboard sheet | 1200 × 2400 mm | Metricated 4 × 8 feet |
| Standard door | 820 × 2040 mm | Metric sizing |
| Brick (nominal) | 230 × 110 × 76 mm | Metric standard |
A source of genuine confusion when reading overseas building content.
| System | Named as | Actual size |
|---|---|---|
| Australian | 90 × 45 | 90 × 45 mm — the name is the size |
| United States | 2 × 4 | 1½ × 3½ inches = 38 × 89 mm |
American timber is named for its rough sawn dimensions before drying and dressing, so a "two by four" has not been two inches by four inches in a very long time. Australian dressed timber is named for what it actually measures. The amusing result is that a US 2×4 at 89 mm and an Australian 90×45 at 90 mm are almost the same board — they just describe it differently.
Plenty of Australians still think of their height in feet and inches even though every official record uses centimetres.
| Feet & inches | Centimetres | Metres |
|---|---|---|
| 5′0″ | 152.4 cm | 1.52 m |
| 5′2″ | 157.5 cm | 1.57 m |
| 5′4″ | 162.6 cm | 1.63 m |
| 5′6″ | 167.6 cm | 1.68 m |
| 5′8″ | 172.7 cm | 1.73 m |
| 5′10″ | 177.8 cm | 1.78 m |
| 6′0″ | 182.9 cm | 1.83 m |
| 6′2″ | 188.0 cm | 1.88 m |
| 6′4″ | 193.0 cm | 1.93 m |
Going the other way, divide centimetres by 2.54 for total inches, then divide by 12 for feet with the remainder as inches. Watch the rounding — 175 cm is 5′8.9″, which most people round to 5′9″.
The nautical mile looks like an arbitrary 1,852 m until you know where it came from — and then it is the most sensible unit on the list.
For navigation this is enormously convenient: a degree of latitude on a chart is exactly 60 nautical miles, so distance can be read straight off the latitude scale without any conversion. The knot follows from it — one nautical mile per hour, or 1.852 km/h exactly.
Every conversion here in one place — the formula, and what it gives for a value of one.
| Conversion | Formula | 1 unit gives |
|---|---|---|
| cm → inches | cm ÷ 2.54 | 0.393701 in |
| inches → cm | in × 2.54 | 2.54 cm |
| mm → inches | mm ÷ 25.4 | 0.0393701 in |
| metres → feet | m ÷ 0.3048 | 3.28084 ft |
| feet → metres | ft × 0.3048 | 0.3048 m |
| km → miles | km × 0.621371 | 0.621371 mi |
| miles → km | mi × 1.609344 | 1.609344 km |
| yards → metres | yd × 0.9144 | 0.9144 m |
| metres → yards | m ÷ 0.9144 | 1.09361 yd |
| feet & inches → cm | (ft × 12 + in) × 2.54 | 5′10″ = 177.8 cm |
| nautical → statute miles | nmi × 1.15078 | 1.15078 mi |
| Where you meet it | Conversion needed |
|---|---|
| Screen and monitor sizes | Inches, diagonally — a 55″ TV is 139.7 cm corner to corner |
| Wheels and tyres | Rim in inches, tyre width in millimetres, on the same tyre |
| Overseas road signs | Miles to kilometres — multiply by 1.6 |
| Running and athletics | Marathon is 42.195 km, or 26.219 miles |
| Swimming pools | Olympic 50 m; older Australian pools sometimes 55 yards |
| Fishing and boating | Depth in metres, distance in nautical miles |
| Plumbing fittings | Pipe threads still sized in inches |
How many centimetres are in an inch?
Exactly 2.54 centimetres. This is a definition rather than a measurement — since the international yard and pound agreement of 1959, the inch has been defined as precisely 25.4 millimetres, which makes every inch-to-metric conversion exact.
How many kilometres is 10,000 steps?
It depends on your height, and the range is wide. At about 0.415 × height for step length, someone 150 cm tall covers roughly 6.2 km while someone 190 cm covers about 7.9 km. The commonly quoted figure of 7.5 to 8 km assumes a fairly tall walker. Enter your height in the calculator above for a figure that fits you.
How do I convert feet and inches to centimetres?
Multiply the feet by 12, add the inches, then multiply by 2.54. So 5 feet 9 inches is (5 × 12 + 9) × 2.54 = 69 × 2.54 = 175.3 cm. Going the other way, divide centimetres by 2.54 to get total inches, then divide by 12 for feet with the remainder as inches.
How many feet are in a metre?
About 3.2808 feet, or 3 feet 3.37 inches. For rough mental work, a metre is a bit over three feet — adding 10% to a figure in yards gets you close to metres, since a yard is 0.9144 m.
How many kilometres are in a mile?
Exactly 1.609344 kilometres. For quick estimates, multiply miles by 1.6, or multiply by 8 and divide by 5. Going the other way, a kilometre is 0.621371 miles, so multiplying kilometres by 0.6 gets you close.
What is a nautical mile and why is it different?
A nautical mile is 1,852 metres — about 15% longer than a statute mile. It equals one minute of latitude, so 60 nautical miles is one degree. That makes it extremely convenient for navigation, because distance can be read directly off a chart's latitude scale. A knot is one nautical mile per hour, or exactly 1.852 km/h.
Why does Australian building use millimetres instead of centimetres?
Because whole millimetres avoid decimal points, and decimal points are where mistakes happen. A dimension written as 2400 cannot be misread, whereas 240 cm or 2.4 m invites a slipped decimal or hides the intended precision. Millimetres also match the accuracy trades actually work to.
Is an 8-foot ceiling the same as 2400 mm?
No — 8 feet is 2438 mm, so a genuine 8-foot ceiling is 38 mm taller than the standard modern 2400 mm. It matters when ordering plasterboard or lining for an older house, because standard 2400 mm sheets will leave a gap.
Why is a US 2x4 not 2 inches by 4 inches?
Because American timber is named for its rough sawn size before drying and dressing. A finished 2×4 measures 1½ by 3½ inches, which is 38 × 89 mm. Australian dressed timber is named for its actual size, so a 90 × 45 really is 90 mm by 45 mm — nearly the same board, described honestly.
What is the SI unit of length?
The metre. Since 1983 it has been defined as the distance light travels in a vacuum in 1/299,792,458 of a second. Every other length unit, metric or imperial, is now defined in terms of it.
What is the difference between a step and a stride?
A step is one foot landing; a stride is a full cycle of both feet, so one stride equals two steps. Step length is therefore about half stride length. Fitness trackers almost always count steps rather than strides, so use step length when converting their output.
How accurate are step-based distance estimates?
Reasonable for tracking trends, poor for precise distance. Step length changes with pace, terrain, footwear and fatigue, and the height-based estimate is only a starting point. For a better figure, walk a measured 100 metres, count your steps, and divide — that personal number will beat any formula.
Most length conversion is genuinely exact, because imperial units are defined in metric terms. An inch is 25.4 mm, full stop — no approximation involved.
The exception is anything involving a human body. Steps, strides and paces are estimates dressed up as units, and the honest thing is to say so and let you supply your own figure rather than quietly assuming everyone is the same height.
For other measurement types, the unit converter handles ten categories in one place, and there are dedicated pages for weight, temperature and volume.