Enter your carbon fiber or steel tank's size and pressure range, along with your rifle or pistol's reservoir size and fill pressure, to estimate how many fills you'll get from one tank. Switch to Compare to check fills across a few guns against the same tank.
This calculator uses Boyle's Law, at a constant temperature, the amount of gas in a given space is proportional to pressure multiplied by volume. Your fill tank and your gun's onboard reservoir are both fixed volumes, so the amount of air your tank can hand off to your gun, fill after fill, can be worked out directly from the pressure drop and the two volumes involved.
Your tank's cutoff pressure isn't zero, it's the point where the tank no longer holds enough pressure to fully top off your gun. Once your tank's pressure drops close to your gun's fill pressure, fills take longer and stop fully topping off the reservoir. A common practice is setting cutoff a few hundred PSI above your gun's fill pressure, adjust the number here to match your own setup.
Switch the calculator above to Compare to see how many fills the same tank gives you across a few different guns, useful if you own more than one PCP airgun and want to know which one goes through your tank fastest. Enter your tank's specs once, then add each gun's reservoir size and fill pressure below it.
A rifle with a small reservoir filled to a lower pressure will drain a tank far slower than one with a large reservoir filled to a high pressure, even if both claim similar shot counts per fill. Efficiency (how much energy a gun gets out of a given volume of air) varies by gun and by tune, so this calculator estimates fills based on raw air volume moved, not how efficiently that air is used downrange.
This calculator is free to embed anywhere, including WordPress, no plugin required. Paste the code below into a Custom HTML block (or anywhere in your page's HTML):
<iframe id="airgunguide-tankfill-embed" src="https://airgunguide.com/embed/airgun-tank-fill-calculator.html" width="100%" height="950" style="border:1px solid #c9c0a5;max-width:420px;" title="Airgun Tank Fill Calculator"></iframe>
<script>
(function(){
window.addEventListener('message', function(e){
if(!e.data || e.data.type !== 'airgunguide-embed-resize' || e.data.embedId !== 'airgunguide-tankfill'){ return; }
var f = document.getElementById('airgunguide-tankfill-embed');
if(f){ f.style.height = e.data.height + 'px'; }
});
})();
</script>The small script after the iframe lets the calculator resize itself automatically as you switch modes or add guns, so it never shows an internal scrollbar. In WordPress specifically: add a Custom HTML block to your page, paste the code above into it, and publish. That's it, no account, no API key, and no plugin needed.