Calculations & Formulas

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Food & Nutrition

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Daily Caloric Needs

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Age

Sex Male Female

Weight (kg)

Height (cm)

Activity Level Sedentary (little/no exercise) Light (1-3 days/week) Moderate (3-5 days/week) Active (6-7 days/week) Very Active (hard labor) Survival Mode (extreme)

Calculate

Formula (Mifflin-St Jeor):
Male: BMR = 10×weight + 6.25×height - 5×age + 5
Female: BMR = 10×weight + 6.25×height - 5×age - 161
TDEE = BMR × Activity Multiplier

Ration Planning

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Number of People

Days to Plan

Calories per Person/Day

Mode Normal Nutrition Survival Rations (75%) Minimal (50%)

Calculate

Food Supply Duration

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Total Calories in Storage

Number of People

Calories per Person/Day

Calculate

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Water Purification & Storage

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Daily Water Needs

Number of People

Climate Temperate Hot/Arid Cold Humid Tropical

Activity Level Sedentary Moderate Work Heavy Labor

Calculate

Standard Minimums:
Drinking: 2-3L/person/day
Cooking: 1-2L/person/day
Sanitation: 2-6L/person/day

Chlorine Purification

Water Volume (Liters)

Bleach Concentration (%) 5.25% (Standard) 6% 8.25% (Concentrated)

Water Clarity Clear Cloudy (double dose)

Calculate

Formula: 2 drops per liter for 5.25% bleach (clear water)
Wait 30 minutes before drinking. Should have slight chlorine smell.

Rainwater Collection

Roof Area (m²)

Rainfall (mm/month)

Collection Efficiency (%)

Calculate

Formula: Collection = Area × Rainfall × Efficiency
1mm rain on 1m² = 1 liter

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Energy & Power

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Solar Panel Output

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Panel Wattage (W)

Number of Panels

Peak Sun Hours/Day

System Efficiency (%)

Calculate

Formula: Daily kWh = Panels × Watts × Sun Hours × Efficiency / 1000

Battery Bank Sizing

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Daily Energy Need (kWh)

Days of Autonomy

Depth of Discharge (%)

Battery Voltage 12V 24V 48V

Calculate

Power Load Calculator

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Device	Watts	Hours/Day	Qty
				×
				×
				×

+ Add Device

Calculate Total Load

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Population Planning

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Population Growth Model

Initial Population

Growth Rate (%/year)

Years to Project

Carrying Capacity (0=unlimited)

Calculate

Workforce Allocation

Total Population

Working Age % (15-65)

Calculate

Housing Requirements

Population

Average Household Size

Floor Space per Person (m²)

Calculate

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Agriculture & Crop Yield

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Land Requirements Calculator

People to Feed

Calories per Person/Day

Primary Crop Potatoes (3000 cal/m²/year) Wheat (1200 cal/m²/year) Corn (1500 cal/m²/year) Rice (1000 cal/m²/year) Beans (800 cal/m²/year) Sweet Potato (2500 cal/m²/year)

Growing Method Open Field Raised Beds Greenhouse Intensive/Hydroponic

Calculate

Crop Yield Estimator

Land Area (m²)

Crop Type Potatoes (4 kg/m²) Wheat (0.4 kg/m²) Corn (0.8 kg/m²) Tomatoes (8 kg/m²) Dry Beans (0.25 kg/m²) Carrots (3 kg/m²)

Seasons per Year

Calculate

Livestock Feed Requirements

Animal Type Chickens Goats Pigs Cattle Sheep Rabbits

Number of Animals

Days

Calculate

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Construction & Materials

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Concrete Mix Calculator

Volume Needed (m³)

Mix Ratio 1:2:3 (Standard) 1:2:4 (Foundation) 1:3:6 (Mass Concrete) 1:1.5:3 (High Strength)

Calculate

Standard 1:2:3 mix:
1 part cement : 2 parts sand : 3 parts gravel
Water: ~0.5 × cement weight

Lumber Requirements

Structure Type Small Shed (3×3m) Cabin (5×5m) Small House (8×10m) Barn (6×8m)

Custom Floor Area (m²) - 0 for preset

Calculate

Foundation Volume

Perimeter Length (m)

Width (cm)

Depth (cm)

Calculate

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Logistics & Transportation

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Fuel Consumption Calculator

Vehicle Type Car (8 L/100km) SUV/Truck (12 L/100km) Heavy Truck (25 L/100km) Motorcycle (5 L/100km) Generator (35 L/day)

Distance (km) or Days for Generator

Load Factor (1-2)

Calculate

Carrying Capacity

Transport Method Human (backpack) - 25kg Human (porter) - 80kg Bicycle - 150kg Handcart - 400kg Pickup Truck - 1000kg Medium Truck - 5000kg Heavy Truck - 20000kg

Total Load to Move (kg)

Number of Transport Units

Calculate

Travel Time Estimator

Distance (km)

Mode of Travel Walking (5 km/h) Bicycle (15 km/h) Horse (25 km/h) Vehicle - Road (60 km/h) Vehicle - Off-road (30 km/h)

Terrain Difficulty Easy (paved/flat) Moderate (gravel/hills) Difficult (rough terrain) Extreme (mountain/jungle)

Calculate

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Medical & Dosage Tools

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Weight-Based Dosage Calculator

⚠️ For reference only. Always consult medical professionals when possible.

Patient Weight (kg)

Medication Ibuprofen (10mg/kg, max 800mg) Acetaminophen (15mg/kg, max 1000mg) Amoxicillin (25mg/kg, max 500mg) Diphenhydramine (1.25mg/kg, max 50mg)

Calculate

Oral Rehydration Calculator

Patient Weight (kg)

Dehydration Level Mild (thirsty, dry mouth) Moderate (dizzy, reduced urine) Severe (confusion, weak pulse)

Calculate

ORS Recipe (per liter):
6 level tsp sugar + ½ level tsp salt + 1 liter clean water

First Aid Supply Estimator

Group Size

Duration (days)

Risk Level Low (settled area) Medium (wilderness) High (conflict/disaster)

Estimate Supplies

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Communications & Signal

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Radio Range Estimator

Radio Type Handheld (0.5-5W) Mobile (10-50W) Base Station (50-100W) HF Radio (100W+)

Power (Watts)

Frequency Band VHF (30-300 MHz) UHF (300-3000 MHz) HF (3-30 MHz) CB (27 MHz)

Terrain Flat/Open Rolling Hills Urban Mountainous Dense Forest

Calculate

Antenna Length Calculator

Frequency (MHz)

Antenna Type Half-wave Dipole Quarter-wave Vertical Full-wave Loop 5/8 Wave

Calculate

Formula: Length = (300 / Frequency) × Wavelength Fraction
Speed of light ≈ 300,000 km/s

Line of Sight Distance

Antenna Height 1 (meters)

Antenna Height 2 (meters)

Calculate

Formula: Distance = 3.57 × (√h1 + √h2) km
Based on Earth's curvature

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Physics & Science Formulas

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Force Calculator (F = ma)

Mass (kg)

Acceleration (m/s²)

Calculate

Ohm's Law Calculator

Solve For Current (I) Voltage (V) Resistance (R) Power (P)

Voltage (V)

Resistance (Ω)

Current (A)

Calculate

Formulas:
V = I × R | I = V / R | R = V / I | P = V × I

Energy Calculators

Energy Type Kinetic Energy Potential Energy Heat Energy

Mass (kg)

Velocity (m/s)

Mass (kg)

Height (m)

Mass (kg)

Specific Heat (J/kg·K)

Temperature Change (°C)

Calculate

Pressure Calculator

Force (N)

Area (m²)

Calculate

Formula: P = F / A (Pascals)

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Unit Converter

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Universal Unit Converter

Category Length Weight/Mass Volume Temperature Area Energy Pressure Speed

Value

From

To

Convert

Quick Reference

Length

• 1 mile = 1.609 km
• 1 foot = 0.3048 m
• 1 inch = 2.54 cm
• 1 yard = 0.9144 m

Weight

• 1 pound = 0.4536 kg
• 1 ounce = 28.35 g
• 1 ton = 907.2 kg
• 1 stone = 6.35 kg

Volume

• 1 gallon = 3.785 L
• 1 quart = 0.946 L
• 1 cup = 236.6 mL
• 1 tbsp = 14.79 mL

Temperature

• °F = (°C × 9/5) + 32
• °C = (°F - 32) × 5/9
• K = °C + 273.15

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Arithmetic & Financial

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Percentage Calculator

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Calculate Type X% of Y X is what % of Y % change from X to Y

Value X

Value Y

Calculate

Ratio & Proportion

Ratio A : B

:

Total Amount to Divide

Calculate

Compound Interest

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Principal Amount

Annual Interest Rate (%)

Time (years)

Compounds per Year Annually Semi-annually Quarterly Monthly Daily

Calculate

Formula: A = P(1 + r/n)^(nt)

Inflation Adjustment

Original Amount

Annual Inflation Rate (%)

Years

Calculate

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Barter & Trade

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Barter Value Estimator

Item You Have Rice (1kg) - 1000 cal Beans (1kg) - 750 cal Ammo box (50 rds) Water filter First aid kit Matches (box) Flashlight + batteries

Quantity You Have

Item You Want Water filter Rice (1kg) - 1000 cal Beans (1kg) - 750 cal Ammo box (50 rds) First aid kit Matches (box) Flashlight + batteries

Calculate Fair Trade

Labor Hours Calculator

Task Type Unskilled labor Skilled trade work Technical/specialized Medical/critical skills

Hours Worked

Base Value per Hour (in rice kg equiv)

Calculate

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Vehicle & Mechanical

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2-Stroke Fuel Mix

Fuel Amount (liters)

Mix Ratio 25:1 (older equipment) 32:1 (general purpose) 40:1 (most chainsaws) 50:1 (modern equipment)

Calculate

Gear Ratio Calculator

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Drive Gear Teeth

Driven Gear Teeth

Input RPM

Calculate

Tire Size & Speed

Tire Width (mm)

Aspect Ratio (%)

Wheel Diameter (inches)

RPM (wheel)

Calculate

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Food Preservation

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Salt Curing Calculator

Meat Weight (kg)

Curing Method Light cure (2% salt) Standard cure (3.5%) Heavy cure (5%) Preservation cure (10%)

Calculate

Canning Pressure & Time

Food Type Vegetables (low acid) Meat chunks Fish Fruit (high acid) Stews/soups

Altitude (feet)

Jar Size Pint Quart

Calculate

Bread Dough Calculator

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Flour Weight (g)

Target Hydration (%) 55% (stiff dough) 60% (standard bread) 65% (soft bread) 70% (artisan) 80% (ciabatta)

Salt (% of flour)

Calculate

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Water Systems (Advanced)

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Well Output Calculator

Static Water Level (ft)

Drawdown Level (ft)

Pump Rate (GPM)

Recovery Time (hours)

Calculate

Pipe Flow Calculator

Pipe Diameter (inches) 1/2" 3/4" 1" 1-1/2" 2"

Pipe Length (ft)

Head Pressure (psi)

Calculate

Septic Tank Sizing

Number of Bedrooms

Daily Water Use per Person (gal)

People per Bedroom

Calculate

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Structural Engineering

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Roof Load Calculator

Roof Area (sq ft)

Snow Depth (inches)

Snow Type Fresh/Light (1 lb/in/sqft) Packed (2 lb/in/sqft) Wet/Heavy (3 lb/in/sqft) Ice (5 lb/in/sqft)

Calculate

Simple Beam Calculator

Wood Species Pine/Spruce (1000 psi) Douglas Fir (1200 psi) Oak (1500 psi) Engineered (2000 psi)

Beam Width (inches)

Beam Height (inches)

Span Length (feet)

Calculate

Rope & Cable Safe Load

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Rope Type Manila (600 lb/in²) Nylon (900 lb/in²) Polyester (1200 lb/in²) Steel cable (5000 lb/in²)

Rope Diameter (inches) 1/4" 3/8" 1/2" 5/8" 3/4" 1"

Safety Factor 4:1 (minimum) 5:1 (standard) 7:1 (lifting people) 10:1 (critical)

Calculate

Insulation Calculator

Wall Area (sq ft)

Insulation Type Fiberglass batt (R-3.2/in) Cellulose (R-3.7/in) Spray foam (R-6/in) Straw bale (R-1/in) Sawdust (R-2.5/in)

Thickness (inches)

Calculate

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Weather & Astronomy

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Wind Chill Calculator

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Temperature (°F)

Wind Speed (mph)

Calculate

Heat Index Calculator

Temperature (°F)

Relative Humidity (%)

Calculate

Dew Point Calculator

Temperature (°F)

Relative Humidity (%)

Calculate

Sun Position Calculator

Latitude (degrees)

Day of Year (1-365)

Hour (solar time)

Calculate

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Chemistry

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Solution Dilution (C1V1=C2V2)

Initial Concentration (%)

Initial Volume (mL)

Target Concentration (%)

Calculate

pH & Concentration

Calculate From pH value H+ concentration

Value

Calculate

Formula: pH = -log[H+]

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Security & Defense

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Basic Ballistics

Muzzle Velocity (fps)

Distance (yards)

Sight Height (inches)

Calculate

Sandbag Wall Calculator

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Wall Length (ft)

Wall Height (ft)

Wall Thickness (bags deep)

Calculate

Patrol Coverage

Perimeter (feet)

Guards per Shift

Walking Speed (ft/min)

Calculate

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Power Systems (Advanced)

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Wind Turbine Power

Rotor Diameter (m)

Wind Speed (m/s)

Efficiency (%)

Calculate

Formula: P = 0.5 × ρ × A × v³ × η
(air density ~1.225 kg/m³)

Water Wheel/Turbine Power

Flow Rate (L/s)

Head Height (m)

Efficiency (%)

Calculate

Formula: P = Q × H × ρ × g × η
(Q=flow, H=head, g=9.81)

Wire Gauge Calculator

Current (Amps)

Distance (one way, feet)

Voltage 12V DC 24V DC 48V DC 120V AC 240V AC

Max Voltage Drop (%)

Calculate