Tens of thousands of Britons seeking to secure residency rights in EU countries in the event of a no-deal Brexit face fees of up to €210 (£183), tight application deadlines and minimum salary thresholds, a Guardian investigation can reveal.

The challenges for British nationals will vary across the 27 EU member states if a withdrawal agreement is not ratified. The European commission has suggested member states should take a “generous” approach, but apart from Ireland none of the EU member states are said by citizens groups to be offering terms on a par with the approach taken by the British government.

In the event of a no-deal exit, the estimated 3.6 million EU citizens who reside in the UK would have until the end of 2020 to register for settled status through a free online application in which they need to prove only their identity and that they live in the UK, and declare any criminal convictions.

Despite the repeated calls by the European parliament for the UK to improve its offer, many of the estimated 1.2 million British nationals living in the other 27 EU member states would be in significantly worse situations.

The 8,500 British citizens living in Austria face paying €210 for a residence permit or €195 for each child up to the age of six. France would charge €119. Some member states, including Germany, are yet to decide on the size of the fee.

Retired or otherwise non-economically active people who have lived in France for less than five years would have to apply each year for a visitor card costing €269, leaving those who are new to the country with a potential cost of more than €1,000. Self-employed Britons would need to show they have sufficient resources for their family, with a couple with two children required to provide evidence of an income of around €1,175 a month.

Denmark is yet to make a permanent offer for those seeking to stay beyond a “temporary transitional period” up to the end of 2019.

Two thousand Britons living in Poland who apply for long-term residency permits would have to prove they have not spent more than 10 months outside Poland in the last five years.

Grace periods for late applications range from three months after Brexit day in Germany – although that initial proposal is set to be extended to nine months when finally legislated – to three years for those living in Hungary.

Jane Golding, the chair of the lobby group British in Europe, said her members were now pushing for an EU-wide solution to be ringfenced in the event of Britain’s membership of the bloc being extended beyond 31 October.

“If there had been a ringfenced solution, in a no-deal scenario you would have an EU-wide solution. But what we are facing now is 27 different solutions,” she said. “In effect it is a European postcode lottery, and rather than our EU rights being safeguarded at an EU level, our rights are being outsourced to the 27 countries.”

Kalba Meadows, a psychotherapist who lives and works in France, said the biggest problem facing Britons in her adopted country was its six-month grace period after Brexit day for fresh applications to be made.

She said: “It’s one of the shortest in the EU27, which is surprising when you take into account that France is the only EU27 state that doesn’t require registration of EU citizens, so it’s a case of starting from scratch, unlike, say, Germany or Spain where everyone should already be registered. It’s hard to see, frankly, how 150,000 to 200,000 people are going to be able to register within such a short timescale, even in a perfect world.”

Meadows added: “We know that there are thousands of British residents out there who haven’t yet been reached, either by us or by the embassy’s publicity campaigns, so there’s a huge amount of work to be done and it needs to be done fast. Then there’s the issue of those who are especially vulnerable – those who are ill, very elderly, live alone, have no internet or no transport, those in care homes, those under tutelle [power of attorney] and so on.”

Boris Johnson has said the UK will leave the EU on 31 October, “no ifs or buts”, and it looks increasingly unlikely that a deal will be secured with Brussels at a summit this Thursday.

A UK government spokesperson said: “The government has given an unequivocal guarantee to EU citizens living and working in the UK that they can have absolute certainty of the right to live and remain in the UK after Brexit. We continue to urge all member states to reciprocate fully for UK nationals the guarantee that we have made to EU citizens.”