Weed Control & Herbicide Dosage Calculator
ANA›Life Services Authority›National Calculator Authority›Weed Control & Herbicide Dosage Calculator
.calc-container { max-width: 640px; margin: 2rem 0; padding: 1.5rem; background: #fff; border: 1px solid #ddd; border-radius: 8px; box-shadow: 0 1px 3px rgba(0,0,0,0.06); font-family: system-ui, -apple-system, sans-serif; } .calc-container h3 { font-family: Georgia, serif; font-size: 1.15rem; color: #1a1a1a; margin-bottom: 1rem; padding-bottom: 0.5rem; border-bottom: 2px solid var(--ac, #3d5a80); } .calc-row { display: flex; align-items: center; gap: 0.75rem; margin-bottom: 0.75rem; flex-wrap: wrap; } .calc-row label { min-width: 160px; font-size: 0.9rem; color: #333; font-weight: 500; } .calc-row input[type="number"], .calc-row select { flex: 1; min-width: 120px; max-width: 200px; padding: 0.5rem 0.6rem; border: 1px solid #ccc; border-radius: 4px; font-size: 0.9rem; font-family: system-ui, sans-serif; color: #1a1a1a; background: #fafaf8; } .calc-row input:focus, .calc-row select:focus { outline: none; border-color: var(--ac, #3d5a80); box-shadow: 0 0 0 2px rgba(26,74,138,0.12); } .calc-row .unit { font-size: 0.82rem; color: #888; min-width: 30px; } .calc-btn { display: inline-block; margin-top: 0.5rem; padding: 0.55rem 1.5rem; background: var(--ac, #3d5a80); color: #fff; border: none; border-radius: 4px; font-size: 0.9rem; font-weight: 600; cursor: pointer; font-family: system-ui, sans-serif; } .calc-btn:hover { opacity: 0.9; } .calc-result { margin-top: 1.25rem; padding: 1rem 1.25rem; background: #f0f6fc; border-left: 3px solid var(--ac, #3d5a80); border-radius: 0 6px 6px 0; display: none; } .calc-result.visible { display: block; } .calc-result-label { font-size: 0.78rem; text-transform: uppercase; letter-spacing: 0.06em; color: #666; margin-bottom: 0.25rem; } .calc-result-value { font-size: 1.6rem; font-weight: 700; color: var(--ac, #3d5a80); } .calc-result-detail { font-size: 0.85rem; color: #555; margin-top: 0.5rem; line-height: 1.5; } .calc-note { margin-top: 1rem; font-size: 0.8rem; color: #888; font-style: italic; } .calc-grid { display: grid; grid-template-columns: 1fr 1fr; gap: 0.75rem; margin-top: 0.75rem; } .calc-grid-item { padding: 0.6rem 0.8rem; background: #f8f9fa; border-radius: 4px; border: 1px solid #eee; } .calc-grid-item .label { font-size: 0.75rem; color: #888; text-transform: uppercase; letter-spacing: 0.04em; } .calc-grid-item .value { font-size: 1.1rem; font-weight: 600; color: #1a1a1a; } @media (max-width: 720px) { .calc-row { flex-direction: column; align-items: flex-start; gap: 0.3rem; } .calc-row label { min-width: auto; } .calc-row input[type="number"], .calc-row select { max-width: 100%; width: 100%; } .calc-grid { grid-template-columns: 1fr; } } .calc-chart { margin: 1rem 0; text-align: center; } .calc-chart svg { max-width: 100%; height: auto; } .calc-chart-legend { display: flex; flex-wrap: wrap; justify-content: center; gap: 0.6rem 1.2rem; margin-top: 0.6rem; font-size: 0.8rem; color: #555; } .calc-chart-legend span { display: inline-flex; align-items: center; gap: 0.3rem; } .calc-chart-legend i { display: inline-block; width: 10px; height: 10px; border-radius: 2px; font-style: normal; } .calc-related { max-width: 640px; margin: 2rem 0 1rem; padding: 1.25rem 1.5rem; background: #f8f9fa; border: 1px solid #e8e8e8; border-radius: 8px; } .calc-related h3 { font-family: Georgia, serif; font-size: 1rem; color: #1a1a1a; margin: 0 0 0.75rem; padding-bottom: 0.4rem; border-bottom: 2px solid var(--ac, #3d5a80); } .calc-related-list { list-style: none; padding: 0; margin: 0 0 0.75rem; display: grid; grid-template-columns: 1fr 1fr; gap: 0.4rem 1.5rem; } .calc-related-list li a { font-size: 0.88rem; color: var(--ac, #3d5a80); text-decoration: none; } .calc-related-list li a:hover { text-decoration: underline; } .calc-browse-all { margin: 0.5rem 0 0; font-size: 0.9rem; font-weight: 600; } .calc-browse-all a { color: var(--ac, #3d5a80); text-decoration: none; } .calc-browse-all a:hover { text-decoration: underline; } @media (max-width: 720px) { .calc-related-list { grid-template-columns: 1fr; } }
Weed Control & Herbicide Dosage Calculator
Calculate the exact amount of herbicide product needed for your field, accounting for area size, recommended active ingredient rate, and product concentration.
Field Area
Area Unit
Acres Hectares Square Feet Square Meters
Recommended Active Ingredient (AI) Rate (oz AI / acre)
Check your herbicide label for the recommended AI rate per acre.
Product Concentration (% AI by weight)
Example: Glyphosate 41% = 41. Found on the product label.
Product Density (lb/gal) (optional, default 8.34 for water-based)
Carrier Water Volume (gal / acre)
Typical range: 10–40 gal/acre for ground sprayers.
Calculate
function weeCalc() { // --- Gather inputs --- var area = parseFloat(document.getElementById('wee-area').value); var areaUnit = document.getElementById('wee-area-unit').value; var aiRate = parseFloat(document.getElementById('wee-ai-rate').value); // oz AI / acre var prodConc = parseFloat(document.getElementById('wee-product-conc').value); // % AI var prodDens = parseFloat(document.getElementById('wee-product-density').value); // lb/gal var waterRate = parseFloat(document.getElementById('wee-water-rate').value); // gal/acre
var resultDiv = document.getElementById('wee-result'); resultDiv.style.display = 'block';
// --- Validation --- var errors = []; if (isNaN(area) || area 100) errors.push("Product concentration must be between 0.01 and 100."); if (isNaN(prodDens) || prodDens 0) { resultDiv.className = 'calc-result calc-error'; resultDiv.innerHTML = 'Please fix the following errors:' + errors.map(function(e){ return ''; }).join('') + ''; return; }
// --- Unit conversion: everything to acres --- var areaAcres; if (areaUnit === 'acres') { areaAcres = area; } else if (areaUnit === 'hectares') { areaAcres = area * 2.47105; // 1 ha = 2.47105 acres } else if (areaUnit === 'sqft') { areaAcres = area / 43560.0; // 1 acre = 43,560 sq ft } else if (areaUnit === 'sqm') { areaAcres = area / 4046.856; // 1 acre = 4,046.856 sq m }
// --- Core Calculations ---
// 1. Total AI needed (oz) // Total AI (oz) = AI Rate (oz/acre) × Area (acres) var totalAI_oz = aiRate * areaAcres;
// 2. AI per gallon of product (oz AI / gal product) // AI per gal = (% AI / 100) × density (lb/gal) × 16 (oz/lb) var aiPerGalProduct = (prodConc / 100.0) * prodDens * 16.0; // oz AI / gal product
// 3. Product volume needed (gallons) // Product (gal) = Total AI (oz) / AI per gal product var productGal = totalAI_oz / aiPerGalProduct;
// 4. Product volume in fluid ounces and liters var productFlOz = productGal * 128.0; // 1 gal = 128 fl oz var productL = productGal * 3.78541; // 1 gal = 3.78541 L var productMl = productL * 1000.0;
// 5. Total water (carrier) needed // Total Water (gal) = Water Rate (gal/acre) × Area (acres) var totalWaterGal = waterRate * areaAcres; var totalWaterL = totalWaterGal * 3.78541;
// 6. Total spray volume (product + water) var totalSprayGal = productGal + totalWaterGal; var totalSprayL = totalSprayGal * 3.78541;
// 7. Product per 100 gal of water (mixing ratio check) // Product per 100 gal water = (productGal / totalWaterGal) × 100 var productPer100Gal = (productGal / totalWaterGal) * 100.0;
// 8. AI concentration in final spray mix (oz AI / gal spray) var aiConcentrationInSpray = totalAI_oz / totalSprayGal;
// --- Format helper --- function fmt(n, d) { return n.toFixed(d !== undefined ? d : 2); }
// --- Output --- resultDiv.className = 'calc-result calc-success'; resultDiv.innerHTML = '### ✓ Herbicide Dosage Results ' +
'' + '' + 'Parameter' + 'Value' + '' + 'Field Area' + '' + fmt(area,2) + ' ' + areaUnit + ' (' + fmt(areaAcres,4) + ' acres)' + 'Total Active Ingredient Needed' + '' + fmt(totalAI_oz,3) + ' oz AI (' + fmt(totalAI_oz/16,3) + ' lb AI)' + 'AI Concentration in Product' + '' + fmt(aiPerGalProduct,3) + ' oz AI / gal product' + '► Product Volume Needed' + '' + fmt(productGal,3) + ' gal | ' + fmt(productFlOz,1) + ' fl oz | ' + fmt(productL,2) + ' L (' + fmt(productMl,0) + ' mL)' + 'Carrier Water Needed' + '' + fmt(totalWaterGal,1) + ' gal (' + fmt(totalWaterL,1) + ' L)' + 'Total Spray Volume' + '' + fmt(totalSprayGal,1) + ' gal (' + fmt(totalSprayL,1) + ' L)' + 'Mixing Ratio' + '' + fmt(productPer100Gal,2) + ' gal product per 100 gal water' + 'AI Concentration in Spray Mix' + '' + fmt(aiConcentrationInSpray,4) + ' oz AI / gal spray' + '' +
'⚠ Always read and follow the herbicide label. The label is the law.
'; }
#### Formulas Used
1. Total Active Ingredient (AI) Needed: Total AI (oz) = AI Rate (oz AI/acre) × Area (acres)
2. AI per Gallon of Product: AI per gal product (oz AI/gal) = (% AI ÷ 100) × Product Density (lb/gal) × 16 (oz/lb)
3. Product Volume Needed: Product (gal) = Total AI (oz) ÷ AI per gal product (oz AI/gal)
4. Total Carrier Water: Water (gal) = Water Rate (gal/acre) × Area (acres)
5. Total Spray Volume: Total Spray (gal) = Product (gal) + Water (gal)
6. Mixing Ratio: Product per 100 gal water = (Product gal ÷ Water gal) × 100
Area Conversions: 1 hectare = 2.47105 acres | 1 acre = 43,560 ft² = 4,046.856 m²
#### Assumptions & References
- Default product density of 8.34 lb/gal is used for water-based liquid formulations (density of water). Oil-based or emulsifiable concentrates may differ (typically 8.0–9.5 lb/gal).
- Carrier water volume of 10–40 gal/acre is typical for ground boom sprayers; aerial application typically uses 2–5 gal/acre.
- This calculator applies to liquid herbicide formulations (EC, SL, SC, EW). Dry formulations (WP, WDG, DF) require weight-based calculations.
- Legal notice: Always comply with federal, state, and local pesticide regulations. The herbicide label is a legal document — it is a violation of federal law to use a pesticide inconsistent with its labeling (FIFRA, 7 U.S.C. §136).
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