58 free agriculture calculators and tools. Solve real-world agriculture problems instantly with accurate, step-by-step results on ApexCalc.
Calculate fertilizer application rates based on soil test results, crop requirements, and field area. Supports N-P-K nutrients and multi-nutrient blends.
Calculate reference evapotranspiration (ETâ‚€) using the FAO-56 Penman-Monteith equation, the gold standard for irrigation scheduling and crop water requirement estimation.
Schedule field irrigation using the checkbook water balance method, tracking daily ET use and rainfall to determine when and how much to irrigate.
Calculate drip emitter flow rate, run time, and water application depth for micro-irrigation systems using emitter discharge, spacing, and row spacing parameters.
Calculate the average precipitation rate (mm/hr) of a sprinkler irrigation system based on nozzle flow rate and sprinkler spacing to ensure optimal water distribution.
Estimate the annual and monthly water budget for landscaped areas, accounting for plant type, landscape coefficient, irrigated area, and local reference ET.
Calculate the daily and weekly evapotranspiration-based water requirement for turfgrass areas, supporting smart irrigation controller programming.
Calculate the current soil moisture deficit (SMD) compared to field capacity to determine irrigation timing and application depth.
Calculate the leaching requirement (LR) to flush excess salts below the root zone, preventing salt stress and yield reduction in irrigated crops.
Calculate the optimal spacing between subsurface drainage tiles using the Hooghoudt or Kirkham equation to achieve target water table drawdown in agricultural fields.
Determine optimal installation depth for subsurface tile or perforated pipe drains to maximise hydraulic efficiency and minimise frost damage.
Convert bulk soil electrical conductivity (ECa) readings to saturated paste extract ECe to assess salinity risk and crop yield impact using USDA salinity thresholds.
Calculate soil CEC and the contribution from organic matter and clay fractions to understand nutrient-holding capacity and fertiliser management needs.
Calculate the percentage saturation of base cations (Ca, Mg, K, Na) on soil exchange sites relative to total CEC for soil fertility and pH management.
Convert between soil organic matter (SOM) percentage and soil organic carbon (SOC) content using the Van Bemmelen factor and Walkley-Black correction.
Calculate the fertilizer product application rate (kg/ha or lbs/acre) required to supply a target nutrient rate, accounting for nutrient content and efficiency.
Calculate the gypsum (CaSO₄·2H₂O) application rate required to reclaim sodic soils by replacing exchangeable sodium with calcium and reducing ESP below 15%.
Convert herbicide product label rates to active ingredient per hectare and calibrate field application volume for boom or knapsack sprayers.
The pre-harvest interval is the number of days a label requires between the last application and harvest. This page counts the days from the application date and reports whether the interval has elapsed for the product and rate used.
Calculate the worker re-entry interval (REI) expiry time after pesticide application to protect agricultural workers from pesticide exposure per EPA Worker Protection Standard.
Calculate the action threshold pest density above which pest control is economically justified, using crop value, control cost, and pest injury coefficients.
Calculate the Economic Injury Level — the minimum pest population density that causes economic damage equal to the cost of pest control — to guide IPM decisions.
Calculate the Actual Production History (APH) yield used as the basis for US federal crop insurance coverage, averaging up to 10 years of yield records.
Convert grain weight at field moisture to a standard moisture basis (corn 15.5%, soybeans 13%, wheat 13.5%) for accurate bushel weights and marketing.
Calculate price discounts or premiums based on grain test weight deviations from USDA grade standards for corn, soybeans, wheat, and other commodities.
Estimate the cost per bushel to dry grain from field moisture to storage moisture, accounting for propane or natural gas price, drying efficiency, and shrink loss.
Estimate dry matter and economic losses from grain storage based on storage conditions, duration, temperature, and moisture using FAO and USDA storage loss models.
Calculate the maximum grain storage capacity of a cylindrical grain bin in bushels and metric tonnes based on bin diameter, eave height, and peak overfill.
Size an aeration fan for a grain storage bin based on target airflow rate (CFM/bu), grain type, bin diameter, and grain depth to maintain quality during storage.
Estimate the temperature rise through a grain mass during aeration based on airflow rate, ambient temperature, and grain depth to optimise cooling management.
Estimate pre-harvest and harvest machinery losses (kernels/seeds per unit area) and convert to bushels per acre to quantify combine and header adjustment needs.
Estimate standing forage yield in dry matter tonnes per hectare from canopy height, density, and forage type to plan harvest timing and livestock allocation.
Estimate silage packing density and total DM stored in a bunker or pile silo from dimensions, filling rate, and target packing density to minimise fermentation losses.
Calculate rangeland or pasture carrying capacity in Animal Unit Months (AUMs) based on forage production, utilisation rate, and animal unit equivalence.
Calculate the appropriate stocking rate (animals per hectare or AUs per acre) for a given paddock area and forage availability to balance production and pasture health.
Calculate the optimal paddock size and number of paddocks for a rotational grazing system based on herd size, forage growth rate, grazing period, and rest period.
Calculate the feed conversion ratio (FCR) for livestock or poultry, measuring kilograms of feed consumed per kilogram of live weight gained.
Estimate daily water intake requirements for cattle, sheep, poultry, and horses based on species, weight, production stage, and ambient temperature.
Calculate expected dressing percentage, carcass weight, and retail cut yield from live animal weight for beef, pork, and lamb.
Calculate expected yield of individual meat cuts (loin, round, chuck, rib) from a beef, pork, or lamb carcass based on weight and USDA grade or carcass composition.
Calculate hen-day and hen-housed egg production rates, feed cost per dozen eggs, and flock efficiency metrics for commercial or small flock poultry operations.
Estimate the number of days required for broiler chickens to reach target market weight based on breed, average daily gain, and target live weight.
Calculate the feed conversion ratio (FCR) for fish and shrimp aquaculture, accounting for metabolic efficiency, wet weight gain, and uneaten feed losses.
Calculate optimal fish stocking density for a pond or tank aquaculture system based on water volume, target harvest weight, aeration capacity, and oxygen demand.
Calculate expected shrimp harvest yield (kg/ha/cycle) and survival rate from stocking density, pond area, target size, and historical survival data.
Calculate the peak heating load for a greenhouse in BTU/hr based on glazing material, greenhouse dimensions, inside/outside temperature differential, and infiltration.
Calculate Daily Light Integral (DLI) provided by grow lights and determine if supplemental light is sufficient for crop light requirements in controlled environment agriculture.
Calculate the required ventilation rate (CFM or m³/hr) for a greenhouse to control temperature, humidity, and CO₂ concentration during summer peak conditions.
Determine whether current soil temperature meets germination minimums for a selected crop and estimate days to germination using base temperature and thermal time models.
Calculate the target plant population per acre or hectare from row spacing, in-row spacing, and desired stand for optimum crop yield.
Convert between row spacing configuration, seeds per unit length, and total plant count per field area for planting prescriptions and yield component analysis.
Calculate crop evapotranspiration (ETc) using FAO Irrigation and Drainage Paper 56 methodology. Computes reference ET0 (Penman-Monteith), crop coefficient (Kc) adjustments, and net irrigation requirement by growth stage.
Calculate daily soil water balance for agricultural fields using precipitation, irrigation, evapotranspiration, and drainage. Determines soil moisture deficit, readily available water (RAW), and irrigation trigger timing per FAO-56 guidelines.
Calculate fertilizer blend ratios to achieve target NPK application rates from available fertilizer products. Converts nutrient removal goals to product application rates, accounts for nutrient analysis, and estimates material costs per acre or hectare.
Calculate agricultural lime requirement to raise soil pH to target level using the Mehlich buffer pH method or Shoemaker-McLean-Pratt (SMP) buffer test. Accounts for limestone CCE (calcium carbonate equivalent) and fineness factor.
Estimate maximum crop yield potential from solar radiation, temperature, and water availability using the FAO AEZ (Agro-Ecological Zones) biomass calculation method. Compares attainable yield to water-limited and radiation-limited theoretical maximums.
Calculate and apply harvest index (HI) to estimate grain or fruit yield from above-ground biomass measurements. Compare HI values against crop-specific baselines and assess yield optimization from crop selection.
Calculate optimal seeding rate (seeds/ha or lbs/acre) from target plant population, seed germination percentage, field emergence factor, and thousand seed weight. Adjusts for seed lot quality and field conditions per crop-specific recommendations.