diff --git a/basicswap/basicswap.py b/basicswap/basicswap.py
index 0cec36b..e65c095 100644
--- a/basicswap/basicswap.py
+++ b/basicswap/basicswap.py
@@ -14,6 +14,7 @@ import base64
 import random
 import shutil
 import struct
+import urllib.request
 import hashlib
 import secrets
 import datetime as dt
@@ -1036,6 +1037,9 @@ class BasicSwap(BaseApp):
             msg_buf.amount_negotiable = extra_options.get('amount_negotiable', False)
             msg_buf.rate_negotiable = extra_options.get('rate_negotiable', False)
 
+            if msg_buf.amount_negotiable or msg_buf.rate_negotiable:
+                ensure(auto_accept_bids is False, 'Auto-accept unavailable when amount or rate are variable')
+
             if 'from_fee_override' in extra_options:
                 msg_buf.fee_rate_from = make_int(extra_options['from_fee_override'], self.ci(coin_from).exp())
             else:
@@ -5519,3 +5523,26 @@ class BasicSwap(BaseApp):
         if not self._network:
             return {'Error': 'Not Initialised'}
         return self._network.get_info()
+
+    def lookupRates(self, coin_from, coin_to):
+        rv = {}
+        ci_from = self.ci(int(coin_from))
+        ci_to = self.ci(int(coin_to))
+
+        name_from = ci_from.coin_name().lower()
+        name_to = ci_to.coin_name().lower()
+        url = 'https://api.coingecko.com/api/v3/simple/price?ids={},{}&vs_currencies=usd'.format(name_from, name_to)
+        headers = {'User-Agent': 'Mozilla/5.0'}
+        req = urllib.request.Request(url, headers=headers)
+        js = json.loads(urllib.request.urlopen(req).read())
+        rate = float(js[name_from]['usd']) / float(js[name_to]['usd'])
+        js['rate'] = ci_to.format_amount(rate, conv_int=True, r=1)
+        rv['coingecko'] = js
+
+        url = 'https://api.bittrex.com/api/v1.1/public/getticker?market={}-{}'.format(ci_from.ticker(), ci_to.ticker())
+        headers = {'User-Agent': 'Mozilla/5.0'}
+        req = urllib.request.Request(url, headers=headers)
+        js = json.loads(urllib.request.urlopen(req).read())
+        rv['bittrex'] = js
+
+        return rv
diff --git a/basicswap/explorers.py b/basicswap/explorers.py
index bff1ab0..0f090a4 100644
--- a/basicswap/explorers.py
+++ b/basicswap/explorers.py
@@ -1,11 +1,11 @@
 # -*- coding: utf-8 -*-
 
-# Copyright (c) 2019 tecnovert
+# Copyright (c) 2019-2021 tecnovert
 # Distributed under the MIT software license, see the accompanying
 # file LICENSE or http://www.opensource.org/licenses/mit-license.php.
 
-import urllib.request
 import json
+import urllib.request
 
 
 class Explorer():
diff --git a/basicswap/http_server.py b/basicswap/http_server.py
index 79833ef..c1c7e97 100644
--- a/basicswap/http_server.py
+++ b/basicswap/http_server.py
@@ -42,6 +42,8 @@ from .js_server import (
     js_network,
     js_revokeoffer,
     js_smsgaddresses,
+    js_rates,
+    js_rate,
     js_index,
 )
 from .ui import (
@@ -507,6 +509,12 @@ class HttpHandler(BaseHTTPRequestHandler):
 
         if 'amt_to' in parsed_data and 'amt_from' in parsed_data:
             parsed_data['rate'] = ci_from.make_int(parsed_data['amt_to'] / parsed_data['amt_from'], r=1)
+            page_data['rate'] = ci_to.format_amount(parsed_data['rate'])
+
+        page_data['amt_var'] = True if have_data_entry(form_data, 'amt_var') else False
+        parsed_data['amt_var'] = page_data['amt_var']
+        page_data['rate_var'] = True if have_data_entry(form_data, 'rate_var') else False
+        parsed_data['rate_var'] = page_data['rate_var']
 
         if b'step1' in form_data:
             if len(errors) == 0 and b'continue' in form_data:
@@ -616,6 +624,11 @@ class HttpHandler(BaseHTTPRequestHandler):
         if 'addr_to' in parsed_data:
             extra_options['addr_send_to'] = parsed_data['addr_to']
 
+        if parsed_data.get('amt_var', False):
+            extra_options['amount_negotiable'] = parsed_data['amt_var']
+        if parsed_data.get('rate_var', False):
+            extra_options['rate_negotiable'] = parsed_data['rate_var']
+
         offer_id = swap_client.postOffer(
             parsed_data['coin_from'],
             parsed_data['coin_to'],
@@ -1129,6 +1142,8 @@ class HttpHandler(BaseHTTPRequestHandler):
                             'network': js_network,
                             'revokeoffer': js_revokeoffer,
                             'smsgaddresses': js_smsgaddresses,
+                            'rate': js_rate,
+                            'rates': js_rates,
                             }.get(url_split[2], js_index)
                 return func(self, url_split, post_string, is_json)
             except Exception as ex:
diff --git a/basicswap/js_server.py b/basicswap/js_server.py
index b7c2cf3..07403db 100644
--- a/basicswap/js_server.py
+++ b/basicswap/js_server.py
@@ -19,6 +19,7 @@ from .chainparams import (
 )
 from .ui import (
     PAGE_LIMIT,
+    getCoinType,
     inputAmount,
     describeBid,
     setCoinFilter,
@@ -245,10 +246,6 @@ def js_revokeoffer(self, url_split, post_string, is_json):
     return bytes(json.dumps({'revoked_offer': offer_id.hex()}), 'UTF-8')
 
 
-def js_index(self, url_split, post_string, is_json):
-    return bytes(json.dumps(self.server.swap_client.getSummary()), 'UTF-8')
-
-
 def js_smsgaddresses(self, url_split, post_string, is_json):
     swap_client = self.server.swap_client
     if len(url_split) > 3:
@@ -276,3 +273,61 @@ def js_smsgaddresses(self, url_split, post_string, is_json):
             return bytes(json.dumps({'edited_address': address}), 'UTF-8')
 
     return bytes(json.dumps(swap_client.listAllSMSGAddresses()), 'UTF-8')
+
+
+def js_rates(self, url_split, post_string, is_json):
+    if post_string == '':
+        raise ValueError('No post data')
+    if is_json:
+        post_data = json.loads(post_string)
+        post_data['is_json'] = True
+    else:
+        post_data = urllib.parse.parse_qs(post_string)
+
+    sc = self.server.swap_client
+    coin_from = get_data_entry(post_data, 'coin_from')
+    coin_to = get_data_entry(post_data, 'coin_to')
+    return bytes(json.dumps(sc.lookupRates(coin_from, coin_to)), 'UTF-8')
+
+
+def js_rate(self, url_split, post_string, is_json):
+    if post_string == '':
+        raise ValueError('No post data')
+    if is_json:
+        post_data = json.loads(post_string)
+        post_data['is_json'] = True
+    else:
+        post_data = urllib.parse.parse_qs(post_string)
+
+    sc = self.server.swap_client
+    coin_from = getCoinType(get_data_entry(post_data, 'coin_from'))
+    ci_from = sc.ci(coin_from)
+    coin_to = getCoinType(get_data_entry(post_data, 'coin_to'))
+    ci_to = sc.ci(coin_to)
+
+    # Set amount to if rate is provided
+    rate = get_data_entry_or(post_data, 'rate', None)
+    if rate is not None:
+        amt_from_str = get_data_entry_or(post_data, 'amt_from', None)
+        amt_to_str = get_data_entry_or(post_data, 'amt_to', None)
+
+        if amt_from_str is not None:
+            rate = ci_to.make_int(rate, r=1)
+            amt_from = inputAmount(amt_from_str, ci_from)
+            amount_to = ci_to.format_amount(int((amt_from * rate) // ci_from.COIN()), r=1)
+            return bytes(json.dumps({'amount_to': amount_to}), 'UTF-8')
+        if amt_to_str is not None:
+            rate = ci_from.make_int(1.0 / float(rate), r=1)
+            amt_to = inputAmount(amt_to_str, ci_to)
+            amount_from = ci_from.format_amount(int((amt_to * rate) // ci_to.COIN()), r=1)
+            return bytes(json.dumps({'amount_from': amount_from}), 'UTF-8')
+
+    amt_from = inputAmount(get_data_entry(post_data, 'amt_from'), ci_from)
+    amt_to = inputAmount(get_data_entry(post_data, 'amt_to'), ci_to)
+
+    rate = ci_to.format_amount(ci_from.make_int(amt_to / amt_from, r=1))
+    return bytes(json.dumps({'rate': rate}), 'UTF-8')
+
+
+def js_index(self, url_split, post_string, is_json):
+    return bytes(json.dumps(self.server.swap_client.getSummary()), 'UTF-8')
diff --git a/basicswap/templates/offer.html b/basicswap/templates/offer.html
index 21a1e7a..764ea09 100644
--- a/basicswap/templates/offer.html
+++ b/basicswap/templates/offer.html
@@ -60,8 +60,15 @@
 <option value="-1" {% if data.nb_addr_from=="-1" %} selected{% endif %}>-- New Address --</option>
 </select>
 </td></tr>
-<tr><td>Minutes valid</td><td><input type="number" name="validmins" min="10" max="1440" value="{{ data.nb_validmins }}"></td></tr>
 
+{% if data.amount_negotiable == true %}
+<tr><td>Amount</td><td><input type="text" name="bid_amount" value="{{ data.amt_from }}"></td></tr>
+{% endif %}
+{% if data.rate_negotiable == true %}
+<tr><td>Rate</td><td><input type="text" name="bid_rate" value="{{ data.rate }}"></td></tr>
+{% endif %}
+
+<tr><td>Minutes valid</td><td><input type="number" name="validmins" min="10" max="1440" value="{{ data.nb_validmins }}"></td></tr>
 <tr><td><input type="submit" name="sendbid" value="Send Bid"><input type="submit" name="cancel" value="Cancel"></td></tr>
 </table>
 {% else %}
diff --git a/basicswap/templates/offer_confirm.html b/basicswap/templates/offer_confirm.html
index ba75b9a..26db9bf 100644
--- a/basicswap/templates/offer_confirm.html
+++ b/basicswap/templates/offer_confirm.html
@@ -59,10 +59,13 @@
 <option value="100"{% if data.fee_to_extra==100 %} selected{% endif %}>100%</option>
 </select></td></tr>
 {% endif %}
+</td><td>Rate</td><td><input type="text" id="rate" name="rate" value="{{ data.rate }}" readonly></td></tr>
+<tr><td>Amount Variable</td><td colspan=3><input type="checkbox" id="amt_var" name="amt_var_" value="av" {% if data.amt_var==true %} checked="true"{% endif %} disabled></td></tr>
+<tr><td>Rate Variable</td><td colspan=3><input type="checkbox" id="rate_var" name="rate_var_" value="rv" {% if data.rate_var==true %} checked="true"{% endif %} disabled></td></tr>
 
 <tr class="padded_row"><td>Offer valid (hrs)</td><td><input type="number" name="validhrs" min="1" max="48" value="{{ data.validhrs }}" readonly></td></tr>
 <tr><td>Contract locked (hrs)</td><td><input type="number" name="lockhrs" min="1" max="64" value="{{ data.lockhrs }}" readonly></td>{% if data.swap_style != 'xmr' %}<td colspan=2>Participate txn will be locked for half the time.</td>{% endif %}</tr>
-<tr><td>Auto Accept Bids</td><td colspan=3><input type="checkbox" name="autoaccept_" value="aa" {% if data.autoaccept==true %} checked="true"{% endif %} disabled></td></tr>
+<tr><td>Auto Accept Bids</td><td colspan=3><input type="checkbox" id="autoaccept" name="autoaccept_" value="aa" {% if data.autoaccept==true %} checked="true"{% endif %} disabled></td></tr>
 </table>
 
 <input name="submit_offer" type="submit" value="Confirm Offer">
@@ -77,6 +80,12 @@
 {% if data.autoaccept==true %}
 <input type="hidden" name="autoaccept" value="aa">
 {% endif %}
+{% if data.amt_var==true %}
+<input type="hidden" name="amt_var" value="av">
+{% endif %}
+{% if data.rate_var==true %}
+<input type="hidden" name="rate_var" value="rv">
+{% endif %}
 </form>
 
 </body></html>
diff --git a/basicswap/templates/offer_new_1.html b/basicswap/templates/offer_new_1.html
index d64cc3f..490d4b2 100644
--- a/basicswap/templates/offer_new_1.html
+++ b/basicswap/templates/offer_new_1.html
@@ -22,26 +22,112 @@
 </select></td></tr>
 
 <tr><td>Coin From</td><td>
-<select name="coin_from"><option value="-1">-- Select Coin --</option>
+<select id="coin_from" name="coin_from" onchange="set_rate('coin_from');"><option value="-1">-- Select Coin --</option>
 {% for c in coins %}
 <option{% if data.coin_from==c[0] %} selected{% endif %} value="{{ c[0] }}">{{ c[1] }}</option>
 {% endfor %}
 </select>
-</td><td>Amount From</td><td><input type="text" name="amt_from" value="{{ data.amt_from }}"></td><td>The amount you will send.</td></tr>
+</td><td>Amount From</td><td><input type="text" id="amt_from" name="amt_from" value="{{ data.amt_from }}" onchange="set_rate('amt_from');"></td><td>The amount you will send.</td></tr>
 
 <tr><td>Coin To</td><td>
-<select name="coin_to"><option value="-1">-- Select Coin --</option>
+<select id="coin_to" name="coin_to" onchange="set_rate('coin_to');"><option value="-1">-- Select Coin --</option>
 {% for c in coins %}
 <option{% if data.coin_to==c[0] %} selected{% endif %}  value="{{ c[0] }}">{{ c[1] }}</option>
 {% endfor %}
 </select>
-</td><td>Amount To</td><td><input type="text" name="amt_to" value="{{ data.amt_to }}"></td><td>The amount you will receive.</td></tr>
+</td><td>Amount To</td><td><input type="text" id="amt_to" name="amt_to" value="{{ data.amt_to }}" onchange="set_rate('amt_to');"></td><td>The amount you will receive.</td></tr>
+</td><td>Rate</td><td><input type="text" id="rate" name="rate" value="{{ data.rate }}" onchange="set_rate('rate');"></td><td>Lock Rate: <input type="checkbox" id="rate_lock" name="rate_lock" value="rl"></td></tr>
+
+<tr><td>Amount Variable</td><td><input type="checkbox" id="amt_var" name="amt_var" value="av" {% if data.amt_var==true %} checked="true"{% endif %}></td></tr>
+<tr><td>Rate Variable</td><td><input type="checkbox" id="rate_var" name="rate_var" value="rv" {% if data.rate_var==true %} checked="true"{% endif %}></td></tr>
 </table>
 
 <input name="continue" type="submit" value="Continue">
+<input name="check_rates" type="button" value="Lookup Rates" onclick='lookup_rates();'>
 <input type="hidden" name="formid" value="{{ form_id }}">
 <input type="hidden" name="step1" value="a">
 </form>
 
+<p id="rates_display"></p>
+
 <p><a href="/">home</a></p>
+<script>
+const xhr_rates = new XMLHttpRequest();
+xhr_rates.onload = () => {
+    if (xhr_rates.status == 200) {
+        const obj = JSON.parse(xhr_rates.response);
+
+        inner_html = '<pre><code>' + JSON.stringify(obj, null, '  ') + '</code></pre>';
+        document.getElementById('rates_display').innerHTML = inner_html;
+    }
+}
+
+const xhr_rate = new XMLHttpRequest();
+xhr_rate.onload = () => {
+    if (xhr_rate.status == 200) {
+        const obj = JSON.parse(xhr_rate.response);
+
+        if (obj.hasOwnProperty('rate')) {
+            document.getElementById('rate').value = obj['rate'];
+        } else
+        if (obj.hasOwnProperty('amount_to')) {
+            document.getElementById('amt_to').value = obj['amount_to'];
+        } else
+        if (obj.hasOwnProperty('amount_from')) {
+            document.getElementById('amt_from').value = obj['amount_from'];
+        }
+    }
+}
+
+function lookup_rates() {
+    const coin_from = document.getElementById('coin_from').value;
+    const coin_to = document.getElementById('coin_to').value;
+
+    if (coin_from == '-1' || coin_to == '-1') {
+        alert('Coins from and to must be set first.');
+        return;
+    }
+
+    xhr_rates.open('POST', '/json/rates');
+    xhr_rates.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
+    xhr_rates.send('coin_from='+coin_from+'&coin_to='+coin_to);
+}
+
+function set_rate(value_changed) {
+    const coin_from = document.getElementById('coin_from').value;
+    const coin_to = document.getElementById('coin_to').value;
+    const amt_from = document.getElementById('amt_from').value;
+    const amt_to = document.getElementById('amt_to').value;
+    const rate = document.getElementById('rate').value;
+    const lock_rate = document.getElementById('rate_lock').checked;
+
+    if (coin_from == '-1' || coin_to == '-1') {
+        return;
+    }
+
+    params = 'coin_from='+coin_from+'&coin_to='+coin_to;
+    if (value_changed == 'rate' || (lock_rate && value_changed == 'amt_from')) {
+        if (amt_from == '' || rate == '') {
+            return;
+        }
+        params += '&rate='+rate+'&amt_from='+amt_from;
+    } else
+    if (lock_rate && value_changed == 'amt_to') {
+        if (amt_to == '' || rate == '') {
+            return;
+        }
+        params += '&amt_to='+amt_to+'&rate='+rate;
+    } else {
+        if (amt_from == '' || amt_to == '') {
+            return;
+        }
+        params += '&amt_from='+amt_from+'&amt_to='+amt_to;
+    }
+
+    xhr_rate.open('POST', '/json/rate');
+    xhr_rate.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
+    xhr_rate.send(params);
+}
+
+</script>
 </body></html>
diff --git a/basicswap/templates/offer_new_2.html b/basicswap/templates/offer_new_2.html
index e821c2a..9da3e13 100644
--- a/basicswap/templates/offer_new_2.html
+++ b/basicswap/templates/offer_new_2.html
@@ -56,10 +56,15 @@
 <option value="100"{% if data.fee_to_extra==100 %} selected{% endif %}>100%</option>
 </select></td></tr>
 {% endif %}
+</td><td>Rate</td><td><input type="text" id="rate" name="rate" value="{{ data.rate }}" readonly></td></tr>
+<tr><td>Amount Variable</td><td colspan=3><input type="checkbox" id="amt_var" name="amt_var_" value="av" {% if data.amt_var==true %} checked="true"{% endif %} disabled></td></tr>
+<tr><td>Rate Variable</td><td colspan=3><input type="checkbox" id="rate_var" name="rate_var_" value="rv" {% if data.rate_var==true %} checked="true"{% endif %} disabled></td></tr>
+
 
 <tr class="padded_row"><td>Offer valid (hrs)</td><td><input type="number" name="validhrs" min="1" max="48" value="{{ data.validhrs }}"></td></tr>
 <tr><td>Contract locked (hrs)</td><td><input type="number" name="lockhrs" min="1" max="96" value="{{ data.lockhrs }}"></td>{% if data.swap_style != 'xmr' %}<td colspan=2>Participate txn will be locked for half the time.</td>{% endif %}</tr>
-<tr><td>Auto Accept Bids</td><td colspan=3><input type="checkbox" name="autoaccept" value="aa" {% if data.autoaccept==true %} checked="true"{% endif %}></td></tr>
+<tr><td>Auto Accept Bids</td><td colspan=3><input type="checkbox" id="autoaccept" name="autoaccept" value="aa" {% if data.autoaccept==true %} checked="true"{% endif %}></td></tr>
+
 </table>
 
 <input name="check_offer" type="submit" value="Continue">
@@ -69,6 +74,12 @@
 <input type="hidden" name="addr_from" value="{{ data.addr_from }}">
 <input type="hidden" name="coin_from" value="{{ data.coin_from }}">
 <input type="hidden" name="coin_to" value="{{ data.coin_to }}">
+{% if data.amt_var==true %}
+<input type="hidden" name="amt_var" value="true">
+{% endif %}
+{% if data.rate_var==true %}
+<input type="hidden" name="rate_var" value="true">
+{% endif %}
 </form>
 
 </body></html>
diff --git a/bin/basicswap_prepare.py b/bin/basicswap_prepare.py
index 327d4a7..17744f1 100755
--- a/bin/basicswap_prepare.py
+++ b/bin/basicswap_prepare.py
@@ -313,7 +313,7 @@ def prepareCore(coin, version_pair, settings, data_dir):
     extractCore(coin, version_pair, settings, bin_dir, release_path)
 
 
-def prepareDataDir(coin, settings, chain, particl_mnemonic, use_containers=False)):
+def prepareDataDir(coin, settings, chain, particl_mnemonic, use_containers=False):
     core_settings = settings['chainclients'][coin]
     bin_dir = core_settings['bindir']
     data_dir = core_settings['datadir']
diff --git a/doc/release-notes.md b/doc/release-notes.md
index e82197f..01380ca 100644
--- a/doc/release-notes.md
+++ b/doc/release-notes.md
@@ -2,21 +2,22 @@
 0.0.27
 ==============
 
-- Track failed and successful swaps by address
+- Track failed and successful swaps by address.
+- Added rate lookup helper when creating offer.
 
 
 0.0.26
 ==============
 
-- Added protocol version to order and bid messages
+- Added protocol version to order and bid messages.
 - Moved chain start heights to bid.
-- Avoid scantxoutset for decred style swaps
-- xmr: spend chain B lock tx will look for existing spends
+- Avoid scantxoutset for decred style swaps.
+- xmr: spend chain B lock tx will look for existing spends.
 - xmrswaps:
   - Setting state to 'Script tx redeemed' will trigger an attempt to redeem the scriptless lock tx.
   - Node will wait for the chain B lock tx to reach a spendable depth before attempting to spend.
 - ui: Sort settings page by coin name.
-- ui, xmr: List of candidate remote XMR daemon urls can be set through the http ui
+- ui, xmr: List of candidate remote XMR daemon urls can be set through the http ui.
 
 
 0.0.25
@@ -24,8 +25,8 @@
 
 - Fix extra 33 bytes in lock spend fee calculation.
 - XMR swaps use watchonly addresses to save the lock tx to the wallet
-  - Instead of scantxoutset
-- Add missing check of leader's lock refund tx signature result
+  - Instead of scantxoutset.
+- Add missing check of leader's lock refund tx signature result.
 - Blind part -> XMR swaps are possible:
   - The sha256 hash of the chain b view private key is used as the nonce for transactions requiring cooperation to sign.
   - Follower sends a public key in xmr_swap.dest_af.
@@ -45,14 +46,14 @@
 0.0.23
 ==============
 
-- Enables private offers
+- Enables private offers.
 
 
 0.0.22
 ==============
 
 - Improved wallets page
-  - Consistent wallet order
+  - Consistent wallet order.
   - Separated RPC calls into threads.
 
 
@@ -67,5 +68,5 @@
 0.0.6
 ==============
 
-- Experimental support for XMR swaps.
-  - Single direction only, scriptless -> XMR
+- Experimental support for XMR swaps
+  - Single direction only, scriptless -> XMR.
diff --git a/tests/basicswap/test_other.py b/tests/basicswap/test_other.py
index aa3f944..a9a89f1 100644
--- a/tests/basicswap/test_other.py
+++ b/tests/basicswap/test_other.py
@@ -29,10 +29,10 @@ from basicswap.basicswap_util import (
     SEQUENCE_LOCK_BLOCKS,
     SEQUENCE_LOCK_TIME)
 from basicswap.util import (
-    SerialiseNum,
-    DeserialiseNum,
     make_int,
+    SerialiseNum,
     format_amount,
+    DeserialiseNum,
     validate_amount)