Bullet Weight to Caliber Comparison Calculator
Compare two bullets side by side using caliber, bullet weight and velocity. See sectional density, kinetic energy, momentum and frontal area at a glance.
Compare Two Bullets
Enter the bullet diameter, weight and velocity for two loads. The calculator works out how they compare on density, energy and momentum so you can see how weight and caliber interact.
Bullet Comparison
Load A against Load B.
Understanding the Numbers
What each result tells you
Sectional Density
Weight in pounds divided by diameter squared. It shows how much mass sits behind a bullet’s frontal area, and generally relates to how well it retains momentum.
Kinetic Energy
Calculated from weight and velocity squared, so speed has a big effect. Fast, lighter bullets can match the energy of slower, heavier ones.
Momentum
Weight multiplied by velocity. Heavier bullets gain an advantage here, so comparing momentum alongside energy gives a fuller picture.
Caliber and Frontal Area
A wider bullet has more frontal area. For the same weight, a larger caliber lowers sectional density, while a smaller caliber raises it.
Caliber & Sectional Density Examples
Example bullet weights and their sectional density for a range of common bullet diameters. Figures are illustrative.
| Bullet Diameter | Metric Equivalent | Example Weight | Sectional Density |
|---|---|---|---|
| .224 in | 5.69 mm | 55 grains | 0.157 |
| .243 in | 6.17 mm | 100 grains | 0.242 |
| .264 in | 6.71 mm | 140 grains | 0.287 |
| .308 in | 7.82 mm | 168 grains | 0.253 |
| .338 in | 8.59 mm | 250 grains | 0.313 |
| .355 in | 9.02 mm | 124 grains | 0.141 |
| .452 in | 11.48 mm | 230 grains | 0.161 |
Bullet Comparison Calculator FAQ
Answers to the most common questions about bullet weight, caliber, energy and sectional density.
Sectional density is a bullet’s weight in pounds divided by the square of its diameter in inches. A higher figure means more mass behind each unit of frontal area, which generally helps a bullet keep its momentum and penetrate better.
In imperial units, multiply the bullet weight in grains by the velocity in feet per second squared, then divide by 450,240. The result is energy in foot-pounds. Multiply by 1.356 to convert to joules.
Not necessarily. Heavier bullets usually have higher sectional density and momentum but travel slower for a given load. The right choice depends on the purpose, rifle, barrel twist, bullet construction and legal requirements.
Energy depends on weight and the square of velocity, so it favours fast, light bullets. Momentum depends on weight multiplied by velocity, so it favours heavier bullets. Comparing both gives a fuller picture than either one alone.
No. This calculator only compares bullet properties and is not load data. Always follow published reloading manuals and the manufacturer’s guidance, and follow your local laws and safe handling practice.