Exodus and Atomic are both desktop wallets for a variety of crypto coins. They both do no fiat exchanges, but they do dozens of conversions between crypto types. Exodus appears a lot more expensive even through both claim “no fees”. In fact, they both charge price spreads on the crypto prices, which sort of hides the costs unless you do some fancy math.
To do a cost comparison, I considered trading between ETH and BTC. The idea is to do a trade one way, then the other way and see what fraction of money I have left. If the spread was zero, I would have the same amount. If I’m left with 0.90 of the original amount, then the 1-way spread cost was about 5%.
Consider if the spread was 2% each direction. Assume the spot price is $4444 for ETH and $60,000 for BTC. 1 ETH * 0.98 => 0.072585 BTC. Now sell it back. 0.072585 BTC * 0.98 => 0.9604 ETH. And the square root of 0.9604 is… 0.98 .. the original 2% fee.
To do the calculation fast for any pair, just take the two conversion amounts multiplied by each other to get the 2-way cost, then take the square root to see the average both ways.
Using real numbers from Atomic, 1 BTC => 12.595351 ETH, and 1 ETH => 0.0757669 BTC. Multiplied together gives 0.9543, square root gives 0.9769 or 2.3% cost for a 1-way conversion. Using the same numbers from Exodus, 1 BTC => 11.998774 ETH, and 1 ETH => 0.07429081 BTC. Multiplied and square rooted gives 0.9441 or 5.6% 1-way cost conversion. When doing a comparison, grab the numbers quickly. Connected to the internet, both programs update the prices about every 30 seconds.
Atomic offers a network fee of $18.27 to sell ETH and Exodus seems to always come in a bit lower, maybe $16.55. The difference of $1.72 is eaten up in the consistently larger Exodus price spread. 5.6% compared to 2.3% is 3.3%, and 1.72 is 3.3% $5.21, so any trade more than $5.21 would make Atomic cheaper.