Mathematical Integrity
Calculation Methodology & Evidence Standards
Every number shown on SMB Cost Diagnostic is calculated with integer cents arithmetic from reviewed public documentation. We do not use probabilistic estimates or opaque AI scores.
1. The 12-Month Total Cost Formula
For any evaluated pricing plan, the monthly recurring cost is computed as:
The first-year (12-month) commitment cost is then:
All intermediate values are represented as non-negative integer cents (USD minor currency units). Floating point rounding errors are strictly avoided.
2. Call Rounding & Unit Differences
Providers bill either by the call or by the minute:
- Per-Call Billing: Usage is simply the total number of calls received.
- Per-Minute Billing: Standard industry terms dictate that each call is rounded up to the next full minute. A 65-second call consumes 2 full minutes. In our calculator, estimated minutes equal:
usage_minutes = monthly_calls * ceil(avg_seconds / 60)
3. The “Incomplete” Rule (Zero vs. Unknown)
A foundational rule of our site is: Unknown is null, not zero. If a provider does not state an activation or setup fee on their public pricing table, we do not assume setup is $0. We mark the annual calculation as Incomplete and exclude it from lowest-cost rankings.
4. Fact Verification Lifecycle
Facts undergo review against primary documentation. Facts are classified into:
- Verified: Directly verified by human review against primary source.
- Unknown: Not published or requires individual sales quotes.
- Stale: Surpassed 30 days without re-verification; queued for review.
- Conflicting: Divergent claims between marketing and legal terms.