Current: inches = millimeters / 25.4
Both directions are supported:
inches = millimeters / 25.4millimeters = inches × 25.4Millimeter (mm) is an SI unit of length; inch (in) is an imperial unit. For neat display, values are typically rounded to 2–4 decimals.
inches = millimeters / 25.4';
} else {
inch.removeAttribute('readonly'); inch.type='number';
mm.setAttribute('readonly',''); mm.type='text'; mm.value='';
dirChip.textContent = 'Active: in → mm';
activeFormula.innerHTML = 'millimeters = inches × 25.4';
}
res.classList.remove('show');
}function convert(){
var v, out;
if(mode==='mm2in'){
v = parseFloat(mm.value); if(!isFinite(v) || v < 0) v = 0;
out = v / 25.4; // exact definition: 1 in = 25.4 mm
inch.value = fmt(out);
ans.textContent = fmt(v) + ' Millimeters = ' + fmt(out) + ' Inches';
} else {
v = parseFloat(inch.value); if(!isFinite(v) || v < 0) v = 0;
out = v * 25.4;
mm.value = fmt(out);
ans.textContent = fmt(v) + ' Inches = ' + fmt(out) + ' Millimeters';
}
res.classList.add('show');
}btnCalc.addEventListener('click', convert);
btnClear.addEventListener('click', function(){
mm.value = '';
inch.value = '';
res.classList.remove('show');
});
btnSwap.addEventListener('click', function(){ setMode(mode==='mm2in' ? 'in2mm' : 'mm2in'); });// Init
setMode('mm2in');
});
}
if(document.readyState==='loading') document.addEventListener('DOMContentLoaded', init); else init();
})();
Friends, measurement is an important part of our lives. Whether it’s buying furniture for your home, checking the size of a mobile screen, or verifying the dimensions of a car tire – measurement conversion comes in handy everywhere.
Millimeter (mm) and Inch (in) are both units of length measurement, but one comes from the Metric System while the other is part of the Imperial System. In India, most people use Metric units (mm, cm, meter), while in the US and UK, Inches and Feet are more common.
Definition: 1 Millimeter = 1/1000 meter (0.001 m).
$$\text{Inches} = \frac{\text{mm}}{25.4}$$ $$\text{mm} = \text{Inches} \times 25.4$$
| Millimeter (mm) | Inches (in) |
|---|---|
| 1 mm | 0.0394 in |
| 5 mm | 0.1969 in |
| 10 mm | 0.3937 in |
| 25 mm | 0.9843 in |
| 50 mm | 1.9685 in |
| 100 mm | 3.9370 in |
| 500 mm | 19.6850 in |
| 1000 mm | 39.3701 in |