How many numbers to prospect effectively?
The exact formula to never burn your lines
THE GOLDEN RULE
The 1.3 coefficient covers the safety margin for rotation and contingencies.
The detailed formula
1. Count your total daily calls
2. Divide by your sector threshold
3. Multiply by 1.3 (safety margin)
= Recommended number of lines
THRESHOLDS BY SECTOR
Instant calculator
guide_numeros_prospecter.calc_backup_note
| Calls / day | Recommended numbers |
|---|---|
| 20-30 calls | 2 numbers |
| 30-50 calls | 2-3 numbers |
| 50-80 calls | 3-4 numbers |
| 80-120 calls | 4-5 numbers |
| 120-200 calls | 5-7 numbers |
| 200-300 calls | 7-10 numbers |
| 300-500 calls | 12-15 numbers |
| 500+ calls | 15-20+ numbers |
| Sector | Recommended numbers |
|---|---|
| B2B SaaS / Tech | 4 numbers |
| Recruitment | 4 numbers |
| Insurance | 5 numbers |
| Telecom | 5 numbers |
| Real Estate | 6 numbers |
| Credit / Buyback | 6 numbers |
| Energy / Renewables | 8-10 numbers |
| CPF Training | 8-10 numbers |
| Real estate lead gen | 12+ numbers |
Why multiply numbers
Dilute call volume
Fewer calls per number = fewer reports = better reputation.
Enable rotation
Alternating numbers lets each one "rest" and avoid overheating.
Absorb losses
If one number burns, the others take over without service interruption.
Test prefixes
Some prefixes get better pickup rates by region. More numbers = more testing possible.
Rotation strategies
Hourly rotation
Change number every 2 hours. Ideal for intensive campaigns of 50+ calls/day.
Daily rotation
A different number each day. Simple to manage, effective for moderate volumes.
Per-rep rotation
Each rep has 3 to 5 numbers they alternate. Keeps a per-person history.
Shared pool
Numbers are automatically distributed from a common pool. Best protection for high volumes.
The backup stock
Always keep 30% more numbers than your calculated need.
These dormant numbers are your safety net.
The 5 fatal mistakes
"One number for the whole team"
That number will burn in a few days. Your pickup rate will collapse.
"No rotation"
Even with multiple numbers, without rotation, you concentrate calls on one.
"Ignoring reports"
A reported number that keeps calling worsens its score exponentially.
"Reusing a burned number too soon"
Putting a number back in service before its reputation recovers is counterproductive.
"Not monitoring scores"
Without monitoring, you discover the problem when nobody picks up anymore.
Cost / benefit analysis
| Strategy | Cost / Risk |
|---|---|
| Rotation with monitoring | €50 to €200/month |
| No rotation (blocked numbers) | Loss of 30 to 60% of prospecting revenue |
| Monitoring ROI | ×5 to ×20 the cost |
Frequently asked questions
How many numbers for 50 calls per day?
Should I use different prefixes?
Can I prospect with just one number?
How many backup numbers to keep in stock?
How do I know if my numbers are sufficient?
Calculate your number needs
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