CSV or manual entry
Import Garmin ShotView, LabRadar, or a generic velocity CSV, or enter individual readings.
Free chronograph calculator
Calculate chronograph SD, ES, and average velocity.
Paste your shot velocities, add them one at a time, or import a CSV. Review the string on a graph and temporarily exclude a questionable reading without losing it.
No account required. Your velocity data stays in this browser session unless you save it inside ArsenalHQ.
Enter your velocity string
Paste values separated by lines, spaces, or commas, or import a chronograph CSV.
Paste, import, or add velocities to begin.
Average
N/A
FPS
Standard deviation
N/A
FPS
Extreme spread
N/A
FPS
Included shots
0
SHOTS
Minimum
N/A
FPS
Maximum
N/A
FPS
Velocity by shot
Included shots only
Include at least two shots to graph the string.
Review shots
Exclude a bad reading without deleting it. Select it again to restore it.
Keep the string in context
Velocity data is more useful when it stays with the range day.
Inside ArsenalHQ, save chronograph results with the firearm, ammunition, recipe, target, weather, and notes that produced them. Compare performance later without rebuilding the story from separate files.
Create a free accountFree during launch. No credit card required.
Connected ammunition
Attach the string to factory ammunition or the handload recipe and batch that produced it.
Firearm history
Save results with the firearm while its lifetime round count and barrel-life progress stay current.
Target and MOA
Keep velocity statistics beside the marked target photo and calculated group size.
Automatic weather
Pull conditions from the range location and session time, or record them manually.
Inventory updates
Logging the rounds fired deducts the correct ammunition from inventory automatically.
Read the string
What the chronograph statistics tell you
Average velocity
The arithmetic mean of every included shot in the string.
Standard deviation
A measure of how far the included velocities tend to vary from the average.
Extreme spread
The fastest included shot minus the slowest included shot.
Shot count
The sample size shown alongside the result so short and long strings are not mistaken for equal evidence.
Consistent calculation
Sample standard deviation
ArsenalHQ calculates sample standard deviation using n minus one. That keeps this public calculator consistent with the velocity statistics saved inside the app. Excluded readings are removed from every displayed result until you include them again.
SD = √(Σ(x − x̄)² ÷ (n − 1))
Common questions
Chronograph calculator FAQ
What do SD and ES mean on a chronograph?
Standard deviation describes how tightly the velocities cluster around the average. Extreme spread is the difference between the fastest and slowest included shots.
Does this calculator use sample or population standard deviation?
It uses sample standard deviation, dividing by n minus one. This is the same calculation ArsenalHQ uses for saved chronograph strings in range days.
How many shots should be in a chronograph string?
The useful sample size depends on what you are testing. More shots generally provide a more stable picture of variation than a very short string. Keep the shot count visible when comparing results.
Can I exclude an incorrect chronograph reading?
Yes. Select any shot in the review list to exclude it from the calculation and graph. The value stays visible and can be restored at any time.
What CSV files can I import?
The calculator recognizes Garmin ShotView, LabRadar, and generic CSV files with a velocity, speed, or FPS column. Export formats can vary, so pasted or manual entry remains available.