Gas Rate Conversion Calculator
.gas-calculator-container {
max-width: 800px;
margin: 0 auto;
padding: 20px;
font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
background: #f9f9f9;
border-radius: 8px;
box-shadow: 0 2px 10px rgba(0,0,0,0.05);
}
.gas-calculator-container h2 {
text-align: center;
color: #2c3e50;
margin-bottom: 25px;
}
.gc-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 20px;
}
@media (max-width: 600px) {
.gc-grid {
grid-template-columns: 1fr;
}
}
.gc-input-group {
margin-bottom: 15px;
}
.gc-input-group label {
display: block;
margin-bottom: 5px;
font-weight: 600;
color: #444;
font-size: 0.9em;
}
.gc-input-group input, .gc-input-group select {
width: 100%;
padding: 10px;
border: 1px solid #ddd;
border-radius: 4px;
font-size: 16px;
box-sizing: border-box;
}
.gc-input-group input:focus, .gc-input-group select:focus {
border-color: #3498db;
outline: none;
box-shadow: 0 0 5px rgba(52, 152, 219, 0.3);
}
.gc-btn-group {
grid-column: 1 / -1;
display: flex;
gap: 10px;
margin-top: 10px;
}
.gc-btn {
flex: 1;
padding: 12px;
border: none;
border-radius: 4px;
font-size: 16px;
font-weight: bold;
cursor: pointer;
transition: background 0.2s;
}
.gc-btn-calc {
background-color: #e67e22;
color: white;
}
.gc-btn-calc:hover {
background-color: #d35400;
}
.gc-btn-reset {
background-color: #95a5a6;
color: white;
}
.gc-btn-reset:hover {
background-color: #7f8c8d;
}
.gc-results {
grid-column: 1 / -1;
background: #fff;
padding: 20px;
border-radius: 4px;
border: 1px solid #e1e1e1;
margin-top: 20px;
display: none;
}
.gc-result-row {
display: flex;
justify-content: space-between;
align-items: center;
padding: 10px 0;
border-bottom: 1px solid #eee;
}
.gc-result-row:last-child {
border-bottom: none;
}
.gc-result-label {
color: #555;
font-weight: 500;
}
.gc-result-value {
font-weight: bold;
color: #2c3e50;
font-size: 1.1em;
}
.gc-highlight {
color: #e67e22;
font-size: 1.3em;
}
.gc-article {
margin-top: 40px;
padding: 20px;
background: #fff;
border-radius: 8px;
line-height: 1.6;
color: #333;
border: 1px solid #eee;
}
.gc-article h3 {
color: #2c3e50;
margin-top: 25px;
border-bottom: 2px solid #f0f0f0;
padding-bottom: 10px;
}
.gc-article p {
margin-bottom: 15px;
}
.gc-article ul {
margin-bottom: 15px;
padding-left: 20px;
}
.gc-article li {
margin-bottom: 8px;
}
.gc-note {
font-size: 0.85em;
color: #666;
margin-top: 5px;
}
Gas Rate Conversion Calculator
Gas Meter Type
Metric (m³)
Imperial (ft³)
Time Taken (Seconds)
Calculate Heat Input
Reset
Calculation Results
Gross Heat Input (kW):
–
Gross Heat Input (BTU/hr):
–
Gas Flow Rate (m³/hr):
–
Gas Flow Rate (ft³/hr):
–
Understanding Gas Rate Calculation
Accurately calculating the gas rate (or heat input) of an appliance is a critical task for heating engineers and gas technicians. This process ensures that a boiler, fire, or cooker is burning the correct amount of gas as specified by the manufacturer, ensuring both efficiency and safety.
Metric vs. Imperial Gas Meters
Gas meters generally come in two formats, and the calculation method differs slightly for each:
Metric Meters (m³): These measure volume in cubic meters. The test dial usually measures 0.010 m³ per revolution (though older or larger meters may use 0.005 m³ or 0.1 m³).Imperial Meters (ft³): These measure volume in cubic feet. The standard test dial represents 1 cubic foot per revolution.
The Calculation Formulas
To determine the energy output in Kilowatts (kW), we first determine the volumetric flow rate and then apply the calorific value of the gas.
1. Calculate Flow Rate (m³/hr)
For Metric meters:Rate (m³/hr) = (3600 × Test Volume) ÷ Seconds
For Imperial meters:Rate (ft³/hr) = (3600 × Test Volume) ÷ SecondsThen convert to metric: m³/hr = ft³/hr × 0.0283
2. Calculate Heat Input (kW)
Once the flow rate is known in cubic meters per hour, use the Calorific Value (CV) of the gas (typically around 38.0 to 40.0 MJ/m³ for natural gas).
Heat Input (kW) = (Flow Rate (m³/hr) × Calorific Value) ÷ 3.6
Why is this important?
Safety: An appliance that is "over-gassed" (burning too much gas) can produce excessive carbon monoxide and overheat components.
Efficiency: An appliance that is "under-gassed" will not reach its designed output, leading to poor performance and slower heating times.
function updateDefaultVolume() {
var type = document.getElementById('meterType').value;
var volInput = document.getElementById('testVolume');
var note = document.getElementById('volNote');
if (type === 'metric') {
volInput.value = "0.01";
note.innerText = "Default for Metric is usually 0.010 m³";
} else {
volInput.value = "1";
note.innerText = "Default for Imperial is usually 1 ft³";
}
}
function calculateGasRate() {
// 1. Get input values
var meterType = document.getElementById('meterType').value;
var testVolume = parseFloat(document.getElementById('testVolume').value);
var timeSecs = parseFloat(document.getElementById('timeSecs').value);
var cv = parseFloat(document.getElementById('calorificValue').value);
// 2. Validation
if (isNaN(testVolume) || testVolume <= 0) {
alert("Please enter a valid test volume.");
return;
}
if (isNaN(timeSecs) || timeSecs <= 0) {
alert("Please enter a valid time in seconds (greater than 0).");
return;
}
if (isNaN(cv) || cv <= 0) {
alert("Please enter a valid Calorific Value.");
return;
}
// 3. Calculation Logic
var flowRateM3 = 0;
var flowRateFt3 = 0;
if (meterType === 'metric') {
// Formula: (3600 * vol) / time
flowRateM3 = (3600 * testVolume) / timeSecs;
// Convert m3 to ft3 for display (1 m3 = 35.3147 ft3)
flowRateFt3 = flowRateM3 * 35.3147;
} else {
// Imperial
// Formula: (3600 * vol) / time = ft3/hr
flowRateFt3 = (3600 * testVolume) / timeSecs;
// Convert ft3 to m3 for energy calc (1 ft3 = 0.0283168 m3)
flowRateM3 = flowRateFt3 * 0.0283168;
}
// Energy Calculation
// kW = (m3/hr * CV) / 3.6
var kw = (flowRateM3 * cv) / 3.6;
// BTU Calculation
// 1 kW = 3412.14 BTU/hr
var btu = kw * 3412.14;
// 4. Display Results
document.getElementById('resKW').innerText = kw.toFixed(2) + " kW";
document.getElementById('resBTU').innerText = Math.round(btu).toLocaleString() + " BTU/hr";
document.getElementById('resM3').innerText = flowRateM3.toFixed(3) + " m³/hr";
document.getElementById('resFt3').innerText = flowRateFt3.toFixed(2) + " ft³/hr";
document.getElementById('resultsArea').style.display = 'block';
}
function resetGasCalc() {
document.getElementById('meterType').value = 'metric';
document.getElementById('testVolume').value = '0.01';
document.getElementById('timeSecs').value = '120';
document.getElementById('calorificValue').value = '39.0';
document.getElementById('resultsArea').style.display = 'none';
updateDefaultVolume();
}