Sales email personalisation: what it costs and which AI to use
Write a tailored opening line or a whole outreach email for each lead from a short profile. Sales and growth teams running outbound at volume.
The short answer
At 5,000 emails a month, we estimate $0.595 on DeepSeek V4 Flash 0423 (the cheapest model that cleared our quality bar), $7.21 on Kimi K2.7 Code, and $59.60 on GPT-5.5. The flagship costs 8.3x the middle pick. Judged on rewriting and extraction tasks: tone, no invented facts about the lead.
Simulate your sales email personalisation
Pick a job, set how much of it you do, and see what every model would cost. Defaults are typical, not yours. Change them.
Prompt, history, documents
What the model writes
Advanced: caching, reasoning, retries, discounts
Share that can use cached-input prices where a model offers them
1 = none. 2 = hidden thinking doubles billed output
Extra calls on top of the base count
Batch jobs or committed spend. Check your provider; we assume none by default
Lowest benchmark score a model can have and still be picked. Higher is stricter.
Limit to certain providers
Untick any provider you cannot use, for data-residency, contract or policy reasons. Picks are recalculated.
5,000 emails a month, three ways to pay
Every model here cleared a score of 9.0 out of 10 on our rewrite, extract json benchmark tasks, ran without errors and fits a 8K-token window. 25 of 386 priced models qualify.
Cheapest model that clears the bar.
DeepSeek V4 Flash 0423
- Per email
- $0.0001
- Benchmark
- 9.50 / 10 · 6 prompts
- Context
- 1.05M tokens
Priced near the middle of the models that clear the bar; best score there.
Kimi K2.7 Code
- Per email
- $0.0014
- Benchmark
- 9.50 / 10 · 6 prompts
- Context
- 262K tokens
What many people reach for first.
GPT-5.5
- Per email
- $0.012
- Benchmark
- 9.50 / 10 · 6 prompts
- Context
- 1.05M tokens
Choosing GPT-5.5 over Kimi K2.7 Code costs $52.39 more a month, $629 a year (8.3x the price).
Both scored 9.50 out of 10 on this kind of work. The extra money buys safety margin our benchmark cannot measure: it is 24 short prompts, and most passing models score near the top. If a wrong answer is costly for you, that margin can be worth it. Test on your own data before you decide.
If it grows
Pay-per-use cost scales in a straight line. Monthly cost at 1x, 3x, 10x and 100x today's volume.
| Model | 1x · 5,000 | 3x · 15K | 10x · 50K | 100x · 500K |
|---|---|---|---|---|
| DeepSeek V4 Flash 0423 | $0.595 | $1.79 | $5.95 | $59.51 |
| Kimi K2.7 Code | $7.21 | $21.63 | $72.10 | $721 |
| GPT-5.5 | $59.60 | $179 | $596 | $5,960 |
What a budget buys
- DeepSeek V4 Flash 0423840Kemails a month, about 28K a day
- Kimi K2.7 Code69Kemails a month, about 2,311 a day
- GPT-5.58,389emails a month, about 279 a day
Every model, priced for your workload
41 models, 3 hidden because their window is smaller than 8K tokens.
| Model | A month | Per email | Benchmark | Context |
|---|---|---|---|---|
| DeepSeek V4 Flash 0423 DeepSeekBudget pick | $0.595 | $0.0001 | 9.50 (6) | 1.05M |
| Ministral 3 8B 2512 Mistral AI | $0.738 | $0.0001 | 9.50 (6) | 262K |
| Llama 4 Scout Meta | $0.871 | $0.0002 | 9.33 (6) | 1.31M |
| DeepSeek V4.1 Flash DeepSeekbelow the bar | $0.888 | $0.0002 | 8.17 (6) | 1.05M |
| Qwen3.8 Flash Alibababelow the bar | $1.19 | $0.0002 | 8.50 (6) | 1M |
| GLM 5.3 Flash Z Ai | $1.26 | $0.0003 | 9.50 (6) | 1.05M |
| Mistral Small 4 Mistral AIa benchmark run failed | $1.37 | $0.0003 | 9.60 (5) | 262K |
| MiniMax M2.5 Minimax | $2.29 | $0.0005 | 9.50 (6) | 205K |
| GLM 5.3 Z Aibelow the bar | $2.34 | $0.0005 | 8.50 (6) | 1.05M |
| GPT-5.4 Nano OpenAI | $2.45 | $0.0005 | 9.50 (6) | 400K |
| Muse Glimmer 30B Meta | $2.76 | $0.0006 | 9.50 (6) | 131K |
| MiniMax M2.7 Minimaxbelow the bar | $2.80 | $0.0006 | 8.00 (6) | 205K |
Benchmark = mean judge score out of 10 on the rewrite, extract json prompts of the Model Playground, with the number of prompts in brackets. Models marked n/a have no benchmark run, so we do not guess their quality. How the benchmark works.
What we assumed
- Five thousand emails a month.
- Each call sends a lead profile and template, about 1,100 tokens.
- Each email is about 180 words, roughly 280 tokens.
- 40% of input (template and instructions) repeats.
These are typical numbers, not measurements of your business. Edit them in the simulator above.
What drives the cost
Volume again, with short outputs. The model sees a profile and a template and writes a few sentences.
Watch out for
- The model call is the cheap part. Data enrichment and sending tools usually cost far more.
- Invented details about a lead hurt more than a generic opening. Test for it before you scale.
Questions people ask
How much will sales email personalisation cost per month?
At 5,000 emails a month, we estimate $0.595 a month on DeepSeek V4 Flash 0423, the cheapest model that clears our quality bar for this job. Kimi K2.7 Code costs $7.21 and GPT-5.5 costs $59.60. These are estimates from the assumptions listed on this page, not a quote. Change the numbers to match your own volume.
What is the cheapest AI model for sales email personalisation?
On current OpenRouter prices, DeepSeek V4 Flash 0423 from DeepSeek is the cheapest model that cleared our bar of 9.0 out of 10, scoring 9.5/10 on 6 benchmark prompts for this kind of work. The benchmark is small, so treat it as a shortlist and test on your own data before switching.
Is it worth paying for a flagship model for sales email personalisation?
On our benchmark, GPT-5.5 scored 9.5/10 on this kind of work, and a model priced near the middle of the models that cleared the bar, Kimi K2.7 Code, scored 9.5/10, while the flagship costs 8.3x as much. A flagship buys safety margin the benchmark cannot measure. If a wrong answer is expensive for you, that can be worth paying for. If not, you are probably overpaying.
What happens to the cost if sales email personalisation grows ten times?
Pay-per-use pricing scales in a straight line, so ten times the emails is ten times the bill. Use the growth table on this page to see 3x, 10x and 100x for the same three models.
What makes sales email personalisation expensive?
Volume again, with short outputs. The model sees a profile and a template and writes a few sentences.
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