SAF Blend & CO2 Savings Calculator
Model how a sustainable aviation fuel blend lowers a flight’s lifecycle carbon compared with running on conventional Jet A.
The saving is upstream, not at the tailpipe
Sustainable aviation fuel is the nearest-term lever the industry has for cutting flight emissions, precisely because it drops into today’s aircraft and airports without new engines. But its benefit is easy to overstate: a modest blend of a partly-cleaner fuel produces a modest overall cut. Multiplying the two percentages together keeps the expectation honest.
Use the Jet Fuel CO2 Emissions calculator to see the baseline you are cutting from, and the Fuel Cost per Flight calculator to weigh the savings against SAF’s higher price.
Frequently Asked Questions
How is the CO2 saving calculated?
The saving comes only from the SAF fraction, and only from its upstream lifecycle. The tool takes your total fuel, works out the SAF portion from the blend percentage, and reduces that portion's lifecycle CO2e by the reduction percentage you enter. The net result is simple: total reduction equals blend percentage times lifecycle reduction. A 40% blend of a fuel that is 75% cleaner cuts total lifecycle CO2e by 30%.
Doesn't SAF still produce CO2 when it burns?
Yes. SAF is a drop-in hydrocarbon, so burning it releases tailpipe CO2 at close to the same rate as Jet A. The climate benefit is that the carbon was largely taken up recently — from plants, waste, or captured CO2 — rather than dug up as fossil carbon, so its lifecycle emissions are much lower. That is why this tool reports a lifecycle (well-to-wake) saving, not a tailpipe one.
What blend percentage can airlines actually use?
Under current fuel specifications, most certified SAF pathways are approved for blends up to 50% with conventional jet fuel, and in practice airlines often use far less. Neat (100%) SAF is being tested and is a goal for the future, but is not yet standard. The tool lets you model any blend so you can compare scenarios.
What lifecycle reduction should I enter?
Certified SAF pathways commonly report lifecycle CO2e reductions of roughly 70–80% versus fossil Jet A, though it varies widely by feedstock and production route — some are lower, and a few advanced pathways claim more. If you have a specific fuel's certified figure, use it; otherwise 75% is a reasonable middle estimate.
Educational estimate only. Real lifecycle values are certified per fuel batch and pathway; this tool models the arithmetic, not a specific fuel’s accredited figure.