The Prompt Token Optimizer converts a planned reduction in input prompt length into token and dollar savings at daily, monthly, and yearly volume. It is built for teams that can measure an existing prompt, estimate a realistic reduction, and want a direct cost figure before rewriting instructions or examples.
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The calculation counts input tokens only. Output tokens, cache pricing, and quality changes are not fields in this calculator, so treat the result as the avoided input-token charge implied by the entered rate.
How to use it
Enter Current prompt tokens per call. The default is 1,500 tokens. This should include every repeated system instruction, example, retrieved block, and static policy that is billed as input.
Enter Achievable reduction as a percentage. The default is 30%, and the formula clamps values below 0% to 0% and values above 100% to 100%.
Check a reduced prompt against a small real task set before counting its projected savings as available.
Set API calls per day and Input price per 1M tokens. Defaults are 5,000 calls and $3 per million tokens. The calculator uses 30 days for monthly savings and 365 days for yearly savings.
Read tokens saved per call first, then compare the three money tiles against the engineering effort required to reduce the prompt.
Fields explained
Current prompt tokens (per call) – billed input length before editing. Default: 1,500 tokens; step: 1.
Achievable reduction (%) – fraction of the prompt removed. Default: 30%; step: 1 percentage point; clamped from 0% to 100%.
API calls per day – daily request count. Default: 5,000; step: 1.
Input price per 1M tokens – dollar rate used for avoided input tokens. Default: $3; step: $0.01.
Reading the results
| Result | Meaning | Action |
|---|---|---|
| Tokens saved / call | Prompt tokens times reduction | Inspect what is being removed. |
| Saved / day | Daily avoided input charge | Compare with daily traffic logs. |
| Saved / month | Daily saving times 30 | Use for monthly budget planning. |
| Saved / year | Daily saving times 365 | Use for an annual estimate. |
The first tile also prints the tokens left after reduction. It rounds both token values to whole numbers before display.
Removing 30% of a 1,500-token prompt saves 450 tokens per call.
Warning: the result assumes every call receives the same reduction and pays the same input-token rate.
Monthly and yearly outputs use different day counts, so yearly is not monthly multiplied by 12. The source explicitly uses 365 daily savings for the annual tile.
The formula
The code uses savedPerCall = promptTokens × reduction, newTokens = promptTokens - savedPerCall, dailyTokensSaved = savedPerCall × callsDay, and dailyCostSaved = dailyTokensSaved / 1,000,000 × inputPrice. Monthly saving is daily saving times 30; yearly saving is daily saving times 365.
| Default | Value |
|---|---|
| Prompt | 1,500 tokens |
| Reduction | 30% |
| Calls | 5,000/day |
| Input price | $3/1M |
The defaults produce 450 saved tokens per call and 1,050 left. Daily saved tokens are 2,250,000; daily savings are $6.75; monthly savings are $202.50; yearly savings are $2,463.75.
Info: the source suggests removing redundant instructions, compressing few-shot examples, and moving static context to prompt caching.
Those are possible ways to achieve an entered reduction, not automatic features of the formula.
Worked examples
Small internal tool. A 600-token prompt, 20% reduction, 100 daily calls, and $3/1M saves 120 tokens per call, 12,000 daily tokens, and $0.04 per day. Retain a baseline quality test.
Default workload. The built-in values save $202.50 per 30-day month. Compare that number with prompt-review time.
Growing service. At 2,000 tokens, 25%, 20,000 calls/day, and $4/1M, savings are 500 tokens per call, 10M tokens/day, $40/day, $1,200/month, and $14,600/year. Test the shorter prompt on failure cases.
Scale case. At 4,000 tokens, 40%, 100,000 calls/day, and $5/1M, daily savings are $800 and yearly savings are $292,000. The formula leaves 2,400 prompt tokens per call. Review repeated context first.
Common mistakes
Entering a character count as tokens distorts every output. Use model-tokenizer counts.
Using an output-token price understates or overstates this input-only calculation. Enter the input rate.
Assuming a 100% reduction means a usable prompt hides a quality risk. The code allows it mathematically, while a live task may not.
Danger: an invalid numeric input becomes zero in the source, which can show zero savings instead of an error.
Replace blank or invalid values with measured inputs before making a budget decision.
FAQ
Does this price output tokens?
No. It uses one input price per million tokens.
Output length does not appear in the formula.
Why is yearly different from 12 months?
The code multiplies daily savings by 365.
Monthly savings use 30 days, so 12 monthly outputs represent 360 days.
Can reduction exceed 100%?
The calculator clamps it at 100%.
It cannot display negative remaining tokens.
Does caching reduce the same tokens?
The tool calculates only an entered token reduction.
Caching has its own provider pricing and behavior.
What should I test first?
Test the shorter prompt on representative requests.
Compare success rates before applying a 30% or larger reduction to traffic.
Disclaimer
This is an educational estimate for planning. Results depend on the model, provider, hardware, configuration, and current pricing, all of which change.
The live calculator on the page is the source of truth for its exact fields. Verify against current prices and a small real test before scaling spend.
