High-power　inductors　are　fundamental　components　in　high-power　DC–DC　converters,　with　their　performance　being　a　crucial　metric　of　converter　efficiency.　This　paper　presents　an　in-depth　analysis　of　a　novel　calculation　method　for　the　air　gap　length　in　such　inductors.　Taking　into　account　the　effects　of　air　gap　diffusion　and　the　winding　magnetic　field,　an　expression　for　the　air　gap　diffusion　radius　is　derived,　focusing　on　a　distributed　air　gap　structure.　Furthermore,　models　for　calculating　the　air　gap　and　winding　reluctance　are　developed,　grounded　in　electromagnetic　field　theory.　An　equivalent　magnetic　circuit　model,　formulated　based　on　Kirchhoff＇s　second　law,　facilitates　the　proposed　method　for　air　gap　length　calculation.　This　study　also　involves　the　development　of　3D　models　for　both　discrete　and　decoupled　integrated　inductors.　The　comparison　between　simulation　outcomes　and　calculated　air　gap　lengths　indicates　a　maximum　error　of　less　than　8%,　with　the　minimum　error　being　as　low　as　− 0.79%.　Compared　with　traditional　methods,　the　calculation　method　proposed　in　this　paper　has　significant　advantages.　Additionally,　the　discrepancy　between　calculated　values　and　experimental　measurements　is　found　to　be　1.11%.　These　results　validate　the　accuracy　and　applicability　of　the　theoretical　analysis　and　calculation　method,　underscoring　their　significance　in　the　design　and　optimization　of　high-power　DC–DC　converters.　©　The　Author(s)　2024.