One way to calculate an estimate turnover when turnover is not listed is by using the Trade Debtor figure. Most "trade debtors" pay (on average) every 50-70 days (industry dependent).
So, for an estimation of turnover for a company that does not file full accounts you could look at the below calculation:Trade Debtors ÷ 50 (average sales per day) × 365
E.g. a company is reporting £500,000 in trade debtors:500,000 ÷ 50 (average sales per day) × 365 = 3,650,00.00
Estimated Turnover = £3,650,000.00