Why FiveNinths
ExactnessFiveNinths implements conversions precisely using fixed-point decimal arithmetic. This ensures that every calculation is mathematically accurate. There are no floating-ponit errors, only exact, reproducible results.
AuditabilityEvery request and response is tracked with an API key and UUID. This means every conversion is fully auditable, making it easy to verify calculations, reproduce results, and maintain compliance with internal or regulatory requirements. You always know which formula was used and when.
DeterminismIdentical inputs always produce identical outputs. No random rounding, no context-dependent behavior—just consistent, predictable conversions. This deterministic behavior makes FiveNinths reliable for automated systems, batch processing, and mission-critical applications.
Standards-compliantFiveNinths adheres strictly to international temperature definitions, including SI standards. All conversions are performed according to recognized formulas, ensuring that your results are universally correct and compatible with scientific, engineering, and industrial workflows.
How It Works
Request
POST /v1/convert
{
"from": "celsius",
"input": 100,
"to": "fahrenheit",
"rounding": {
"dp": 4
}
}Response
{
"output": "212.00",
"request": {
"from": "celsius",
"input": "100",
"to": "fahrenheit",
"rounding": {
"dp": 4,
"strategy": null
}
},
"rounding": {
"dp": 4,
"strategy": midpoint_away_from_zero
},
"unit": "fahrenheit",
"uuid": "51d4aec4-1058-490f-89d8-fc2d96317a0f"
}Pricing
Individual
Free
Try FiveNinths before committing.
- Up to 1,000 conversions per month
- Standard rounding only
- Ideal for testing integrations or evaluating the API
Professional
$99/month
For teams and small businesses that rely on precise, auditable conversions.
- Up to 100,000 conversions per month
- Full rounding options with configurable strategies
- UUID-based audit logs for every request
- Priority email support
Enterprise
Contact Sales
For large organizations with long-term audit requirements and mission-critical applications.
- Custom volume and usage limits
- Advanced auditing and compliance options
- Dedicated account and technical support