Taylor Ko Calculator

Taylor KO Calculator

Calculate the Knockout Value (TKO Factor) for any Firearm Cartridge

Note: Use decimal format (e.g., .308, .458)

Taylor Knockout Value:

0.00

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Understanding the Taylor Knockout (TKO) Factor

The Taylor Knockout Factor (TKO) is a formula developed by John "Pondoro" Taylor, a famous big-game hunter and ivory poacher, to assess the "stopping power" of various cartridges against large, dangerous game (like elephants and buffalo). Unlike standard kinetic energy formulas that favor velocity, the TKO emphasizes bullet weight and caliber diameter.

The Taylor KO Formula

The calculation is straightforward but relies on imperial units used in the firearms industry:

TKO = (Bullet Weight in Grains × Velocity in fps × Diameter in inches) / 7000

The constant 7000 is used because there are exactly 7,000 grains in one pound, effectively turning the weight component into pounds for the final calculation.

TKO vs. Kinetic Energy

Kinetic energy (KE) squares the velocity (1/2mv²), meaning small, fast bullets often show higher energy than large, slow ones. Taylor argued that for stopping a charging animal, the "slap" or momentum of a large diameter bullet was more important than pure speed. This is why a .45-70 Government often has a higher TKO than a .223 Remington, even though the .223 travels much faster.

Real-World Example Calculation

Consider the legendary .375 H&H Magnum:

• Bullet Weight: 300 grains
• Velocity: 2,530 feet per second
• Diameter: 0.375 inches

Calculation: (300 × 2,530 × 0.375) / 7000 = 40.66 TKO

Common TKO Benchmarks

Cartridge	Typical TKO
.223 Remington	5 – 6
.30-06 Springfield	20 – 22
.45-70 Government	35 – 45
.416 Rigby	55 – 60
.577 Tyrannosaur	130+

function calculateTKOValue() { var weight = document.getElementById("bulletWeight").value; var velocity = document.getElementById("muzzleVelocity").value; var diameter = document.getElementById("bulletDiameter").value; var resultContainer = document.getElementById("tkoResultContainer"); var resultDisplay = document.getElementById("tkoValueDisplay"); var interpretation = document.getElementById("tkoInterpretation"); if (weight > 0 && velocity > 0 && diameter > 0) { var tko = (weight * velocity * diameter) / 7000; var finalTKO = tko.toFixed(2); resultDisplay.innerText = finalTKO; resultContainer.style.display = "block"; var category = ""; if (tko = 15 && tko = 30 && tko < 50) { category = "Large / Dangerous Game class."; } else { category = "Elephant / Heavy Thick-Skinned Game class."; } interpretation.innerText = "This load falls into the " + category; // Smooth scroll to result resultContainer.scrollIntoView({ behavior: 'smooth', block: 'nearest' }); } else { alert("Please enter valid positive numbers for weight, velocity, and diameter."); } }