Free SIP and VoIP tools
Small tools that answer one question each, free and without an account. They run in your browser, so numbers you type stay on your device.
Tool pages
Open one, get the answer, copy it out.
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International number formatter
Paste one phone number or 200. Get each in E.164 and international format, whether it is valid, its type, and how to dial it from your country.
- E.164 conversion
- Validity and number type
- Copy as CSV
VoIP bandwidth calculator
Kbit/s per call and for all your calls at once, by codec, with VPN and encryption counted, plus how many calls fit on your upload.
- G.711, G.722, G.729, Opus
- VPN and SRTP overhead
- Calls per connection
Tools inside our guides
Some tools sit next to the explanation they belong with.
Each link opens the guide at the tool. All guides: SIP and international calling guides.
- $Rate checkType any international number and see its country, number type and rate per minute.In: International call rates
- =Call cost calculatorYour provider's rate, rounding and connection fee in; the real cost per call and per minute out.In: International call costs
- FIXSIP fault finderStart from what you see on a failing call and narrow it down to the likely cause and fix.In: SIP troubleshooting
- 4xxSIP code lookupType a code, or paste the line from your log, and see what it means and who sent it.In: SIP response codes
- ALGSIP ALG by routerPick your router brand to see where SIP ALG is switched off.In: SIP ALG
- AAttestation checkerChoose how your calls are made to see the STIR/SHAKEN grade they usually get, and why.In: STIR/SHAKEN
- 1:1Channels and uploadHow many people talk at once at your busiest moment gives the channels and upload you need.In: SIP trunk guide
- DIDWhich virtual numberOne question about where calls should ring picks the kind of number you need.In: Virtual phone numbers