Does a VPN slow down internet speed?
Also asked as: How much does a VPN slow down your internet? · Why is my VPN slow?
Direct answer
A little, always; a lot, only when something is wrong. Encryption and the detour through a server typically cost 10 to 30 percent of throughput and add the round-trip time to the server — a few milliseconds to a nearby one, over a hundred to another continent. Picking a close server on a modern protocol like WireGuard keeps the loss small.
Where the speed goes
Distance. Your traffic goes to the server and back before it goes anywhere else. A server in your own country adds 5 to 20 ms; one across an ocean adds 70 to 250 ms, and that is physics, not tuning.
Encryption. Every packet is encrypted and decrypted, which costs CPU on both ends. WireGuard with ChaCha20-Poly1305 is fast enough that on a phone or laptop this is rarely the bottleneck; older protocols and slow routers are where it bites.
The server's own link. A busy or under-provisioned server caps you at whatever it has left. This is the part that varies most between providers.
How to lose as little as possible
Pick the nearest server unless you need a specific country. Use WireGuard rather than OpenVPN where you have the choice. Test on Wi-Fi and on a cable, because a weak Wi-Fi link will be blamed on the VPN. And measure before and after with the same tool on the same connection, because a speed test run once tells you nothing.
On VPNmine
Every VPNmine app uses WireGuard, and the apps can pick the closest of the 68 countries automatically. The speed test on this site measures your connection both ways against servers VPNmine operates, so you can compare with the tunnel up and down on the same link.
Related questions
- Which VPN location should I choose?Pick the closest server for speed and a specific country only when you need to appear there. Why distance dominates latency, and how to let the app choose.
- What is WireGuard?WireGuard is a modern VPN protocol: small codebase, fixed modern ciphers, one-round-trip handshake, fast reconnects. Why it replaced OpenVPN in most apps.
- WireGuard vs OpenVPN: which is better?WireGuard is faster, smaller and reconnects better; OpenVPN is older, bigger and can run over TCP 443. Which to pick, and why VPNmine's apps use WireGuard.
- How does a VPN work?What happens when you press connect: key exchange, encrypted tunnel, a server that forwards your traffic, and why sites see its address, not yours.