VCFAPI

The hosted API for API MPMS Chapter 11.1-2004 volume correction.

Volume correction factors for crude oil, refined products, and lubricants — one HTTP call, 28 tables, zero install.

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28 tables · °F and °C · VCF to 5 decimals · 20 free credits · no card

A 0.01% volume error is $700 on one tank.

On a 100,000-barrel tank at $70 per barrel, a 0.01% volume correction error is $700 — once. Across a terminal, a month of transfers, a custody cycle, it compounds. Volume correction factors are the piece most often trusted to a spreadsheet, an old add-in, or a manual table lookup.

Measurement software should not be licensed per machine.

One API key serves your whole team. No installs, no per-seat licenses, no custom quotes.

Ship API 11.1 in an afternoon, not a quarter.

Implement volume correction once, correctly, then never touch the tables again. VCF API covers the tables you need in both unit systems:

Imperial

Table 5 — API gravity at 60°F

Table 6 — VCF (CTL) °F

Table 23 — relative density at 60°F

Table 24 — VCF (CTL) °F

Metric

Table 53 — density at 15°C

Table 54 — VCF (CTL) °C

Table 59 — relative density at 15°C

Table 60 — VCF (CTL) °C

28 table variants in total, including special application tables (6C, 24C, 54C, 60C), across all product groups: crude, refined products, lubricants.

# Table 6A, 86 °F, 35 °API — returns the VCF for custody transfer

POST /v1/vcf

{
  "table": "6A",
  "temp": 86,
  "density": 35
}

# 200 OK — one credit consumed:

{
  "request_id": "…",
  "table": "6A",
  "result": 0.98765,
  "credits_used": 1,
  "remaining_credits": 49,
  "metered_via": "credits",
  "remaining_quota": null
}

Units are table-dependent: tables 5/6 and 23/24 take °F, tables 53/54/59/60 take °C. 4xx responses cost nothing — only a 200 counts against your quota or credit balance.

The tables are the hard part.

VCF API implements the published API MPMS Chapter 11.1-2004 tables directly — no custom math, no approximations. Getting one table, one product group, or one rounding convention wrong produces silent errors: results look right and aren't.

28 table variants

Tables 5, 6, 23, 24 (imperial) and 53, 54, 59, 60 (metric), including special application tables.

Both unit systems

°F for imperial tables, °C for metric tables.

5 decimals

VCF output at 5 decimal places, per the standard's convention.

FAQ

What is a Volume Correction Factor (VCF)?

A Volume Correction Factor (VCF) is a multiplier that converts oil volume measured at an observed temperature to its equivalent volume at standard reference conditions (60°F / 15°C / 20°C), per ASTM D1250-04.

Which tables do you cover?

28 table variants: Tables 5, 6, 23, 24 (imperial) and 53, 54, 59, 60 (metric), across product groups A (crude), B (refined) and D (lube oil), plus special applications 6C, 24C, 54C, 60C (thermal expansion coefficient).

What precision does the VCF come back at?

Volume correction factors are returned to 5 decimal places, matching the API MPMS Chapter 11.1-2004 convention.

When am I charged?

Only a successful calculation (HTTP 200) counts against your quota, credit balance, or overage meter. Validation errors, auth failures, and rate-limit responses (4xx) are free.

What happens when I run out of credits or quota?

Calls draw from your subscription quota first (with rollover, capped at 1× your plan quota), then from your credit balance, then from paid overage when enabled. Overage is billed at $0.06 per call via your Polar subscription. If all three are exhausted, the API returns HTTP 402. You can enable overage or subscribe to a plan in the dashboard at any time.

How does VCFAPI pricing work?

VCFAPI offers monthly subscription plans with a call quota and rollover, plus paid overage when you exceed both your quota and credit balance. A successful call counts against your quota or credit balance; new accounts receive 20 free credits to start.

Which product types does VCFAPI support?

VCFAPI supports crude oil, refined petroleum products (diesel, gasoline, kerosene), and lubricating oils following the ASTM D1250-04 / API MPMS Chapter 11.1-2004 methodology.

Who is VCFAPI for?

Measurement engineers, terminal operators, trading companies, and software developers building custody transfer or inventory systems. VCFAPI replaces spreadsheet formulas, legacy add-ins, and per-machine measurement licenses with a single HTTP API.

Is there a free tier?

Yes — 20 free credits on signup, no card required. Enough to run the integration and validate your first products.

Do unused subscription quota roll over?

Yes — unused monthly quota carries over to the next month, capped at 1× your monthly quota, so an abandoned subscription can't accumulate an unbounded balance.

What is your refund policy?

Monthly subscription fees are non-refundable once the billing period has started. If you believe a charge was made in error, please contact us within 7 days and we will review it on a case-by-case basis.

How long are usage logs kept?

Per-request logs visible in the Logs dashboard are kept for 90 days. After that the individual entries are deleted and are no longer visible. Credit transactions — purchases, refunds, adjustments, and grants — are kept permanently and are always visible in the billing history.

Do I need to install anything?

No. VCF API is a hosted HTTP API. You send JSON, you receive JSON.

What about dedicated deployment?

Enterprise plans include a dedicated cloud / private deployment option. Contact us via the contact page.

Correct volume. Every call. Zero install.

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