.foaling-calculator-container {
font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
max-width: 800px;
margin: 0 auto;
background-color: #f9fdf9;
border: 1px solid #e0e0e0;
border-radius: 8px;
padding: 30px;
box-shadow: 0 4px 6px rgba(0,0,0,0.05);
}
.calc-header {
text-align: center;
margin-bottom: 25px;
color: #2c3e50;
}
.calc-row {
display: flex;
flex-wrap: wrap;
gap: 20px;
margin-bottom: 20px;
justify-content: center;
}
.calc-input-group {
flex: 1;
min-width: 250px;
max-width: 400px;
}
.calc-input-group label {
display: block;
margin-bottom: 8px;
font-weight: 600;
color: #34495e;
}
.calc-input-group input {
width: 100%;
padding: 12px;
border: 1px solid #bdc3c7;
border-radius: 6px;
font-size: 16px;
box-sizing: border-box;
}
.calc-btn-container {
text-align: center;
margin-top: 20px;
}
.calc-btn {
background-color: #27ae60;
color: white;
border: none;
padding: 14px 28px;
font-size: 18px;
border-radius: 6px;
cursor: pointer;
transition: background-color 0.3s;
font-weight: bold;
}
.calc-btn:hover {
background-color: #219150;
}
.result-box {
margin-top: 30px;
padding: 25px;
background-color: #fff;
border: 1px solid #dcdcdc;
border-radius: 8px;
display: none;
}
.result-header {
font-size: 22px;
color: #27ae60;
margin-bottom: 15px;
text-align: center;
border-bottom: 2px solid #ecf0f1;
padding-bottom: 10px;
}
.result-grid {
display: grid;
grid-template-columns: 1fr 1fr;
gap: 15px;
}
.result-item {
padding: 10px;
background: #f8f9fa;
border-radius: 5px;
}
.result-label {
font-size: 14px;
color: #7f8c8d;
margin-bottom: 5px;
}
.result-value {
font-size: 18px;
font-weight: bold;
color: #2c3e50;
}
.calendar-window {
margin-top: 20px;
padding: 15px;
background-color: #e8f6f3;
border-left: 5px solid #1abc9c;
border-radius: 4px;
}
.content-section {
margin-top: 40px;
line-height: 1.6;
color: #444;
}
.content-section h2 {
color: #2c3e50;
margin-top: 30px;
border-bottom: 1px solid #eee;
padding-bottom: 10px;
}
.content-section ul {
padding-left: 20px;
}
.content-section li {
margin-bottom: 10px;
}
@media (max-width: 600px) {
.result-grid {
grid-template-columns: 1fr;
}
}
function calculateFoalingDate() {
var dateInput = document.getElementById('breedingDate').value;
if (!dateInput) {
alert("Please select a valid Breeding Date first.");
return;
}
// Parse the input date (YYYY-MM-DD)
// Create date object set to noon to avoid timezone rollover issues
var parts = dateInput.split('-');
var year = parseInt(parts[0], 10);
var month = parseInt(parts[1], 10) – 1; // JS months are 0-11
var day = parseInt(parts[2], 10);
var breedingDate = new Date(year, month, day, 12, 0, 0);
// Validate date
if (isNaN(breedingDate.getTime())) {
alert("Invalid date entered.");
return;
}
// Calculation Constants
var AVG_GESTATION = 340;
var MIN_GESTATION = 320;
var MAX_GESTATION = 365;
// Calculate Dates
var avgDate = new Date(breedingDate);
avgDate.setDate(breedingDate.getDate() + AVG_GESTATION);
var minDate = new Date(breedingDate);
minDate.setDate(breedingDate.getDate() + MIN_GESTATION);
var maxDate = new Date(breedingDate);
maxDate.setDate(breedingDate.getDate() + MAX_GESTATION);
// Calculate Days Remaining
var today = new Date();
today.setHours(12, 0, 0, 0); // Normalize today
// Difference in time
var timeDiff = avgDate.getTime() – today.getTime();
// Difference in days (divide by milliseconds in a day)
var daysLeft = Math.ceil(timeDiff / (1000 * 3600 * 24));
var daysRemainingText = "";
if (daysLeft > 0) {
daysRemainingText = daysLeft + " Days";
} else if (daysLeft === 0) {
daysRemainingText = "Due Today!";
} else {
daysRemainingText = Math.abs(daysLeft) + " Days Overdue";
}
// Date Formatting Helper
function formatDate(d) {
var options = { weekday: 'short', year: 'numeric', month: 'long', day: 'numeric' };
return d.toLocaleDateString('en-US', options);
}
// Update DOM
document.getElementById('avgDueDate').innerHTML = formatDate(avgDate);
document.getElementById('minDueDate').innerHTML = formatDate(minDate);
document.getElementById('maxDueDate').innerHTML = formatDate(maxDate);
document.getElementById('daysRemaining').innerHTML = daysRemainingText;
document.getElementById('windowStart').innerHTML = formatDate(minDate);
document.getElementById('windowEnd').innerHTML = formatDate(maxDate);
// Show Result Box
document.getElementById('foalingResult').style.display = 'block';
}
Horse Foaling Date Calculator
Enter the date of breeding (covering) to estimate the due date.
Estimated Foaling Info
Average Due Date (340 Days)
–
Days Remaining
–
Earliest Viable (320 Days)
–
Latest Normal (365 Days)
–
Foaling Window: Most mares foal between and . Please ensure your foaling kit and vet contact details are ready by the "Earliest Viable" date.
Understanding Equine Gestation
Knowing when your mare is due to foal is essential for the health of both the mare and the foal. While the average gestation period for a horse is widely cited as 340 days (approximately 11 months), nature rarely adheres to a strict schedule.
How Accurate is the Due Date?
This calculator provides an estimate based on the standard 340-day average. However, a normal gestation range for horses is quite broad, typically falling between 320 and 365 days.
- Premature: Foals born before 320 days are often considered premature and may require veterinary intervention for lung development and immune support.
- Prolonged: It is not uncommon for mares, especially those foaling early in the year (January/February), to carry longer than 340 days due to shorter daylight hours.
Factors Influencing Gestation Length
- Season: Mares due in the spring often have slightly longer pregnancies than those due in the summer, as longer daylight hours can accelerate the final stages of pregnancy.
- Mare's History: Individual mares often establish their own patterns. If a mare consistently foals at 330 days, she is likely to do so again.
- Foal Gender: Statistical data suggests that colt foals (males) are often carried slightly longer (2-3 days on average) than fillies.
Signs of Impending Foaling
As the calculated date approaches, monitor your mare for these physical signs:
- Udder Development: The udder usually fills 2-4 weeks before foaling.
- Waxing: Small beads of colostrum (wax) may appear on the teat ends 6-48 hours before birth.
- Relaxation: Muscles around the tail head and vulva will relax significantly in the final days.
- Milk Calcium: Testing the calcium levels (pH) of the mare's milk is one of the most reliable ways to predict foaling within 24 hours.
Disclaimer: This calculator is for educational and planning purposes only. Always consult with your veterinarian regarding your mare's pregnancy health and specific medical needs.