Why SIP Trunk Pricing Is Confusing

Most SIP trunk providers advertise a "from $5 a month" price on their homepage and then bury the real cost in quote forms and long contracts. The true monthly bill is usually a mix of:

  • A per-channel or per-trunk fee (often $10–$25 per concurrent call path)
  • A per-DID monthly rental (separate from the trunk fee)
  • A setup fee (one-off, but sometimes $50–$200 per trunk)
  • Per-minute rates for outbound calls that vary by destination
  • Minimum spend or commitment clauses

This article compares the most common European providers using a consistent benchmark: one active trunk, five local DIDs, and 500 outbound minutes per month split across European destinations.

The Benchmark

To make the comparison fair, we assume a small European business with:

  • 1 SIP trunk with 4 concurrent calls
  • 5 local DID numbers (one each in NL, DE, FR, UK, BE)
  • 500 minutes per month of outbound calls to European mobile numbers
  • No setup fees or onboarding costs baked in

On this workload, providers that charge per channel can quickly cost $100+ per month, while pay-as-you-go providers like DIDfarm come in under $30.

What To Look For (Besides Price)

1. Per-Channel vs Unlimited Concurrent Calls

Traditional providers like voxbone/bandwidth and Gamma charge per concurrent call path. If your business spikes to 10 simultaneous calls during a campaign, you are paying for 10 channels permanently. DIDfarm lets you burst freely without pre-provisioned channels — you only pay for the DID and the minutes actually used.

2. Setup and Termination Fees

Watch for one-off activation fees or "number release" charges when you cancel. These are common with German and French providers. DIDfarm has no setup fees and no release fees — you can order and cancel as many numbers as you want without penalties.

3. Contract Length and Minimum Spend

Many providers require 12 or 24 month contracts, with auto-renewal. Small businesses should look for month-to-month billing. DIDfarm bills monthly from a prepaid wallet — see the wallet documentation for how top-ups work.

4. Porting Fees

If you already own a phone number, you want to port it in. Some providers charge $100+ per number. Look for providers with free porting (DIDfarm does this for most European countries, though regulatory steps apply).

5. SMS and Messaging

Not every SIP trunk provider supports SMS on DID numbers. If you need two-factor authentication or customer messaging, verify SMS is included before committing. DIDfarm supports SMS and WhatsApp through the same API on Messaging.

How DIDfarm Compares

DIDfarm is built for small and mid-size businesses that want predictable, transparent pricing without contracts:

  • No setup fees — create a trunk and order numbers for free
  • No per-channel fees — burst to as many concurrent calls as your PBX supports
  • From EUR 1.49/month per DID — see full pricing
  • Pay-per-minute outbound — rates vary by destination, billed per-second
  • No contracts — release numbers any time, no penalty
  • Works with any PBX — 3CX, FreePBX, Asterisk, Teams, Zoom Phone

Calculating Your Actual Monthly Cost

Use this formula to estimate your true monthly spend on any provider:

  1. Start with the per-trunk or per-channel fee × number of channels you need
  2. Add the DID rental × number of numbers
  3. Add the outbound minute spend = expected minutes × per-minute rate
  4. Add one-twelfth of any annual setup fees
  5. Multiply by 1.2 for the first year to account for ramp-up and hidden fees

Our pricing calculator does this automatically if you enter country, quantity, and usage.

Next Steps