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We read every message. We usually reply within a few days, but we cannot promise a set response time.

Helpful details to include

Calculator questions: your tank size, readings and the units you used.
Corrections: the page address, what you think is wrong, and a source if you have one.
Tool suggestions: what you were trying to work out and what the tool should ask for.

We cannot give individual professional advice. Please do not send passwords, payment details or other sensitive personal information.